content
stringlengths 71
484k
| url
stringlengths 13
5.97k
|
|---|---|
Our goal is to provide innovative, practical, cost-effective environmental services that meet the specific needs of our clients. We focus on technical excellence, effective communication, top-rate customer service, and timely, on-budget performance.
Company Overview
Habitat Management, managed by Mr. Wayne Erickson and Mr. Ken Carlson, specializes in environmental projects, land reclamation and permitting, and regulatory affairs. We use our broad experience base to evaluate projects, and propose and implement practical strategies. We help our clients achieve their business objectives, while ensuring regulatory compliance. We serve oil and gas, mining, alternative energy and private, public and tribal natural resource management clients.
Scientific Expertise
Habitat Management is committed to providing high value service and innovative solutions using objective science and current technologies and methods. Our staff of environmental scientists, biologists, ecologists, botanists, soil scientists, and regulatory experts delivers quality products to our clients.
Equipment and Technology
Habitat Management’s environmental services are streamlined through the use of top-of-the-line equipment and technology for most site-specific projects. Our staff is highly trained in a variety of programs that support environmental and engineering work, including SedCad, AutoCad and ArcView. We are experienced in using and developing geographic information systems (GIS), and have Trimble grade capabilities. | http://habitatmanagementinc.com/about/ |
A diverge group of interests from physicists and social scientists, communicators and journalists.
The theme of the Chapman Conference requires conveners from at least two areas that are critical to this conference: (1) Climate science and (2) Climate science history and communication.
The first category includes experts who are familiar with both the underlying methodologies and the outcomes of climate research; have expertise in broader implication of climate change (like environmental change); and have experience in exploration into the bleeding edge areas of climate science (like geoengineering) that may challenge accepted notions of climate science, and governance.
The second category could include scientists with experience and expertise in communication of technical information in a non-technical way and making complex issues accessible to policymakers and the public as well as professional historians and science journalists. Scientists can benefit from a historical perspective on how climate science was communicated in the past, which may help to develop more effective climate change communication strategies for the future. | https://chapman.agu.org/climatescience/who-should-attend/ |
See below for a Science Says-only offer for a visual science communication course from Picture As Portal (Valid through the end of the month) and an upcoming event on science & art! Read on to find out more, and please share widely with your networks.
Science Book Club
We're reading The Emperor of All Maladies by Siddhartha Mukherjee for this winter-spring book club. The next meeting is Wednesday April 7th at 6:00pm. To learn more and get on the email list, check out the link below.
April: Art and Science for Impact
Science Says is hosting Stephanie Fine Sasse, founder of The Plenary, on April 22nd at 5:30pm. Stephanie will be exploring the relationship between art and science, how they serve as complementary forms of inquiry, and ways scientists can leverage the arts/collaborate with artists to drive impact.
May: California Academy of Science
Science Says is hosting Drs. Peter Roopnarine, Elizabeth Babcock and Sarah Jacobs from the California Academy of Science on May 20th at 12pm to discuss how they brought their academic skills to the museum setting, as well as what they are doing now.
Coming Soon: Dr. Janet Iwasa
Dr. Janet Iwasa is an Assistant Professor in the Biochemistry Department of University of Utah. She specializes in creating accurate scientific illustrations and animations to support research and science communication efforts. Details coming soon.
Sharing SciComm Projects
Do you have a cool science communication project you'd like to share? Are you interested in trying blog writing? Email us at [email protected].
Women's History Month
In March, we celebrated women in science all month long. If you missed the posts on social media, you can read all about the women we highlighted (and a few more!) below.
A Statement of Support
In light of the recent attacks on the Asian-American community and increase in anti-Asian xenophobia throughout the pandemic, we felt it was necessary to reassert our commitment to anti-racism and diversity, equity and inclusion efforts.
North Bay Science Discovery Day
Discovery Days are free, multi-location grand finales of the Bay Area Science Festivals, and we participated (virtually) this year with a team of scientists leading career panels and general Q&A about science.
Is the "Love" Hormone Making Us Socially Anxious?
We have all experienced nervousness before a social engagement at some point. As social beings, it is normal human behavior to care about what others think of you. But what happens when you care too much? In her latest article, Heather Mayer explores social anxiety research being conducted at UC Davis in the Trainor Lab.
Resources, Opportunities, and Virtual Events
Let us know if you hear about any resources or opportunities that our group may be interested in! [email protected]
Volunteer for a "Meet a Scientist" Panel!
Practice your scicomm, build your outreach and tell your science story (or stories about your science)! Science Says meets virtually with classrooms and public science events like North Bay Science Discovery Day to talk about our journeys and answer audience questions.
Picture as Portal Visual Science Communication Course
In this course, you’ll learn a sequence of 5 strategies for communicating science in a picture—based on the easy-to-remember acronym S.P.A.R.K. Each letter represents one strategy. You’ll learn exactly how a picture evolves from beginning to end. As you progress through the course, you'll see step-by-step demos of each strategy applied to a case study image.
S.P.A.R.K. is perfect for you if—right now—you’re working on a presentation, a paper, or a project, and find yourself struggling to communicate clearly. Follow S.P.A.R.K.’s step-by-step process, and you will have a picture by the end of the course. And we think you’ll be surprised by what you’re able to accomplish!
You’ll learn core concepts of visual communication that’ll be useful whether you’re an expert or a student, a novice or a pro. This is not a course on how to draw. What you’ll learn can be applied to many different ways of presenting information—such as diagrams, charts, or data visualizations. Your pictures can be drawn by hand, or you can use software you already know.
Science Communication Fellowship Program
The Science Communication Network’s unique Science Communication Fellowship Program is Now Accepting Applications for a 9-month fellowship beginning Sept. 2021.
For early-career green chemistry/engineering and environmental health scientists working at the intersection of environment, health and safer materials. This program is for researchers who want to maximize the impact of their work to benefit public health and the environment, and share their passion for science. The program focuses on the skills necessary for confident and effective engagement with the range of non-scientists - including journalists - researchers will encounter in their careers as they share rapidly evolving environmental health and green chemistry research. Learn more at https://sciencecommunicationnetwork.org/fellows Questions can be sent to [email protected]
ComSciCon Conference
The 9th annual ComSciCon Flagship Workshop will take place virtually August 4-7, 2021! ComSciCon provides graduate student attendees with a one-of-a-kind opportunity to meet early career leaders in Science Communication, learn from and interact with a remarkable group of invited experts, and produce an original work communicating complex technical concepts from science and engineering to a new audience.
At ComSciCon's Flagship Workshop, participants build communication skills that scientists and other technical professionals need to express ideas to their peers, experts in other fields, and the general public. Applications for attendance are due Thursday April 15th.
SciPEP Conference
On July 27-28, 2021, SciPEP will convene a FREE virtual conference exploring the unique characteristics of the relationship between the public and basic research, drawing from the experience and expertise of our colleagues in the science and science communication communities. Communicating the Future: Engaging the Public in Basic Science will explore why the public and basic science should be connected and what current communication and engagement efforts are taking place, including the challenges and opportunities in this work. Ultimately, we intend to identify how scientists and professionals can work to engage the public with basic research as effectively as possible.
The conference program will be organized around the exploration of the why, what and how of the relationship between the public and basic science. | https://davissciencesays.ucdavis.edu/news/april-newsletter-0 |
How many climate scientists are climate skeptics?
Posted on 22 June 2010 by John Cook
There have been various surveys or petitions claiming that thousands of scientists are skeptical that humans are causing global warming. The thing is, when you peruse these lists, you find very few scientists who actually have expertise in climate science. So what do the experts think? A 2009 survey found that over 97% of actively publishing climate scientists are convinced humans are significantly changing global temperatures (Doran 2009). Now a new study has digged into this topic a little deeper and broader. As well as covering a larger number of climate scientists, they also researched how many papers each scientist published and how often their work was cited (Anderegg 2010). How many published climate scientists think most of recent global warming was due to human activity? Between 97 to 98%.
The results are strikingly consistent with Doran's earlier work. The overwhelming majority of climate experts think humans are causing climate change. Next, they dig a little deeper. They examine the number of publications by each scientist as a measure of expertise in climate science. What they find is the average number of publications by unconvinced scientists (eg - skeptics) is around half the number by scientists convinced by the evidence. Not only is there a vast difference in the number of convinced versus unconvinced scientists, there is also a considerable gap in expertise between the two groups.
Figure 1: Distribution of the number of researchers convinced by the evidence of anthropogenic climate change and unconvinced by the evidence with a given number of total climate publications.
An alternative measure of the quality and credibility of a scientist's contribution is the number of times their work is cited by other scientists. Again, there is a considerable gap between the number of citations of papers by convinced scientists and unconvinced scientists.
Figure 2: Distribution of the number of researchers convinced and unconvinced of human caused climate change with a given number times cited for each researcher’s average of the first through fourth most-cited papers.
Skeptics claim there is no scientific consensus, that there are many scientists who don't think humans are causing global warming. However, when it comes to climate experts, we have a numbers gap, an expertise gap and a credibility gap between the scientists convinced of human caused global warming and climate skeptics. | https://skepticalscience.com/news.php?p=1&t=130&&n=237 |
Four of Australia’s leading visual creators from our latest creativity project share their top shots and the thinking behind them.
Inspired by landscapes and a love of travel, Rach Stewart likes to explore the unknown, and find the all-important elements that connect humans with nature.
What happens when you give four different photographers a wedding dress, and ask them to produce a single image, with no brief.
A discussion of women’s surf imagery in 2017.
What happens when you take on a photo shoot, and all your inner thoughts, questions and doubts become impossible to ignore? Inner Critic—the latest experiment from THE LAB—aims to find out.
One of the participants from Inner Critic—the latest experiment from THE LAB—reflects on her experience and the impact the challenge has had on her professionally.
It’s a simple truth. If we’re always looking for inspiration in the same places, we’re likely to come up with similar results.
Underwater photographer and Tales by Light explorer Eric Cheng is spell-bound by the majesty of the sea. Read his story here.
Over two decades, the award-winning Canon Master Stephen Dupont has been a champion for the people of fragile and marginalised cultures through his hauntingly beautiful and intimate photographs of humanity. | https://www.canon.co.nz/explore/stories |
Whether you see him in the hallways giving out high fives or hear him cracking jokes in his classes with his quirky sense of humor, just about everyone at WCHS knows who senior Avi Grant is. However, what some may not be aware of is Grant’s love for photography, and how it has shaped who he is today.
Grant has been taking photos of different subjects for many years, having first started when he was roughly 10 years old. Since then, his interest in the world of photography has grown exponentially, and he now takes every opportunity he can to find just the right angle for his next shot—whether it be of WCHS, the starry night sky or even a political march.
“I have always enjoyed photographing subjects that capture my eye,” Grant said. “I really appreciate the fact that I can freeze moments in time through photography. It sparks an interest in me and it’s a lot of fun when the finished work turns out well.”
The limit to Grant’s variety of subjects knows no bounds, and for this reason he has even adopted his own unique style. While he has a wide array of subjects to choose from when taking photos, there are several that capture Grant’s interest more than most.
“Nature can be fun to photograph, and I like architectural or historical subjects,” Grant said. “I try to show what different regions look like, from the environment of an area, to the buildings and historical aspects of different places I visit with my family. I also use my photography to try to show new perspectives on the world.”
Of these new perspectives, Grant is quite outspoken on the topic of environmental conservation and sustainability. Along with the photos he shoots, Grant uses his social media accounts, primarily his Instagram (@avi_g2000photography), to discuss these issues and many more.
“This past Earth Day, I posted photos I had taken in national parks during a trip the previous summer,” Grant said. “I wrote a long caption describing why the environment needs to be protected for generations to come.”
Grant finds some of his influence and inspiration through the social media accounts that he follows. However, in order to continue discovering his own creativity and artistic expression, he simply keeps practicing through trial and error.
“I follow some cool photographers on Instagram,” Grant said. “But I mostly experiment on my own and photograph from different angles and perspectives to try to capture something new. It is a great way for me to express my abilities and be creative.”
While much of Grant’s work focuses on subjects on Earth, he also finds time in his schedule to grab his tripod and take photos of the stars. This subgenre, known as astrophotography, is just one of the many different aspects of Grant’s art.
“Astrophotography is the process of taking photos of the night sky by using a long exposure time to collect more light than what is just visible with your naked eye,” Grant said. “It’s fun, and although time consuming, it can be really satisfying when the photo turns out just right.”
In addition to his affinity for nature and astronomy, Grant has displayed a keen aptitude for getting shots of political protests and marches, effortlessly showcasing the raw emotion of the people in his photographs.
“I like to put across a message supporting my views,” Grant said. “I documented the student led ‘March for Our Lives’ event and another march that occurred this year.”
With all of the effort and dedication that Grant has put into his craft, it should come as no surprise that he has managed to leave an impact on those around him. Perhaps the greatest proponent of Grant’s commitment to the artform is none other than his photography teacher.
“He has a very nice eye for composition; I see it improving as time goes on,” Photography teacher Amy Gilbert said. “I see him improving on putting the meaning he intends into his work, which is a really hard skill to master.”
Despite Grant’s overwhelming excellence in the field of photography, he views it more as a hobby rather than a potential full-time career. While he will most likely pursue and major in a subject other than photography in college, he has no intention of dropping this hobby any time soon.
“[Photography] will probably be more of a hobby,” Grant said. “Unless I find a major I am interested in that can involve photography and lead to a profitable career. Hopefully, I will continue to take photographs forever—someday I want to get a better camera.”
Ultimately, the greatest inspiration for Grant’s photography is how it allows him to connect to the WCHS community. Through his art, Grant communicates and conveys a message to the many students who attend this school, and that is more than enough of a reward for him. | https://www.thechurchillobserver.com/arts/2018/11/20/student-art-spotlight-avi-grant/?print=true |
Do you want to push your photography skills further? Would you like to find out how to hone your photographic skills? Photographs that you find interesting are likely to be interesting to other people, as well. All of this tips in this article will help you improve your photography skills.
Use the features of the camera to improve your shots. You can use a shallow depth to help draw attention to the actual subject of the shot and blur the backgrounds.
Make sure that your arms remain next to your body when you hold a camera, and make sure that the sides and the bottom of the camera are supported. This will help to steady your hands and prevent blurry shots. Holding the camera from the bottom and underneath the lens also helps prevent dropping your camera accidentally.
Take a lot of experimental photographs when you are working with a new subject or background. Every photographic opportunity is different, and taking several practice shots can help you figure out the best way to approach the picture. You have very little control over your surroundings, so realize that changes in weather or scenery can provide different types of lighting. Make sure to snap plenty of practice shots to make sure you’re getting the right shot.
Whenever you are going somewhere new, get some ideas for taking pictures. If you’re looking for ideas, a great place to start is by checking out postcards. You will want to create your own images and perspectives of these important places.
You may think the flash on your camera is only for indoors, but if you use it outdoors, where strong light produces deep shadows, the flash will reduce the shadows in your picture. Not using a flash will leave unnatural shadows on your subject’s face.
Make sure to read the camera’s manual. Manuals can be intimidatingly long. Often, people put them in a file drawer or throw them in the garbage. You should take time to read the manual or else you might break the camera or get frustrated with settings. The information contained within is extremely valuable and will simplify the process of taking great pictures.
Don’t restrict yourself to taking pictures of your subject from only one angle. Be creative and reposition your shots so that you can experiment with different angles. Unique angles can add an artistic element to your pictures.
Try to get close to the subject of your photograph when you take your shot. Your subject should cover what you see through your camera. This is an effective technique when shooting flowers or still-life subjects. Utilize the zoom feature on your camera if you cannot physically get close to the object.
When photographing children, be prepared for a dynamic, energetic shoot you can not control. It’s next to impossible to get children to sit still for a photograph as they tend to have a lot of energy. The best way to combat this is to take advantage of it. Have a little fun and get action shots of them instead.
After reading this article, hopefully you’re full of ideas and ready to start experimenting with new techniques. The tips that you have been reading should work well for you. If they don’t, try something different until you are happy with its benefits. | http://digitalartsinstitute.com/achieve-picture-perfect-results-with-these-photography-tips-3/ |
1. Frame Your Subject
Framing an image correctly can draw a lot of attention. This can be done by using one element of an image and framing it with another element of the image. When framing is done correctly, it can give an image depth and draws attention to the desired point of interest on an image.
2. Wide Angles
Photos taken on a camera using a wide-angle lens can create memorable shorts when doing a portrait photoshoot.
Wide focal lengths can create a distortion, which can improve an image. However, it can enlarge parts of the face or body that are on the edge of a frame in contrast with the centre. Therefore, this would be ideal for a playful type of shoot. It can also give a wide open and dramatic impact when your subject is in a great setting.
3. Play With Backgrounds
The main point of interest is the person in the portrait. However, when the person is placed in diverse backgrounds this can drastically change the mood in the shot, which can be good depending on what type of look you are going for. Whereas other times you may prefer to keep your background minimalistic. It is essential to experiment to know which background is most suitable for your image.
4. Change Format Framing
Photographers tend to stick to shooting in landscape or portrait modes. However, although vertical framing is referred to as ‘portrait’ mode, it doesn’t necessarily mean that you need to use this mode when shooting portraits. Mixing up your framing will add variety to the type of shots you take. This can bring creativity and a sense of fun to your photography shots. | https://www.69dropsstudio.co.uk/blog/4-tips-for-beautiful-photos/ |
Jesus Chamizo (Madrid 1961-) is an established Spanish photographer. He has been developing his work in different photographic areas such as art, architecture, interiors and landscapes combining them in concept, technique and creativity.
Award winner of many international and national prizes, including the New York Festival, Chamizo’s photographs are characterized by an interest in the tracks human beings leave behind in this world, architecture figuring prominently here. Chamizo builds images based on the emotions that space produces through lines, angles, light, perspectives and shapes. These elements are mostly visible in details of the buildings and they become protagonists of the compositions, opening our minds to new spaces. | http://www.lartban.com/artistas/jesus-chamizo/ |
Get Inspired by Enrique Martínez Celaya
Enrique Martínez Celaya (American, born Cuba, 1964) Bird, (detail), 1996, oil and fabric on canvas, 72 × 60 1/8 inches. Museum purchase with funds provided by the Contemporary Art Council, 6-1997.
Observe and document the natural world around you—including the plants, birds, insects and other natural elements. This might be seen in your yard or garden—or on a walk or hike. Take time to focus on the details; then photograph, sketch or paint what you see. Consider meaning and interpretations of your surroundings and your creation.
Supplies:
- Camera or camera phone
- Sketchpad, pencil and/or paper
Follow instructions below.
Step 1
Go outside! Take a walk in your yard or in your neighborhood, or go to a park or take a hike (if available to you in your location).
Step 2
Photograph or sketch plants and wildlife that you see along the way. Carefully observe your subjects from different perspectives and document them two to three times. Experiment with interesting angles and lighting.
Tip: Think about your focus (what’s sharp and directs the viewer) and composition (how images are placed within the overall frame).
Step 3
When you return home, select your favorite image(s). If you are using a camera or camera phone take time to edit, such as cropping out areas that take away from the main image. If you are sketching, redraw, paint or add color to your favorite sketch.
Step 4
Once your work is complete, take time to examine and uncover different meanings and interpretations.
Then, submit your artwork! | https://www.psmuseum.org/at-home/activity/activity-9 |
Learning more about photography is the best way to improve yourself. You can avoid big and silly photography mistakes so that you can capture everything you want.
When shooting pictures on an overcast day, avoid capturing the sky in the image. Your photo will look washed out if you have too much gray sky in it. If you cannot avoid capturing an overcast sky in your shot, opt for black and white rather than color photos. A bright, blue sky can create a lovely backdrop as long as you are careful not to overexpose the shot.
Play around with different color schemes, camera angles and photography features. You do not need an original object to take a high-quality picture. Ideally, a photographer is able to use his or her technical skills and artistic eye to add visual interest to even the most basic subject. Experiment as much as you can, and find your own style.
Consider documenting your souvenirs with photography during your travels. You could photograph the store you bought the item from, or you can place it somewhere with a unique background. You will always remember where the souvenirs you bought came from and you will have great stories to tell when showing them.
When you take photographs, write a couple of notes about them. When you are looking through the many photos you have taken, it can be hard to recall the locations in which you took them, or your feelings as you were doing it. Use a notepad to jot down a few notes about the pictures you take.
Try to get as close as you can to your photo subject. Subjects lacking in color or details are one of the worst things you can see in a photograph. Do everything you can to make sure your subject stands out and is seen clearly.
Pre-focus your camera and move the lens slightly in one direction so that the subject you are shooting is slightly off center. Viewing one photo after another where the subject is perfectly centered in the shot can become boring in a hurry. Taking an off-centered shot will make your subject more interesting to view.
Confine yourself within certain limits, to breed creativity. For example, pick a day to shoot only one kind of conceptual image, such as “sweet.” One way to improve technique in photography is to photograph the same object or scene over and over again. This can help you to be more creative by forcing you to step outside of your comfort zone.
Look around for good subjects for your photos, any time you are on the road. Have a look at the closest postcard rack for inspiration of where to begin. Usually the photos on these cards clue you in on popular and photo worthy local attractions and areas of interest, any of which usually make excellent subjects for your own. So, make an effort to visit these areas and attractions.
As you have learned from this article, taking stunning photographs is not out of your reach. All it requires is research, practice and implementing the tips given in this article. The work always pays off when you see the quality of your new photos. | https://hembryggning.org/affiliatesite/use-this-great-tips-about-photography-to-help-you-better-understand/ |
September 3 - At a Crossroad: Evolving as an Artist - 9/3 - 1:00 - 4:00p.m.
Do you think you have you taken your artwork as far as it can go?
Are you at a crossroads, tired of making the same sort of quilts, but unsure of the next step?
Do you have the urge to try different techniques, to add new elements or ways of working to your fabric art?
Has your work gotten stale, or is boring to you, so that you want to explore a different sort of creative expression?
If you answered 'YES' to any of these questions, you may be an artist in a rut, or you may have hit a brick wall.
This class is for the artist who has the urge to try something new in one's art, perhaps work with different materials add different sorts of elements, and take that art to a new level.
Is THIS your time? You are 'worth it'! Invest in yourself and try something new—and gain confidence in your ability to move from being stuck to transforming your work into something amazing!
This class is for the artist who has the courage to take her or his art to a new level.
If you know your visual voice and are comfortable with your style of artistic expression, but are tired of making the same quilts over and over, this class is for you. You will come away with an infusion of confidence, so that when you encounter problems, you will be inspired to work through to the solutions.
At Create on Maui, you will play with many new materials & techniques, experiment with new colors, and discover new results. Your creativity will get a boost of energy. Some techniques will really speak to you and you will develop expertise with them, adding some of them to your artwork. Perhaps you are ready to branch out and create an entirely new sort of art uniquely your own.
Please bring (or submit via .jpg) photographs of your work to facilitate Kathleen in helping you in your journey. | http://www.createonmaui.com/home/elective-classes/Evolving-as-an-Artist |
Tim Brown — 18 July 2022
Despite what people might think, creativity in the workplace is not just the purview of the marketing or R&D departments. All departments – and indeed all industries – can benefit greatly from nurturing creative thinking.
This is because creativity in the workplace:
So are you ready to unleash the benefits of creativity in your business? Here are 4 ways to nurture creativity in the workplace.
1. Encourage autonomy and individuality
According to research by Professor Teresa M. Amabile of the Harvard Business School, creativity is highly driven by intrinsic motivation, or a person’s internal desire to do something. She calls this the Intrinsic Motivation Principle of Creativity, where “people will be most creative when they feel motivated primarily by the interest, satisfaction, and challenge of the work itself – and not by external pressures”.
One way to positively influence employees’ intrinsic motivation is by granting them autonomy and allowing them to express their individuality in how they do their jobs.
This doesn’t mean a total free-for-all. As Professor Amabile puts it, “Creativity thrives when managers let people decide how to climb a mountain; they needn’t, however, let employees choose which one.” In other words, creative output is enhanced when people are given clearly specified strategic goals, but are allowed the freedom to work out how to achieve those goals themselves. Fostering autonomy can also include giving teams the flexibility to work remotely or in a hybrid environment, which demonstrates that they are trusted to complete the work they are given.
2. Create space for creativity – and failure
When a business fails to acknowledge employees’ creative efforts, or constantly greets new ideas with criticism and skepticism, these attitudes can kill creativity in the workplace and discourage employees from sticking their neck out by offering new ideas.
Employees need to feel like the workplace is a safe space to suggest new ideas and experiment with different ways of doing things. Companies can provide a space for this by allowing employees to express their ideas without judgement and praising creative efforts – even those that may be unsuccessful. While not every innovation leads to desired results, they are always teachable lessons. So, reframe failures as learning opportunities, and ask yourself, “What can we take from this experience to help us succeed in the future?”.
3. Hire diverse talent
If creativity means thinking outside the box, the last thing you want when trying to nurture a more creative environment is for your teams to become echo chambers – which can easily happen if your business tends to hire people with similar backgrounds.
Instead, to encourage creativity in the workplace, create teams with a diversity of perspectives and backgrounds. This requires cultural, educational and professional diversity to bring different life experiences, expertise and thinking styles to the table for ideas to breed in exciting and useful ways.
When putting together such teams, it’s also worth thinking about those team members’ personalities. Creative teams do not only need to be diverse but also mutually supportive – members must be willing and enthusiastic about working towards the same goal, be willing to help their fellow teammates through setbacks, and must recognise and respect the unique knowledge and perspectives other members bring to the table. Building a creative team with just the right chemistry may not be easy, but the results have proven powerful.
4. Provide the necessary resources
It’s no good simply telling your employees to go off and be creative – they need the resources to do so effectively.
Resources may include:
Providing employees with the necessary resources sends a clear signal that the entire organisation encourages creativity and makes an effort to see it thrive.
Consciously nurture creativity
Nurturing creativity in the workplace has many advantages – more innovation and increased productivity, resulting in a healthier bottom line; more engaged and passionate employees; and greater flexibility allowing businesses to pivot quickly when needed. But to gain these advantages, companies need to make a conscious effort to create a culture that encourages creativity – not just in “creative” departments like marketing, but across the entire business.
To find out more about the tool that’s giving teams back their time to focus on more meaningful, strategic and creative work, get a demo of the Outfit platform in action. | https://outfit.io/blog/nurture-creativity-in-the-workplace |
To successfully capture a memorable landscape photo, you need to study various perspectives and vantage points from which you can shoot a particular outdoor scene.
Even gorgeous blue skies over snowcapped indigo mountains reflected in a still lake can be boring. We’ve seen that shot many times before. So the challenge with landscape photography is trying different perspectives on scenes we’ve all seen before.
One way to do this is to mentally divide the landscape into three parts – a foreground (F), a middle ground (M), and a background (B) – to tell the story of the landscape.
To illustrate the F-M-B concept, look at the photograph above. It was taken at a botanical garden with a lot of green space and trees.
By switching perspectives and angles, I was able to compose an interesting shot from a pretty boring scene by putting some intertwining flowers in the foreground, showing elements of the vast green space in the middle ground, and leaving the trees to serve as the background that encloses the scene.
Working with foregrounds, middle grounds, and backgrounds also adds depth to your photographs, giving viewers an idea of distance.
Here are a few more landscape shots to illustrate this concept.
So next time you’re shooting a landscape scene, try a slightly different perspective on your subject. Instead of focusing on rock formations themselves, why not focus on some elements such as trees and flowers in the foreground while keeping the main attraction slightly out of focus in the background?
Keep the F-M-B concept in mind when trying different perspectives. | https://www.lolaakinmade.com/phototips/photo-tip-create-depth-landscape-photos/ |
It’s easy to get stuck in a rut taking the identical sort of photographs and processing them in the identical way time and again. Figuring out how one can learn your histogram could be the difference between pondering you’ve an incredible photograph and actually having a great picture.
I have hundreds of photos from a ten-day trip to Eastern Europe, but at present I battle to inform buddies what metropolis I used to be standing in once I took a selected picture. The last one is very important and we should actually take our camera and get out of our home to photograph something.
One factor I exploit to spice up my creativity is to have a look at issues from different angles and views. However, study the foundations” and observe composition in other photographs that can assist you feel” what works finest. Find a location where the foreground and background shall be up to now out of your portrait-sitter that it is simple to make them stand out, even at f/5.6. | http://www.unicityfestival.com/superior-photography-skills.html |
Photography is a difficult art form to master. You need some degree of talent to succeed as a photographer, but the most important part of successful photography is putting in the effort to learn photographic techniques. However, if you are not a born photographer, you can certainly learn enough good technique to take great pictures.
Try not to capture a gray sky in your pictures. Including too much of a gray sky will make your pictures appear muted and washed-out. If you cannot exclude the overcast sky from your shots, you may want to consider taking black and white photos. A clear blue sky is always lovely in a photo, but adjust your settings to account for bright light.
Test varying shutter speeds to learn which speed works best for certain scenarios. Photography gives you the power to turn a series of single moments into a larger, more broad time frame. To freeze moving objects, try out a fast shutter speed. A slower shutter speed will help to capture calm, natural scenes.
Contrary to popular belief, gorgeous, sunny days are a photographer’s worst nightmare. You can’t take proper photographs if you or your subject is standing directly in the sun’s path. One or both of you will be uncomfortable, and the sun’s glare can make your subject difficult to see in the finished photograph. The sun will cast awkward shadows along with glaring, and cause uneven highlights that will make your subjects squint when they look into the camera. If you can, pick times early in the morning or later in the evening when taking pictures outside.
Overcast Sky
It’s best to use a blurred background when taking portrait shots. If the background is too crisp or clear, viewers may get distracted by it or be unsure of which part of your photograph to pay the most attention to. This loss of focus is achievable by increasing the distance between the person and the background.
Try not to capture an overcast sky when taking pictures. Capturing an excess of gray sky in your image can cause your pictures to look washed-out and muted. Although, if you are taking photos with black and white, you can shoot your photos with an overcast sky. If the day is not overcast, you can show as much of the sky as you want to, but make sure you are attentive to the lighting.
There’s so many different features to play with on your camera. Make sure you adjust your colors and angles while experimenting. Your subject does not have to be original in order for your photo to be unique. A good photographer should be able to make a picture of an unoriginal object look interesting, thanks to their skills and artistic talent. Practice and experiment until you find your own personal style!
A lot of people consider gorgeous days of abundant sunshine to be ideal for snapping good photos, but direct sunlight is actually a good way to mess up a good picture. Direct sun will cast shadows and cause glares but it will cause highlights that are uneven and your subjects may squint. Early morning or twilight are much better choices for photo shoots.
Having people in your pictures can add authenticity, perspective and interest. Of course, it is recommended to request permission first before snapping pictures. Do not try taking pictures of people who stand out. These pictures are going to remind you of a particular atmosphere when you look at them later. Find casual clothing and candid expression.
An important factor in photography composition, is framing. Zoom in on your subject or the most important part of the photo and cut out extraneous objects from the background. You can take away all of the clutter and unwanted objects in your pictures.
When you are photographing a particular subject, move around it. Try interesting angles such as shooting from above, underneath, moving from side to side of the subject, or holding the camera at waist level.
Many photographers pay attention to the background of a landscape shot and neglect the foreground, but the foreground is what the viewer will see. Make sure your foreground has a nice appearance and will show depth.
Figure out the best blend of aperture, ISO and shutter speed. These settings can determine what your picture will look like. Unless you are shooting for an artsy, atmospheric result, try to avoid under- or over-exposed photos. If you try out the different features and how they work together you can find what works best for you!
Shutter Speed
Finding another photographer to mentor you or joining a club can improve your photography skills. There is much to be learned from other people in this field, but make sure to maintain your own personal style. Looking at shot comparisons can show the different points of view found in photography.
Experiment with you camera’s shutter speed settings. When you know how the shutter speed affects your photographs, you can manipulate them to add interest to your pictures. A camera comes with a variety of settings. P,M,A and S are some of those options. Using the “P” setting will put your camera into program mode. This setting is automatic, which means you don’t have to worry about setting the shutter or aperture speed yourself. For general use, the “P” setting is the right one to choose.
If you are warming up for a wedding shoot, take pictures of simple, still subjects, such as a flower in the bouquet or the rings. Sometimes you will get some fantastic shots that are unexpected.
Take photographs of souvenirs and mementos gathered during your travels. For example, photograph the shop where you had originally purchased the memento, or frame the object against a memorable background. This creative project helps to create a more memorable connection with the objects and sights from your travels.
As you journy to new and different places, look for tips on what interesting things there are to photograph. A great place to help you generate ideas is to browse through local postcards that are for sale in small shops or others areas you visit. The postcards will show images of places and subjects that people would like to see and would be a welcome addition to your portfolio.
Make your subject feel comfortable, especially if you don’t know them. Many people feel threatened when a stranger starts photographing them. Help your model to relax by keeping a friendly atmosphere, and the mood upbeat. Also, seek their permission before you start taking their picture. Help people see photography as an art form, not as a way to invade their privacy.
It is important that you take the time to read your camera manual, and become familiar with your camera before you begin using it. Camera manuals have a certain bulky heft that discourages reading. They usually get shoved in the back of a drawer or just thrown away. Instead of throwing them out, use time to read its contents. You will find a lot of information that can improve your picture taking and stop silly mistakes from happening.
You might want to join a club or group that specializes in photography, or perhaps, find another person who has the same interests as you. Other people who share your interests can provide you with great information, but try not to let them influence the way you take your pictures. Compare your photos with your photo buddy to see what different approaches each of you had towards the same subjects.
With most photos, you will have to make the choice of how to properly expose highlights and shadows in the photograph. If you so choose, you can take two different pictures with different effects, and blend them together using programs such as Photoshop.
Add interest to a photograph by adjusting the focus at different points. A lower f-stop means that the main subject will be shaply focused in contrast to a blurry background. This is a good technique to use when the subject is up close, such as in portraits. If you use a bigger depth of field, more elements will enter into the point of focus of the picture. You’d use this technique when shooting landscapes.
You can be the editor of your own photos! There are quite a few different pieces of software that allow you to edit photographs. Find a software that you can edit your photos, however you want. Opt for the software program that appears to be the most user-friendly.
As you have just read in the above article, you can become a master of photography and have the skills necessary for a good career, something which isn’t available in many other occupations. There is more to photography than simply pointing and clicking a cheap camera. It is about forever immortalizing the beauty that surrounds you by capturing it in a photograph.
You should think about your approach before you start taking pictures. Sit down, and brainstorm some notes and ideas which will make your shot better. As with any form of art, it’s all in the details and execution of a concept or idea. Approaching photography in this way can create motivation and inspiration that will enhance the final product. | http://ryanphotography.org/tag/shutter-speed/ |
If you’re stuck at home, bored and want to practice composition, give selfies a go:
Selfies rule everything around me
Never stop studying your selfie
Analyze your selfies
Composition ideas
Some quick ideas. First idea: look to the side of the frame:
Head on bottom of the frame and look up
Tips and ideas
Chin up
- Shoot a lot. Experiment with both black and white *and* color
- Shoot from different angles and perspectives: low angle, high angle. Move your head while shooting.
- Try both horizontal and vertical orientations with your camera.
Don’t be shy.
You’re just shooting your self. Why be shy?
While practicing your composition, sketch your images on iPad, iPhone or whatever tool
Color vs black and white
Certainly there are different vibes with color and monochrome. As a general rule:
Monochrome feels more “artsy”, whereas color is more “true to life”.
You choose. | https://erickimphotography.com/blog/2020/09/30/how-to-practice-shooting-selfies-of-yourself-at-home/ |
Another 355,000 UK centre-points released
Over 455,000 not-yet-digitised aerial images of the UK can now be searched and ordered from our website. Each image is identified by a point on our map browser. These points show the locations of aerial survey photographs of places across the UK. Drawn from our Simmons Aerofilms, Airbus and UK Perspectives collections, the photographs date from the 1960's to the 2000's.
To search for photographs, Browse by Map and zoom to your area of interest. Find and click on the points to see the date and reference of each image. Click 'Buy' to order a copy at high resolution.
If you are not sure an image will completely cover your area of interest, add Image Verification to your order. | http://ncap.org.uk/news/another-355000-uk-centre-points-released |
Cee’s Fun Foto Challenge this week is all about Squares and Angles. This is one of my favorite aspects of photography. I love to experiment with different angles and learn how to compose the photo!
This photo from Dubrovnik, Croatia has lots of squares and angles! I was on top of the 2 mile wall that surrounds the City!
This unique structure at the Convention Center in Vancouver has very interesting angles.
I’m finding the more I participate in these challenges, the more I learn about photography. As I peruse my photos…I’ll find some that initially I glanced at then moved on, but now I’ll think…”Wow–that’s an interesting photo!” Like this one. The people look so tiny…somewhat unreal. It’s located in San Francisco, California. Lots of squares and angles.
I love the old blended with the new and the varying shades of blue of this statue and building in Lexington, Kentucky! Again…lots of squares and angles.
Squares abound in this photo of a building in Louisville, Kentucky. And the colorful bicycles add interest!
The angle of this photo of Sacre Coeur in Paris is nice…I think. | https://travelspirit333.com/2013/03/12/cees-fun-foto-challenge-squares-and-angles/ |
How many different (martial) arts should you explore? Pick one and practice it over your lifetime to become the expert of experts? Switch frequently and try as many as you can to have the broadest possible perspective? I think the answer lies somewhere in the middle.
If you only ever study one art, chances are you will not fully understand it. If you get distracted by trying to do too many, then most likely you will not get anywhere with either one.
Avoid tunnel vision
While I strongly believe that you need to spend a lot of time on one art to really understand it, and maybe eventually even master it to some degree, it also limits your perspective to a problem and its solution to only one single angle.
I often noticed, that I would understand things on a deeper level, when they were presented to me from different angles. Sometimes the Karate explanation made more sense to me, sometimes it was the Tai Chi approach and sometimes I would finally understand a difficult principle while trying to practice an Aikido move or Jodo strike.
Don’t miss the tree for the forest
On the flip side you need deep and enduring exposure to a certain framework of thinking or philosophy, to understand it on a natural level, to feel it. To “make it yours” (Morihei Ueshiba).
So if you try to learn too many different things at the same time, it will distract you more than it will help. It’s hard to combine teachings from external arts like Karate with internal systems like Tai Chi if you didn’t get to the level of seeing the principles yet. It will all just seem like a big mess of disconnected contradictions.
Know your core and expand from there
Start by picking one martial art. Practice it. Practice some more. Keep practicing until you reach a level where the underlying principles start revealing themselves and until you don’t have to ‘think’ about the movements anymore.
Then go and add small doses of other styles and arts to it. Observe what that teaches you. See what new angles and perspectives open up for problems that you already worked on (and maybe struggled with). Be open to understand moves that you have already practiced from a new and different angle. Don’t rip and replace, rather add to your knowledge.
You might shift your primary art over time as your interests change, but always have a primary art that you go deep on and see others as supplements.
If you experiment with other arts, I would recommend to seek significantly different perspectives. If you do Shotokan Karate, don’t do Wado Ryu. It will teach you a master’s preferences, but only few new insights. Add something different like Aikido or Tai Chi. If your focus is an external martial art (like Karate, Kung fu, Tae Kwon do, etc) then add an internal art (like Aikido, Tai Chi, etc) and vice versa.
Dip your toes into something new. Try it out long enough to get a good sense for the ideas and principles underneath, but know your home base. Know your core and expand from there. | https://blogs.keruumabudo.com/2018/09/22/how-many-arts-should-you-explore/ |
Use your imagination as diving gear as you swim down deep to the ocean floor.
1.
Watch videos of underwater explorations, look at photographs and other artwork such as <i>Swimmy</i>, and gather information about the ocean's topography and life. Introduce vocabulary words (coral, anemone, tides).
2.
Using imagination as diving gear, dive to the ocean floor. Glide into undersea caves, through coral reefs, ocean canyons, and over mountain ranges. What forms of life are there? What does the bottom of the sea look like?
3.
Cover the work area with recycled newspaper. Use scrap paper to try various watercolor techniques, including these.<br><li><i><b>Sponge painting.</i></b> Dampen the paper with a clean sponge. Use other sponges to apply Crayola® Washable Watercolors. Tip the paper to blend and mix colors.<li><i><b>Crystal patterns.</i></b> After applying watercolors with Crayola Paint Brushes, sprinkle salt on the wet paper. Watch crystal-like patterns form. When dry, brush off dried salt.<li><i><b>Spatter paint.</i></b> To create wispy, irregular dot patterns, scrape a small piece of stiff cardboard over a stiff, paint-laden brush. Or use a small piece of screen with the edges taped for safety.<li><i><b>Straw painting.</i></b> Blow a large dot of thinned watercolor with a straw held at a low angle to create irregular, spidery designs. Try holding the straw at different angles to achieve other effects.
4.
On a large piece of watercolor paper, use the selected watercolor techniques to add color and texture in creating a sea environment. For details, use a fine brush tip. Air-dry.
5.
For additional textures, use Crayola Scissors to cut (or tear) shapes from the dry experimental papers and glue them to the dry background with Crayola Glue Sticks.
6.
Add details with Crayola Fine Line Markers.
Send a postcard from space to show what you know about the other planets.
Remember the compliments you’ve heard from others—and get to know your friends better—with this 3-D self-portrait.
How do you use water, every day or for fun? With your classmates, create a book about why water is important to each of
What could you do when you were 6 months old? When did you first walk? Make this pop-up record of your growing-up milest
Pigs are big in children’s literature! Choose a favorite porker, maybe from <em>Charlotte’s Web</em>, and make a colorfu
What does your face look like when you taste something sour? Or smell something delicious? Create an expressive, decorat
Use Crayola® Gel Markers to add a colorful diagram to a report on the natural cycles of the solar system.
Use alliteration in fantasy animal poetry then create a drawing using letters to form patterns and textures.
Our crayons have been rolling off the assembly line since 1903. | http://www.crayola.co.uk/lesson-plans/undersea-adventure-lesson-plan/ |
Another great week has gone by at our after school photography clubs and this week the children had an exciting new challenge. They were given the theme of “perspective” and, to help them understand and encourage them to take photographs from different angles, they were all given a toy dinosaur to work with and take on an adventure. The idea was for them to use different perspectives to make the dinosaur look big, or small, and get them splashing around in the mud or climbing up a tree.
Have a pre-historic adventure of your own this half-term by visiting the Natural History Museum in London!
Next week is half-term for our children’s photography workshops, but when we’re back be sure to check out our new theme “shapes and textures”, where the children will have the challenge of making sure their shots are in focus!
You can see some of the best shots from this week below and to check out photos from our previous photography courses for children head to our Gallery.
Follow us on Facebook, Twitter and Instagram for regular updates. | https://sharpshotsphotoclub.co.uk/perspectives/ |
This Domain-Level Guide is designed to be used based on the Core Model. Please refer to the Feel Doubt — Welcome Ambiguity Core Practice before exploring this guide.
overview
Decisions drive organizations forward. When decisions are delayed indefinitely, the team is either stuck in place or randomly takes steps that do not align toward a consistent direction and a shared vision. At the same time, when decisions are premature, undebatable, or cannot be challenged and reconsidered, the impact on organizational Creativity could be devastating.
A creative organization must constantly balance the need to make decisions, set a clear path for the next steps, and being open to different opinions and perspectives. Feeling Doubt and Utilizing Ambiguity create opportunities for creative insights to emerge. Some of them will influence your decisions. But even if they don’t, they make the team open-minded and alert, so decisions can evolve and be changed dynamically.
guide
Invite Different Opinions Proactively
The human mind tends to favor the known and familiar. We are biased toward information we already know and opinions we already have. When making a decision, this tendency might make you miss opportunities by not seeing (or valuing) different options.
One way to overcome such a blind spot is to proactively invite more people to share their opinion before making a decision. The more diverse the group is, the more surprising and insightful the different views will be. Their implicit or explicit impact on the decision is guaranteed.
- No matter how confident you are when making a decision, proactively invite other opinions and perspectives.
- Invite people from different disciplines, domains, and teams to share their unique points of view. The farther they are from the original context of the challenge you are facing, the more surprising their perspectives are.
- Genuinely consider the different perspectives before making a decision and after the decision has been made.
Let Different Options Sink In Before Making a Decision
Inviting Different Opinions is obviously a mandatory step if you wish to proactively create doubt. But to be effective and allow these opinions to influence your decision, you have to make space for the different perspectives to sink in.
Organizations often aim for quick decisions. The need for immediate response must be balanced with allowing time for the different perspectives to impact your view on the dilemma and the various decision paths.
- Don’t rush into making a decision before coming up with different options.
- Let the different options sink in. Let them make the dilemma, as opposed to the solution, clearer.
Invite Dilemma Where it is Not Apparent
When a dilemma is apparent and acknowledged, it is easier to Invite Different Opinions and let them sink in. Many decisions, however, are implicit. In these cases, we operate based on inertia, or we don’t even realize the existence of other options. Hence there is no explicit dilemma and no meaningful discussion.
Great opportunities lie in questioning the things we do by default. Turning these implicit decisions into explicit discussions will allow you to invite different views and options and potentially identify and pursue new opportunities.
- Notice the situations you consider “no brainer” or “more of the same.”
- Reflect on them and try to see a dilemma in them.
- Consider different alternatives and their potential impact on the default mode of operation.
- Experiment with some of them.
examples
Example 1
When facing a dilemma, no matter how small, record it and the various options. Record also your decision. If the decision has a long-lasting effect (for example, on how you operate), revisit the decision and proactively add new pieces of information or new perspectives. Invite other people to share their views and challenge the decision from time to time. Allow yourself to change the decision if you see an opportunity in it.
Example 2
Present dilemmas that are confined to the scope of your team to people outside of the group. Invite them into the discussion and ask them to share their perspective even if they are unfamiliar with all the details.
You can turn this practice into an organization-wide practice by always saving seats for “visitors” beyond the direct stakeholders of an activity. | https://creativityos.com/model/org-domain-guide/wonder/feel-doubt-welcome-ambiguity/ |
The 182-metre-tall statue of Sardar Vallabhbhai Patel has another high point to it; what is believed to be the world's tallest statue is now visible from space.
A clear shot of the Statue of Unity in Gujarat was captured from space by a commercial satellite network Planet. The angled SkySat image was captured on November 15, 2018.
The image from the space clearly shows the structure revealing itself and towering over the Narmada River.
At 597 feet, India’s Statue of Unity is now the tallest statue in the world and clearly seen from space! Oblique SkySat image captured today, November 15, 2018. pic.twitter.com/FkpVoHJKjwPlanet (@planetlabs) November 15, 2018
The Statue of Unity has joined the league of man-made structures visible from the space. Famous structures captured from Low Earth Orbit have always fascinated people around the world.
One of them is the ancient Pyramids of Giza in Egypt. One of the Expedition 40 crew members aboard the International Space Station (ISS) captured the photo below.
Up for another one?
Man-made archipelagos near Dubai, United Arab Emirates (UAE), are featured in this image photographed by an Expedition 39 crew member on the International Space Station, flying at 350 km above Earth.
STATUE OF UNITY
Prime Minister Narendra Modi dedicated to the nation a 182-metre-tall statue of Sardar Vallabhbhai Patel, believed to be the tallest in the world.
The imposing monument is twice the height of the Statue of Liberty in the US and is built on an islet, Sadhu Bet, around 3.5 km downstream from the Sardar Sarovar Dam in Gujarat's Narmada district.
In his speech, Modi stressed that the statue would generate immense employment opportunities for the local tribals living near the dam in Narmada district.
Gujarat's governor OP Kohli, Chief Minister Vijay Rupani and Bharatiya Janata Party (BJP) chief Amit Shah were also present at the unveiling of the Statue of Unity. | https://www.indiatoday.in/science/story/statue-of-unity-worlds-tallest-visible-space-photo-satellite-1390115-2018-11-16 |
What are the best Mayan Ruins in Mexico to Visit?
1. Tulum
Tulum is a Maya site in Mexico’s Quintana Roo region dating back to between the 13th and 16th centuries. At its peak, Tulum was quite a thriving walled city.
Whilst relatively modest in comparison to, say Chichen Itza, Tulum does feature some interesting and quite well preserved ruins, including its castle, city walls and temples. One of the highlights at Tulum is its Temple of the Frescoes, with some original frescoes inside it. However, the real beauty of Tulum is its shimmering beachside location.
2. Chichen Itza
Stunningly well-preserved and imposingly beautiful, Chichen Itza is one of Mexico’s most impressive historical sites and includes the world famous, looming Mesoamerican step-pyramid known as El Castillo. A UNESCO World Heritage site based in the forests of the Yucatan Peninsula, Chichen Itza is actually made up of two cities built by two peoples, the Mayas and the Toltecs. The site is made up of several surviving buildings including a circular observatory known as El Caracol, the Warriors’ Temple and El Castillo.
3. Uxmal
Uxmal might not be as well-known as other Mayan tourist attractions in Mexico, but that doesn’t make it any less impressive. This Maya town was thought to have been inhabited as early as 800 BC and would once have been a thriving city and important religious centre. At its peak as many as 25,000 people lived here. Amongst its most striking structures is the “House of the Magician”, a looming one-hundred-foot high monument. Unfortunately (or perhaps fortunately?) visitors are banned from climbing to its top. With its location in the hilly and immensely scenic Puuc region, Uxmal easily ranks as amongst the top 10 sights in Mexico.
4. Calakmul
Calakmul is a remote and incredible Maya site in Campeche, Mexico, containing the remains of a vast and once-powerful ancient city. Extremely remote, the site has few if any tourists and offers an incredible experience to those willing to make the journey to explore its ancient remains.
A major rival to the city of Tikal, the two powers fought for control throughout the sixth and seventh centuries AD. At its height it was thought to have had estimated to have a population of 50,000. However, as with many cities in the region, Calakmul was slowly abandoned with the collapse of Maya power.
Once comprising of thousands of buildings and other structures, even today Calakmul is only partially excavated. However, these ruins contain huge pyramids, temples and other structures which are truly awe-inspiring to behold.
5. Cobá
Cobá houses the remains of a once vast city that developed in around 632 AD and peaked between 800 and 1100 AD. Whilst it is thought the city originally spanned a massive 60 square kilometres, the current archaeological site has yet to uncover all its remains. Among the sites to explore are a large holy pyramid called the Temple of the Church, a playing field used to play ball games and of course the Great Pyramid, also known as the Nohoch Mul Pyramid. Rising to a height of 138 feet, the Great Pyramid is the second tallest of all Maya pyramids in the region. Climbing the steep stairs of this pyramid can be daunting, but the views are great.
6. Chacchoben
Chacchoben is a Maya site in Mexico housing some impressive pyramid temples. A popular tourist site, several tour companies operate here.The exact history of Chacchoben is unclear. Most sources date its pyramids to around 700AD, although the Maya are said to have been present at Chacchoben long before this, perhaps as early as 200BC.
7. Palenque
In the heart of the jungle and containing some fascinating sites, the Maya settlement of Palenque ranks amongst the most impressive historic cities in Mexico. Some of the most fascinating sites in Palenque include the Temple of the Inscriptions, the Palace and several other temples, such as the Temple of the Sun and the Temple of the Cross. Each of the structures in Palenque is ornate and lavishly decorated, bearing inscriptions chronicling the history of the city, which was probably the capital of the region.
8. Yaxchilan
Hidden away far from the husstle and busstle of the main tourist track is the archeaological site of Yaxchilan, containing the ruins of this once-powerful Maya city. The ruins are found along the Usumasinta River and a selection of local tour operators offer boat trips to the site.
Today the ruins contain an incredible set of palaces and temples as well as an array of smaller remains which spread out over a wide area. Not a place for the faint hearted, Yaxchilan is nevertheless a fascinating place to explore.
9. Ek Balam
Boasting a number of impressive Maya temples and other buildings, Ek Balam is a Maya site on the Yucatan Peninsula. The amazing central pyramid rises to almost 100 ft. Translated either as Black Jaguar or Star Jaguar, Ek Balam is surrounded by a low, stone wall, an unusual feature in Mayan cities. Within this area are several restored pyramids and large temples as well as a ball court. The site’s vast main pyramid rises to a height of almost 100 feet, making it a remarkable example of Maya engineering.
10. Kabah
Kabah was a Maya settlement and is now an archaeological site in Mexico’s Yucatan state. Inhabited from the third century BC and, like nearby Uxmal, abandoned in circa 1200 AD, Kabah was mostly constructed from the seventh century and added to in the ninth century. It is thought that Kabah was linked to the site of Uxmal – indeed the two are connected by a road - and, whilst it does not boast the grandeur of this larger settlement, Kabah’s ruins are interesting in their own right. One of Kabah’s most impressive sites is its Temple of the Masks, so called for its many depictions of the rain g-d, Chaac, who is also a central figure in Uxmal. | https://www.triphistoric.com/explore/articles/breathtaking-mayan-ruins-in-mexico |
The KVLY-TV mast (formerly the KTHI-TV mast) is a 2,063-foot-tall (629 m) television-transmitting mast in Blanchard, Traill County, North Dakota, United States, used by Fargo station KVLY-TV channel 11. Completed during 1963, it was the tallest structure in the world until succeeded by the Warsaw radio mast during 1974, which collapsed in 1991, again making the KVLY-TV mast the tallest structure in the world until the Burj Khalifa exceeded it in 2008. It remains the fourth-tallest structure in the world (since the construction of the Tokyo Skytree and the Shanghai Tower), the tallest structure in the Western Hemisphere, and the tallest radio mast in the world.
The mast is located 3 miles (4.8 km) west of Blanchard, North Dakota, halfway between Fargo and Grand Forks. It became the tallest artificial structure, and the first man-made structure to exceed 2,000 feet (610 m) in height, upon the completion of its construction on August 13, 1963.
The tower was built by Hamilton Erection Company of York, South Carolina and Kline Iron and Steel, and required thirty days to complete, at a cost of US$500,000 (roughly $4 million today).
Owned by Gray Television of Atlanta, Georgia, the tower broadcasts at 356 kW on channel 44 for television station KVLY-TV (channel 11 PSIP, an NBC/CBS affiliate) which is based in Fargo. The tower provides a broadcast area of roughly 9,700 square miles (25,000 km2) which is a radius of about 55.6 miles (89.5 km).
When the mast was built the call letters of the television station for which it was built were changed to KTHI, the "HI" referring to the height of the mast. The top is reachable by a two-person service elevator (built by Park Manufacturing of Charlotte, NC) or ladder.
The tower consists of two parts: a lattice tower of 1,950 feet (590 m); topped by a transmitting array of 113 feet (34 m). The total height of both is 2,063 feet (629 m). The antenna weighs 9,000 pounds (4.3 tons; 4,300 kg), the lattice tower weighs 855,500 pounds (388 tons; 388,000 kg), giving a total weight of 864,500 pounds (392 tons; 392,100 kg). It takes up 160 acres (0.65 km2) of land with its guy anchors. Its height above mean sea level is 3,038 feet (926 m).
Some time after its completion, the Federal Communications Commission (FCC) and Federal Aviation Administration (FAA) imposed a policy that states, "Although there is no absolute height limit for antenna towers, both agencies have established a rebuttable presumption against structures over 2,000 feet above ground level." The FCC and FAA may approve a taller structure in "exceptional cases." | http://www.theinfolist.com/php/SummaryGet.php?FindGo=KVLY-TV_mast |
Real estate is basically property consisting of the buildings and land on it, together with its accompanying natural resources like water, plants or minerals; and its value derived directly or indirectly from these resources. In layman’s terms, real estate is any property one owns that belongs to another person. That would include real estate owned by a person directly, like his personal home or his business establishment, and those held jointly by individuals or entities, like a mortgage or a partnership agreement. Real estate may also be defined as a portion of land considered as usable according to normal business rules of that specific part of the world.
One can divide the world of real estate into two categories: man-made and natural. Man-made real estate includes those constructed by man, like skyscrapers and bridges, and all the accompanying technologies required for its construction, whether by humans or machines. On the other hand, natural real estate is land that comes from nature, like forests or mountains, and is developed upon the topography. It is not entirely man-made, as many types of man-made structures also come from nature. Natural real estate, on the other hand, excludes man-made constructions, like factories.
A major portion of real estate today deals with the improvement and construction of physical structures. Most of the physical properties we see around us originated through man-made means, and over time their improvement has led to the creation of vast man-made networks of roads, sewage systems, electrical power grids, telephone and cable lines, etc., all of which have led to the modern world we inhabit today. The improvement of infrastructure around the globe has led to the opening up of vast new economic opportunities for the people of developing countries. Achieving development in infrastructure requires vast investments in terms of time, money, effort, labor, materials and technology; therefore, the development of such properties as buildings, etc., plays a key role in overall economic conditions. | https://spacehosteltokyo.com/economic-characteristics-of-real-estate/ |
Known as the home of great religions, in addition to its simple natural beauty and magnificent palaces, India also attracts a large number of tourists who buy flights to India. India is a country where international tourists will admire the majestic grandeur of these sacred temples.
Taj Mahal
Built from 1632 to 1653, the Taj Mahal is considered one of the seven famous man-made wonders in the world, as well as a famous tourist symbol of this country.
The temple located in the city of Agra is a combination of the Western and Islamic styles of the Agra fortress or Fatehpur Sikri citadel. In 1983, the temple was recognized by UNESCO as a World Heritage Site.
Swaminarayan Akshardham Temple
Located in New Delhi, Swaminarayan Akshardham is known as one of the largest Hindu temples in the world. A unique work bearing the imprint of the culture and history of the country of India.
Here you will be overwhelmed with a large exhibition complex of ancient Indian architecture and traditions through its architecture, galleries, gardens, water music, and a ship.
Meenakshi Amman Temple
Talking about the sacred and famous temples in India, it is impossible to ignore the name Meenakshi Amman. This is one of the most important temples of India, located in the holy city of Madurai.
Built in the early 17th century, Meenakshi Amman is dedicated to Sundareswar (mother of God Shiva) and Meenakshi (mother of Goddess Parvati). The highlight of that temple is the 14 magnificent towers including both Gopurams for the main gods, elaborately sculpted and painted.
Brihadeeswarar Temple
Located in the city of Thanjavur, in the state of Tamil Nadu, Brihadeeswarar temple was built by King Rajaraja Chola I in the 11th century. Upon completion, the work is recognized as the first granite temple in the world.
Coming here, you will feel every breath of the Hindu architectural style, including intricately carved walls, eye-catching patterns, and harmonious color combinations. Especially with a height of 66 meters, Brihadeeswarar is one of the tallest temples in the world. | https://visitindiaonline.net/explore-india-through-many-famous-temples-of-this-country-part-1/ |
particular, do not approach their regional maximums in the park,
and
lowland species like sycamore and cottonwood reach more
impressive heights.
In South Carolina, the tallest species different regions of the
state
ensure some of the tallest species of the state stay well
separated, so no
one site can achieve the dominance of some of the northeastern
sites.
Compounding that divide is the fact that the best conifer and
broadleaf
sites in the mountains do not coincide. In spite of those
considerations,
the central section of the Brevard Belt still comes within 10%
of the
state Rucker Index. That situation highlights the fact that the
second-tier tall species are not that much shorter than the
tallest group
of species. 15 feet may seem like a great height difference, but
that
length is still less than 10% of the height of the tallest
species.
North
Carolina has great tree diversity and distinct physiographic
provinces, so the dominance of the Smokies appears to contradict
the
pattern established in looking at the other sites. I attribute
part of
the dominance simply to the fact that the Smokies are a special
area.
Lack of disturbance, and lack of continued disturbance, climate,
geology,
and the resultant high diversity all work in favor of the site.
The other
part of the smokies dominance is probably an artificial artifact
of how we
have set up the situation. The NC side of the park contains
several
distinct high growth areas that are separated by areas of
shorter forest
with different growing conditions, and the high growth regions
are spatial
separated by a few miles. If not for the park boundary, we would
probably
see the area as having several distinct superlative sites rather
than one
large, incomparable site. The other human factor is the paucity
of data
we have form the NC piedmont and costal plain. Will Blozan has
just
recently found one excellent piedmont site giving a specific
example of
the regions potential. How tall can sweetgum, loblolly pine,
cherrybark
oak, and shumard oak grow in the state's floodplains.
Zoar
Valley's dominance in New York points to some holes in this
theory
and the spectacular nature of the site. New York has several
distinct
regions, yet Zoar Valley appears to include excellent habitat
for all of
the tall hardwood species in the state. The lack of conifers
makes the
sites dominance more impressive, but reinforces the fact that
the second
tier of tall species really is not that much shorter than the
tallest
group of species.
Enough half thought through rambling. | http://www.nativetreesociety.org/fieldtrips/south_carolina/south_carolina_sites.htm |
A Sea Of Red In Larung Gar: Tibet
Larung Gar Monastery is located in Larung Valley and it is under Serta County of Garze Tibetan Autonomous Prefecture in Sichuan, China. From the...
Fethiye: Turkey’s Turquoise Coast
Fethiye is one of Turkey's well-known tourist centres and is especially popular during the summer. Fethiye is a tourist town with an international atmosphere....
Most Peaceful Countries in the World
The study assesses world peace through three filters: safety and security in society, the extent of the ongoing national or international conflict, and the...
Rainbow Mountain in Peru
Rainbow Mountain, is a mountain in the Andes of Peru with an altitude of 5,200 metres above sea level. Elevation: 5,200 m Range: Andes Rainbow...
Seven Summits: Top Of The World
The "Seven Summits" include the tallest mountains on each of Earth's seven continents: Everest, Aconcagua, Denali, Kilimanjaro, Elbrus, Mount Vinson, and the Carstensz Pyramid....
Hidden Gems in India
Here is a list of the best unexplored places in India that have a surprise for everyone to indulge and have a great time...
Lake Powell: Man-Made Reservoir
Lake Powell is a man-made reservoir on the Colorado River in Utah and Arizona, United States.Glen Canyon Dam was built to regulate water availability...
Where The Wind Doesn’t Stop: Faroe Islands
The Faroe Islands are a small archipelago of 18 rugged and rocky islands in northern UK and southwest Iceland. The island group is an...
Mussoorie: A Place For Peace
They say there is a time during the daily sunset ritual when the world is silent. The birds stop chirping, the wind seems to...
World’s Great Mountains And Hiking
The tallest mountain in the world, Everest is probably beyond your reach unless you have perfect experience and $ 50,000 to spend. But you... | https://traveology.com/category/holiday-themes/friends/ |
This is a list of the tallest buildings in the world. This means that the list only include man-made structures that are meant for living in or office work, and does not include towers like radio towers or observation towers. For a list of the tallest towers in the world – click here (this list was last updated in June 2016) 1. Burj Khalifa...
Category - Engineering & Architecture
Engineering and architecture related posts: Man made structures, buildings, transportation and more
The world’s longest suspension bridges are listed according to the length of their main span which is the length of suspended roadway between the bridge’s towers. 1. Akashi Kaikyō Bridge, Japan Main span of 1,991 meters (6,532 ft) – opened in 1998. Links the city of Kobe on the mainland of Honshu to Iwaya on Awaji Island. Its... | https://10mosttoday.com/category/engineering-and-architecture/page/6/ |
It’s been two decades since we stepped into the 21st century and till now, architecture took it’s twisted turns too. Architecture has changed a lot, in its own definition too. Be it Colosseum, an ancient Roman amphitheater constructed in 70-80 AD or Guggenheim Museum Bilbao, contemporary art museum covered in shiny sheets of metal inaugurated in 1997. Both are of the totally different era, construction materials, techniques and are also one the unique buildings in the world. While discussing the great architecture of the world, we will also keep in mind the constant change that is happening in this field and most famous buildings in the world.
Our list of famous buildings of the world is assembled in the attempt to bring you a bit closer to the historical and the modern traits of what makes the famous architecture.
1. Angkor Wat – Cambodia
It is one of the largest religious and mysterious monuments in the world. It was transformed to Buddhist temple from Hindu temple at end of 12th century. It is as impressive as it is vast, making it a brilliant example of Khmer architecture. It is admired for the grandeur and harmony of the architecture although it just combines two basic plans of Khmer temple architecture: the temple mountain and the later galleried temple.
2. Hagia Sophia – Istanbul
The present standing building was constructed originally as a church between 532 and 537 on the orders of the Byzantine Emperor; therefore, it is also a singular testimony to the grandeur and the genius of Byzantine architecture. It is the former Greek Orthodox Christian patriarchal cathedral, later an Ottoman imperial mosque and now a museum in Istanbul, Turkey.
3. Forbidden City – Beijing, China
The Forbidden City is the world’s largest collection of well-preserved medieval wooden structures; every detail reflects features of traditional Chinese architecture and rich Chinese culture. It was constructed from 1406 and opened for public in 1420. The complex consists of 980 buildings and covers 72 hectares. Such structures give us an idea about the great architecture of the world.
4. Château de Chenonceau – Chenonceaux, France
It is a French château (a large French country house or castle, often giving its name to wine made in its neighbourhood) spanning the River Cher. The current château was built in 1514–1522 on the foundations of an old mill and was later extended to span the river. The bridge over the river was built in 1556-1559, on the basic designs of French Renaissance architecture.
5. Flatiron Building – New York City, New York
It is originally known as the Fuller Building. It is a triangular 22-story, 285-foot (87 m) tall steel-framed landmark building. It was completed in 1902 and has been called one of the world’s most iconic skyscrapers of that time, being the tallest. As with numerous other wedge-shaped buildings in the neighbourhood, the name “Flatiron” derives from its resemblance to a cast-iron clothes iron. The Flatiron Building was designated a New York City landmark in 1966
6. The Gateway Arch – St. Louis, Missouri, USA
The Gateway Arch is a 630-foot monument and it is the world’s tallest arch. It is Clad in stainless steel and built in the form of a weighted catenary arch. There was a design competition for this piece of work for 3 years 1945-48, though it was complete in 1965 and officially dedicated to “the American people.
7. Kauffman Residence or Falling water – Pittsburgh, Pennsylvania
It is a masterpiece designed by Frank Lloyd Wright and built in 1935. It is a famous modern architecture example, a house which is a fusion of the artificial and the natural in perfect harmony. This house is set above a natural waterfall and water is actually flowing through it. It was declared “best all-time work of American architecture” by the American Institute of Architects in the year 1991.
8. Burj al Arab – Dubai
Burj al Arab is 321 meters high and it represents one of the wonders of contemporary engineering in today’s world, completed in 1999. It is built on an artificial island 280 meters away from the coast. It has a helipad near the roof at a height of 210 m (689 ft) above ground making it is one of the most luxurious and the fourth tallest hotel in the world.
9. Metropol Parasol – Spain
Metropol Parasol is a wooden structure, some 90 feet high and nearly 500 feet long. The structure consists of six parasols (A parasol is an object like an umbrella that provides shade from the sun) in the form of giant mushrooms constructed in four levels. The wood used in the structure is birch, imported from Finland, because of its straight qualities and it was completed in 2011.
10. Gardens by the Bay – Singapore
It is a nature park, created in 2012. Gardens by the Bay is Singapore’s plans to transform its “Garden City” to a “City in a Garden”, with the main aim of raising the quality of life by enhancing greenery all around and flora in the city. The park consists of three waterfront gardens: Bay South Garden, Bay East Garden and Bay Central Garden. Its flower Dome is the largest glass greenhouse in the world. It can be considered as one of top 10 coolest buildings in the world
Ironically there is a book “great architecture of the world” by John Julius Norwich published in 1975. It covered all the famous architectural buildings created by mankind by then, from the point of view of fourteen of the most distinguished architectural historians. It has more than 800 original diagrams, annotated drawings, and photographs. This book can actually help you for a better understanding of the different design processes of architects of that period.
All the buildings/structures listed above are totally different from each other in every aspect. As every architect has a different thinking process as well as every architect is trying to achieve something different in each building. No two buildings are ever the same, even if they are adjacent to each other. In the present time, where every architect is trying to be Best architect in the world 2018, we first need to connect and learn from the “great architecture of the world”; and carry out our design process accordingly. | https://architecturechat.com/blog/great-architecture-of-the-world/ |
What country has most of the tallest buildings?
Countries
|Number of Buildings|
|Rank||Country||300m+|
|1||China||95|
|2||United States||28|
|3||United Arab Emirates||31|
Where is the 2nd tallest building in the world?
Tallest Buildings
|Rank||Name||City|
|1||Burj Khalifa||Dubai|
|2||Shanghai Tower||Shanghai|
|3||Makkah Royal Clock Tower||Mecca|
|4||Ping An Finance Center||Shenzhen|
What country has half of the world’s tallest buildings?
In fact, the 10 tallest structures worldwide have been completed in the last 15 years, starting with Taiwan’s Taipei 101 in 2004, according to the Council on Tall Buildings and Urban Habitat. China alone has built half of the top 10 highest towers, and One World Trade Center is the only U.S. building to make the list.
What will be the tallest building in 2020?
When the 3,280-feet-tall (1,000-meter-tall) Jeddah Tower, in Saudi Arabia, opens in 2020, it will knock Dubai’s iconic Burj Khalifa off its throne as the tallest skyscraper in the world by 236 feet (72 meters). Construction of the landmark is estimated to cost $1.4 billion.
Why are there no skyscrapers in Europe?
Most of Europe’s cities around that time were also more evenly zoned and were not facing the high demand for floor space in key districts that typically drive high rise development. Above: European cities were much more established and evenly zoned when skyscrapers first rose to prominence.
Which building has the most floors?
Completed buildings
|Rank||Structure||Floors|
|1||Burj Khalifa||163|
|3||Shanghai Tower||128|
|4||Goldin Finance 117||128|
|5||Lotte World Tower||123|
Is Burj Khalifa taller than Mount Everest?
At 2717 feet, this 160 floor building is HUGE. But, of course, there are many things on Earth that are a lot bigger. For example, the tallest mountain in the world: Mount Everest. … As we discovered yesterday, at 2717 feet the Burj Khalifa is just over 0.5 miles high.
What will be the tallest building in the world in 2050?
Called the Jeddah Tower, the building will serve as the centerpiece for a larger redevelopment called the Jeddah Economic City.
What is the tallest animal in the world?
The giraffe is the tallest animal on Earth.
Formally known as Giraffa camelopardalis, the average giraffe stands 14 to 19 feet (4.3 to 5.8 meters) tall, according to National Geographic. Most of a giraffe’s height comes from its famously long neck, which can extend almost 7 feet.
Is Eiffel tower taller than Empire State Building?
The Eiffel stands at 1,063 ft from base to tip, the Empire State Building is 1,250 ft (1,454 ft if you include the antenna) Eiffel Tower is taller.
What building is 1000 feet?
Tallest man-made structure in the world from 1930 until 1931; First building to be more than 1,000 feet tall; tallest brick building in the world. Also known as the Times Tower.
What is the tallest hotel in the world?
again. (CNN) — In 2018, the 356-meter (1,168 feet) Gevora Hotel in Dubai became the tallest hotel in the world, complete with certification as a Guinness World Record.
What is the shortest building in the world?
The world’s shortest building is called the Newby-McMahon Building, in Withita Falls, Texas. It stands 40 feet tall.
How tall we can build?
But according to Baker, it’s entirely possible. “You could conceivably go higher than the highest mountain, as long as you kept spreading a wider and wider base,” Baker says. Theoretically, then, a building could be built at least as tall as 8,849 meters, one meter taller than Mount Everest.
How tall is the biggest building in the world?
World Records
At over 828 metres (2,716.5 feet) and more than 160 stories, Burj Khalifa holds the following records: Tallest building in the world. Tallest free-standing structure in the world. Highest number of stories in the world. | https://the-biggest.net/people/what-country-has-the-15-tallest-buildings-in-the-world.html |
Cascate delle Marmore
The waterfall at Marmore, located in Umbria, is the tallest man-made waterfall in the world. It was created by the Romans.
Located about 8km from Terni, the capital of the Italian province of Umbria, are the Cascate delle Marmore, or Marmore’s Falls. The waterfall here is the world’s tallest in existence, with a total height of about 165m. It actually consists of three sections, of which the one at the top is the tallest at 83m in height.
The waterfall was created by the Romans in 271 BC. The stagnant water in a nearby wetland area, fed by the river Velino, was the cause of frequent outbreaks of malaria in the town of Sabina. In an attempt to prevent further outbreaks, the Roman consul Curius Dentatus ordered the construction of a channel to divert the water off a cliff, thereby draining the wetland.
This meant that the water of the Velino River fed into that of the Nera River below. However, at times the rivers were so full of water that it caused the territory of Terni at the foot of the cliff became flooded. This was the cause of strife between the inhabitants of Sabina and those who lived at Terni, which never satisfactorily got resolved.Show For further details, refer to the website of the site.
Today, you can access the site either at the very top or at the very bottom, with ample parking space at both entrances. Stairs allow you to climb up or down with relative ease. Conveniently, there’s a shuttle bus available if you reach all the way down (or up) and don’t feel like taking the stairs back again to where you parked the car.
The water that normally flows off the cliff is at set times diverted to a hydroelectric power plant. The schedule is listed on the website of Marmore Falls. You can plan your visit to coincide with when the falls are switched on: an alarm sound will ring out from speakers when the water is about to be diverted over the cliff face.
Be prepared to spend a few hours at the site, since you shouldn’t rush up and down the steps. About halfway through, you’ll come across a man-made tunnel that leads to the balcone degli innamorati or “balcony of lovers”. This cuts straight through the mountain and offers a view from behind the waterfall.
If you go here while the water is at full force, be prepared to get wet! When we were there, it was quite hot, and some visitors had come prepared, donning swimming trunks or bikinis before going into the tunnel. We returned after the water had been switched off, but still got quite wet. But due to the heat, our clothes dried quickly.
The walk up and down the cliff is itself very worthwhile, if tiring. Aside from the spectacular views of the different falls and streams, the vegetation is green and pleasant, and the view of the surrounding hills and mountains is breathtaking. The water is also crystal clear; we drank some of it, and it was cool and refreshing.
All in all, the Cascate delle Marmore are definitely worth a visit. We visited the site early in the day and then travelled on to Spoleto, a town a little further to the north that is rich in ancient history. But obviously, I’ll write about what we saw there in a forthcoming article.
This article is part of the series, Exploring Umbria. | https://www.ancientworldmagazine.com/articles/cascate-delle-marmore/ |
Nature is full of beauty, there are countless things around the world which remind us about the beauty of the world we live in. Truly we live in a beautiful world and out of all these beautiful things, mountains is the one which has always fascinated mankind.
Throughout ages people have strived to get to the top of these mighty wonders of the nature. When ever we see them a thought runs into our mind that what would the world look like from the top and to make this imagination a reality countless mountaineers from around the world try to conquer some of the most dangerous summits.
This struggle to climb to the top also results in the loss of several precious lifes but then there is always pride when some one reaches the top and hoists the flag marking his success.
There are many mountains around the world but here I will compile only a list of those mountains which are the most famous and tallest ones:
Mount Everest
Mount Everest, as we all know is the highest mountains in the world it stands at a height of 8,848 metres.
The mountain is a part of the Himalayas range which is famous around the world for the height of its peaks and the beauty of them.
The first person the climb to the top of this mountains was Sir Edmund Hilary and after that other mountaineers followed using different routes which are even more dangerous.
K2 (Godwin Austen)
K2 is the second highest peak in the world. It is also known as Godwin Austen named after a local surveyor of the region.
The mountain stands tall at a height of 8,611 metres and is situated in the North of Pakistan. The peak is a part of the Himalayan range and is often classified to be the part of The Karakoram range which is a sub range of the Himalayas.
The mounatain is also called as "Savage mountain" because it is considered exteremly difficult to climb by the mountaineers and it is said that out every four person that try to climb it, one dies.
Kangchenjunga
This mountains is 3rd in the 8000 metres club it stands at a height of 8,586 metres. It is situated on the border line of India and Nepal and connects both the countries. The word "Kangchenjunga" implies 'five treasures of snow' and local people have some sacred belief about this five treasures.
The mountain was fist climbed by a British expedition and there is a tradition about this mountains that mountanieers don't got to the top instead come back a few steps short of the tallest point and this is done to honour the sacred belief about this mountain as held by the local population.
Lhotse
It is the fourth tallest mountain in the world. It is situated between China and Nepal. Its has a height of 8,516 metres and has two different summits with different heights which classifies it into three different summits.
The summit is also well known due to its connection with the Everest as it is connected to the Everest via South. The first person to reach the top of the summit was Fritz Luchsinger and Ernst Reiss who were a part of the team from Switzerland.
Nanga Parbat
Nanga Parbat is the 9th tallest peak in the world and is also a part of the Himalayan range. The reason why I disturbed the sequence was because of the beauty of this mountain and it was really worth mentioning in this list.
The Nanga Parbat is at a height of 8,126 metres above sea level it is well known for the difficulty in climbing it and therefore is considered extremely dangerous around the world by climbers. Nanga Parbat was first climbed by an Austrian named Hermann Buhl.
To summarize, the list is dominated by the peaks in the Himalayan Range which are known for their beauty and height. Not all the highest peaks have been included in the list as it would require several other pages to do so.
- Blue Mountains
Blue Mountains is one of the greatest tourist attraction which attracts so many visitors from around the world to visit and feel the majestic beauty of this natural mountainous region. The people who live in...
- Mountains And Famous Climbers
Mountains have always fascinated mankind. Their glorious heights, slopes and slippery features and stony structures have always been so captivating and intriguing. There's no wonder that people always wanted...
- List of highest mountains
Comments
More
More mountain talk
tell us more mountainssssssssssss
really thnx it helped a lot for my project
cool
thanks for it you is the greatest peole of the world
thankz 4 the gr8 info!
thanx for it
cool and good to know
i like mountains
thanks i'm saved from getting a detention now:D
I WANT TO SEE MOUNTAINS
Glad to see your hub about Mount Everest. I am from Mount Everest country, Nepal. The first person who climb Mount Everest was Tenzing Norge from Nepal. Tenzing Norge and Edmund Hilary climb the mount everest in 1953. There was a big controversy who climb first whether Tenzing Norge or Edmund Hilary. Tenzing Norge said he climb first and gave hand to Edmund Hilary to climb mount everest top. I am not writing who climb first I am writing because you missed to write about Tenzing Norge and Nepal.
I love Animal Crossing I hop i can meet stiches one day. THE MOUNTAINS ARE GREAT! One day i will try to climb one. They are so pretty me and my girlfriend are going on holiday to see one of the mountains. What a beautiful sight Hot girlfriend and cold, Beautiful Mountain Ranges.
great pic's! Thanks to you all i need to do is to look at this website, write whatever's on here and my homework's finished. By the way... i do own animal crossing and stiches has kk lulaby playing in his room...
thx i had a report on mountains andi got to finish it im 5th grae thanks a lot im sure i'll get an a+ any way they are so beautiful
wow i really enjoyed reading through this fascinating piece of work.
thankz
Thank you for the great article and photos. Did get to fly near Mt. Everest once many years ago. These mountains are very beautiful, especially, as you say, Nanga Parbat. Great hub. I also like Macchapuchre, or Fishtail Mt. in Nepal and Dhaulagiri.
Kool explanation and pictures.Thnx 4 it!!!!!!!!!!!!!!!!!!!!!!!!!!!
wow great pics....great hub...excellent explanation....thanx for sharing it...have a look for this one i am sure you will love it....
https://hubpages.com/technology/The-Nokia-888-Conc...
thanx
hi hassam i sure do like the nanga parbet it is so beautiful taht it reminda me of winter and those cold days with my boyfriend
heloo hassam sure like the pictures f the mountains becuse they make me think that how beautiful is the earth
really beautiful and very much helpful for preparing my assingments.
thankz
Hi Hassam, excellent photos. Feel like climbing the mountain rightaway. Simple idea, but truly very informative.Enjoy. God be with you.
hi Hassam, please see if you can also include Mt. mayon of the Philiipines. Thank you. God Bless!
I was thinking i could see Mount Kilimajaro on your list. Its excellent for adventure safaris in Africa. Even then, your list and preference is excellent.
Hi Hassam, you better post any Indonesian mountain too. Jayawijaya peak and Bromo are the sample. Do you want to see them closely?
The mountains are sure beautiful, hassam, but I wouldn't want to be one of those mountain cllimbers. I prefer just looking at the pictures from my nice, warm, comfortable easy chair. | https://hubpages.com/travel/Famous-Mountains |
Egypt is rich in ancient heritage and contemporary history, and the following 10 best places to visit there immerse travelers in cultural wonders and thrilling adventures.
Whether your focus is on the Pyramids of Giza or traveling between Aswan and Luxor on a Nile cruise, Egypt offers a world of treasures and diverse landscapes.
Visit tombs and temples, scuba dive the Red Sea, or amble through markets and mosques as you discover some of the best places to visit in Egypt.
Cairo captures the essence of a bygone era steeped in tradition and culture, with the famous Pyramids of Giza set just outside the city’s center.
Marketplaces buzz with activity, while mosques command attention. Cafes and a bustling high street bring Cairo into modern times, with museums and monuments honoring pharaohs and queens of the past.
Cairo is one of the world’s most fascinating mega-cities. Discover donkey carts and dusty lanes alongside the Nile’s vibrant riverbanks, as well as the connection to the heart of Umm al-Dunya, the Mother of the World, where you can see the seemingly endless achievements that make up Egypt’s vast timeline.
Highlights: Pyramids of Giza • The Egyptian Museum of Antiquities • Old Cairo • Khan el Khalili • The Hanging Church of the Virgin Mary • Al-Azhar Mosque • Souq Quarter
Recommended length of stay: 3-4 days
Luxor is more than a city. It has become one of the world’s greatest open-air museums, immediately immersing you in the past.
Few places in the world meet the grand scale and glamor of monuments that survive from ancient Thebes, including riches from temples and tombs. Options to view sites from a hot-air balloon give an aerial perspective of this ancient landscape.
Luxor sits on the banks of the Nile River, with boats bringing guests to experience the dramatic sights that make this Egyptian favorite a must-visit on Luxury Egypt Tours.
Highlights: Valley of the Kings • Karnak Temple • Valley of the Queens • Luxor Temple • Temple of Deir El-Bahri • Luxor Museum • Medinet Habu
Recommended length of stay: 2-3 days
The relaxed and friendly ambiance of Aswan contrasts the endless bustle of Cairo, revealing remnants that once acted as Egypt’s gateway to greater Africa.
You can experience the contrast of culture and heritage emerging from the relationship between Egyptian heritage and Nubian culture at the southernmost point of Upper Egypt. The Aswan High Dam provides electricity to inhabitants and is a marvel of engineering that’s worth visiting.
Colorful villages and beautiful gardens, accompanied by photogenic sunsets, add to the allure of the ancient temples and monuments.
Highlights: Elephantine Island • Nubain Museum • Temple of Philae • Aswan High Dam • Nubian Village • Monastery of St. Simeon
Recommended length of stay: 2-3 days
The quiet town of Abu Simbel hides in the shadow of two colossal temples cut deep into the rocks near the shores of Lake Nasser.
The region’s spirit is captured by their grandeur, but also stems from the enduring culture of the Nubian town, with its distinct cultural music.
It’s not hard to miss the magnificence of Ramses II’s monuments, which will immerse you in the pharaoh’s reign through colossal statues and graceful facades.
Highlights: Abu Simbel Temple Complex • Temple of Wadi El-Sebua • Colossi of Ramses II • Hypostyle Hall • The Sanctuary
Recommended length of stay: 2-3 days
Alexandria, a port city with Greek influences, remains a historic jewel of the Mediterranean, combining the ancient world with modern wonders.
Bygone alleyways lie under the modern city, hiding in the sea or stretching along the grand waterfront, with reminders of the Great Library and mighty lighthouse.
Formerly one of the largest cities in the world, the grandeur of Alexandria can be felt, while its beaches offer a chilled vibe in one of Egypt’s popular destinations for Egypt Family Vacations.
Highlights: Bibliotheca Alexandrina • Pharos of Alexandria • Alexandria National Museum • Fort Qaitbey • Corniche • Kom El-Dikka • Catacombs of Kom El Shoqafa
Recommended length of stay: 2-3 days
Hurghada, once a traditional village, now a contemporary powerhouse, represents the beauty of the Red Sea and the luxuries of Egypt’s coastal resorts.
An inescapable sheen spreads over the water and across the marina, giving way to some of the most impressive coral and marine life.
White-sand beaches, endless blue skies, and a connection to adventures on land and sea make Hurghada a delightful surprise that gives you a different perspective of Egypt’s beauty.
Highlights: Giftun Islands • Straits of Gubal • Hurghada Marina • Mosque El Mina Masjid • Bedion Communities • Beaches
Recommended length of stay: 3-4 days
Saqqara is in Lower Egypt, near the entrance to the Nile Delta, and was nominated as a World Heritage Site in 1979.
Steeped in history, one of its key features is the Djoser or Step Pyramid, one of the country’s earliest. Tombs unveil images of old kingdoms and burial sites hold a multitude of secrets from a bygone era.
Discover the stories behind this vast necropolis that served the former capital of Egypt, standing in stillness in the sacred space.
Highlights: Djoser’s Step Pyramid • Abwa el-Qotat sit • Old Kingdom Tombs • Mastaba el-Fara’un
Recommended length of stay: 1 day
Less than an hour’s drive from the capital city of Cairo lies Memphis, the former capital of Egypt. It is located at the entrance of the Nile River Valley near the Giza plateau.
This former key religious site was also a hub for trade and a popular excavation area, with discoveries such as an alabaster sphinx, the pylon of Ramses II, and the great temple of Ptah.
Marvel at the sheer magnitude of Ramses II in the indoor museum and take your time as you walk around admiring masterpieces in the popular outdoor museum on Egypt Tours for Seniors.
Highlights: Statue of Ramses II • Great Temple of Ptah • Temple of Hathor • Temple of Ptah and Sekhmet
Recommended length of stay: 1 day
A coastal gem on the Sinai peninsula, Sharm el Sheikh is a popular seaside destination for visitors looking to relax or dive, exploring nearby coral reefs.
Chic hotels invite visitors to enjoy views from rooftops or to dine in one of the many beachside cafes, absorbing the marvelous weather and relaxed ambiance.
Diverse marine life and long, sunny days make Sharm a popular tourist destination. Enjoy a stroll through the old town and visit St Catherine’s Monastery, while getting lost among the lights in this vibrant getaway.
Highlights: White Knight Dive Site • St Catherine’s Monastery • Ras Mohammed Peninsula • Farsha Beach • Windsurf at Nabq Bay
Recommended length of stay: 3-4 days
Between the desert and the Red Sea, Marsa Alam is one of Egypt’s south-eastern gems. It boasts healthy marine life and breathtaking reefs, popular with divers and snorkelers.
The town lies close to national parks and mountains, and serves as a wellness destination, offering a picturesque setting and tranquil vibe, its golden beaches providing the perfect playground for sunseekers.
From nearby mines to local fishing spots, Marsa Alam is a great addition to any Egypt itinerary.
Highlights: Abu Dabab Beach • National Park of Gebel Elba • Wadi al Gimal • Emerald Mountains
Recommended length of stay: 3-4 days
Egypt represents the depth and allure of Mediterranean culture, with must-see destinations committed to embracing its history. The country is an unforgettable adventure to ancient pyramids, once-hidden tombs, and vintage cruises down the Nile River.
You can visit our Egypt Travel Guide for more tips and helpful hints on how to create your perfect trip, and answers to many frequently asked questions can be found here. When you are ready to start planning Egypt Tours & Vacation Packages, you can speak with an Egypt travel specialist. | https://www.zicasso.com/a/egypt/ms |
Construction began on 21 September 2004, with the exterior of the structure completed on 1 October 2009. The building officially opened on 4 January 2010, and is part of the new 2 km2 (490-acre) development called Downtown Dubai at the 'First Interchange' along Sheikh Zayed Road, near Dubai's main business district.
CLICK IMAGE TO VIEW FULL SCREEN
Burj Khalifa compared with some other well-known tall structures
Burj Khalifa (Arabic: برج خليفة, "Khalifa Tower"), known as Burj Dubai prior to its inauguration, is a skyscraper in Dubai, United Arab Emirates, and is the tallest man-made structure in the world, at 829.8 m (2,722 ft).
Thus, competing in the construction of tall buildings is one of the signs of the Day of Judgement. In a hadith recorded in Sahih Muslim, Rasul Allah (sal Allahu alaihi wa sallam) told us that “you shall see barefoot, naked, penniless shepherds vying in constructing high buildings.” This hadith describes people who become rich all of a sudden and then build not for need but only in competition. | http://www.myminaret.com/2014/09/burj-khalifa-tallest-man-made-structure.html |
Over time, all life forms evolve, and evolutionary biology focuses on how that evolution happens. Changes in an organism's observable qualities cause changes in its genetic makeup, which is how populations of living things evolve. Mutations in an organism's DNA are one type of genetic alteration produced by damage or replication errors. Because of the relative reproductive success of organisms with particular qualities, natural selection gradually increases or decreases the frequency of certain traits in a population's genetic variation over successive generations.
The Earth is estimated to be around 4.5 billion years old, and at least 3.5 billion years ago, the earliest undisputed evidence of life on Earth has been discovered. In contrast to abiogenesis, which explains the origin of life, evolution explains how early lifeforms developed into today's complex ecosystems. A last universal common ancestor (LUCA) from which all known species have diverged has been hypothesized to be the source of all life on Earth, based on the similarities between all living things.
Genetic material inherited from one's parents is passed down to one's descendants in DNA. As a result of mutations or the re-arrangement of genes during sexual reproduction, kids can have different genetic characteristics. Minor, haphazard differences separate the progeny from their parents, and it is more likely that the children will survive and reproduce if those differences are beneficial. Therefore, fewer people will have the same likelihood of reproducing in the future since their progeny will have more beneficial variation. As a result, features that help animals adapt to their environment become more prevalent in descendent populations. The population changes due to these variations, which gives rise to the world's wide variety of living organisms.
Charles Darwin's "On the Origin of Species", first published in 1859, ushered in a new era in evolutionary theory. In addition, the work of Gregor Mendel on plants aided in the explanation of hereditary genetic patterns. Research in paleontology, the study of populations, and an international scientific network have all contributed to a better understanding of evolution. Speciation has been empirically observed in the lab, and the wild, and scientists now have a decent grasp on how new species emerge (speciation). Biological biologists employ evolution as a primary scientific theory to comprehend life. It is used in many fields, from medicine to psychology, conservation biology, anthropology, and forensics.
According to evolution, the most important concepts can be summarized with some key points below:
Assembling natural history collections and arranging them in museums was popular in the 19th century. Naturalists were engaged by the European expansion and naval expeditions, while the curators of significant museums displayed preserved and live specimens of the variety of life in their collections. He was an English graduate who had been schooled and trained in the fields of natural history. These naturalists would study the vast collections of specimens held and controlled by museum curators. Darwin worked as a ship's naturalist on the HMS Beagle during a five-year study voyage around the globe. During his voyage, he examined and gathered a wide variety of species from the shores of South America and the Galápagos Islands, which he found fascinating.
According to Darwin, Orchids have evolved various pollination strategies developed from their essential floral elements. Darwin gathered and studied the natural history of organisms worldwide throughout his travels. According to his research, each species evolved from an ancestral line with many characteristics. Natural selection, which he coined in 1838, was the mechanism he proposed to explain this phenomenon. How much and how many resources are available to support a population determines the size of that population. There must be a balance between the growth of the population and the resources available for the population to remain stable year after year. For every generation, there are fewer and fewer individuals who are able to make it out to the other side. Resources that are necessary for survival must be contested. As a result, Darwin realized survival was not a matter of chance alone. An organism's likelihood of surviving and reproducing are influenced by the unique characteristics, or "traits," that each individual within that species possesses. It is more likely that well-adapted individuals will have more children than those who are less well-adapted. Over time, traits detrimental to one's survival and reproduction would fade away. Over time, traits that aid an organism's survival and reproduction would accumulate. Using the phrase natural selection, Darwin explained how the unequal capacity of individuals to live and reproduce might lead to progressive population changes.
The hypothesis of natural selection is based on observations of variation in animals and plants. If you look at the close interaction between orchids and insects that Darwin discovered, you'll see how important it is for the pollination of plants. Several features attract insects, allowing pollen from the flowers to adhere to their bodies. Insects carry pollen from a male orchid to a female orchid in this manner. Even though orchids appear to be highly decorated, these specialized portions are formed of the same essential components as other flowers. It is widely accepted that Darwin's theory that orchid blossoms evolved from pre-existing pieces through natural selection may be found in his book, Fertilization of Orchids (1862).
When Darwin got a letter from Alfred Russel Wallace outlining a theory very similar to his own on natural selection, he was still deep in the trenches of experimentation. As a result, both theories were immediately published in conjunction. According to Wallace and Darwin, every tree branch represents a common ancestor in the evolution of life. Modern species were symbolized by the tips of the limbs, whereas the branches depicted common forebears shared by many distinct species. According to Darwin, all living organisms are connected, meaning that all life must have descended from a few forms or even from a common ancestor. "Descent with modification" is what he dubbed this process.
On the Origin of Species was published by Darwin in 1859, laying out his hypothesis of evolution through natural selection. According to his thesis, all life, including humanity, results from ongoing natural processes. Some religious organizations are offended by the notion that all life on Earth has a common ancestry. More than 99 percent of scientists currently embrace the hypothesis, which means their concerns are out of step with the scientific consensus.
Surviving to the strongest may be usually associated with Darwinian natural selection, but Herbert Spencer's Principles of Biology, published in 1864, is where this statement first appeared. According to Darwin, survival of the fittest misrepresents natural selection because it is not only about survival, and it's not always the fittest that survives in natural selection.
Darwin's studies and observations created the framework for current evolutionary theory, showing that creatures in groups differed, that some of these differences were inherited and that these differences could be influenced by natural selection. However, he was unable to explain these discrepancies. According to Darwin, traits that can be passed down from generation to generation result from an organism's use and depletion of those traits. There were plenty of examples he could draw from, such as huge ground feeders like ostriches, whose legs got stronger with exercise but whose wings got weaker with inactivity. Jean-Baptiste Lamarck proposed the notion of transmutation of species in 1809, and this misconception was referred to as the inheritance of acquired characteristics. Lamarckism, a term coined in the late 1800s, was the name given to this hypothesis. When Darwin attempted to explain how hereditary traits may be acquired, he coined the term "pangenesis." The tests of August Weismann in the late 1880s showed that changes in use and disuse could not be inherited, and Lamarckism began to lose popularity.
Gregor Mendel's groundbreaking work in genetics filled in the gaps left by previous scientists' explanations for how new traits could be passed down through generations. Research on pea plants by Mendel showed that hereditary traits are passed down by separating and rearranging genetic information during the creation of sperm and egg cells, then recombining that information during fertilization. An organism is given half its DNA from one parent and a half from the other in a random combination. Genes were initially referred to as information factors by Mendel. Genes are the fundamental elements of inheritance in living beings. Species' physical and behavioral development is governed by the information contained in these molecules.
DNA is the building block of genes. Nucleotides are the building blocks of DNA, a long molecule made up of individual molecules. In the same way, as the sequence of characters on a page encodes information, the sequence of nucleotides in DNA encodes genetic information. The DNA alphabet's "letters" form tiny instructions called genes. An organism's "instruction manual" is provided by the whole set of these genes when seen as a whole. However, mutations can alter the instructions in this DNA alphabet, affecting the instructions contained within genes. Chromosomes, which are DNA-carrying packets in cells, carry genes. In the offspring, the chromosomes are rearranged to produce new genetic combinations. Sexual reproduction can increase genetic diversity in populations even when no new mutations occur because genes interact during development to create unique combinations. People from different species interbreeding with each other can also expand the genetic diversity of a particular group of people, resulting in gene flow between populations. Genes that weren't previously present in a population can be introduced through this method.
The process of evolution is not a chance event. DNA mutations may be random, but natural selection does not rely on randomness: the environment controls the likelihood of successful reproduction. Evolution is inevitable if self-replicating, imperfectly copied organisms continue to reproduce over billions of years. Evolution does not produce a wholly formed organism in its current form. Instead, small changes accumulate over time. Ultimately, natural selection results in organisms better suited to their present habitats than their predecessors. In natural selection, no progress is made toward a goal. No matter how evolved, intelligent, or smart a living form may be, it is not the goal of evolution. Although snakes and lizards no longer need legs, they are descended from an ancestral scorpionfly with wings. For example, the flea (wingless parasite) descended from an ancestral scorpionfly with wings, and the snake (a lizard that no longer needs limbs) both evolved over time. In the end, organisms are nothing more than the result of a series of random mutations that either succeed or fail, depending on their current environment.
Extinction is frequently the result of abrupt alterations in the environment. One hundred and ninety-nine percent of Earth's species have vanished. Mass extinctions have occurred five times since the beginning of life on Earth, resulting in significant and rapid decreases in the number of species. Cretaceous–Paleogene extinction was the most recent, taking place 66 million years ago.
Genetic drift is a significant factor in a species' allelic frequency variation. Different gene variants are known as alleles. Genetic drift can't introduce new alleles to a population. Still, it can remove an allele from the gene pool and limit a population's diversity. The random sampling of alleles is the cause of genetic drift. To have a genuinely random sample, no outside influences can be at play throughout the selection process. It's like sifting through a brown paper bag, looking for marbles of the same size and weight but in different colors. It is entirely up to chance whether a person lives long enough to reproduce and pass on a sample of their ancestor's ancestry to the next generation through the alleles they inherit. A population's allelic frequency is the ratio of the number of alleles that share the same form to the total number of alleles in the population. Smaller populations are more susceptible to genetic drift than larger populations.
No change in the frequency of alleles over time is predicted by the Hardy–Weinberg principle under idealized conditions, including the lack of selection forces. Hardy–Weinberg equilibrium refers to a population that meets these criteria. For example, Hardy and Weinberg demonstrated that dominant and recessive alleles do not inevitably increase or decrease in frequency, as had previously been supposed.
No mutations, immigration, or emigration are allowed to maintain Hardy-Weinberg equilibrium, as these actions can alter allelic frequencies. As the last point, mating must be completely random, with each man (or female for that matter, depending on the species) considered equally desirable. This ensures that the alleles are mixed in a truly random manner. No matter how often you shuffle a population in Hardy–Weinberg equilibrium, no new cards are added, and no old cards are removed. The cards represent alleles in a population's gene pool in the deck.
In reality, no population can be perfectly in equilibrium with the Hardy-Weinberg model. Over time, the population's finite size and the processes of natural selection drive the allelic frequencies to shift.
Due to external factors, the population of an organism is substantially reduced during a short period. There is no advantage to any gene combination in an actual population bottleneck; survival is determined solely by chance. A population's genetic variety can be reduced or eliminated by a bottleneck. After a bottleneck event, subsequent drift episodes might reduce the population's genetic diversity. When the population lacks diversity, it is more susceptible to other selective forces.
The Northern elephant seal is a prominent example of a population bottleneck. The northern elephant seal population was reduced to as few as 30 animals due to over-hunting during the nineteenth century. They've fully recovered, with a population of around 100,000 people and rising. However, the bottleneck's impacts can be seen. Because the population is so homogeneous, sickness and genetic diseases are more prone to strike the seals.
Small new populations are formed with varying allele frequencies from the parent population due to the founder effect. One population splits into a new one due to geographic isolation and the founder effect. New populations may have a different allelic frequency than the original population, and this will modify how frequently specific alleles appear in the populations. The ancestors of a new population will significantly impact its genetic makeup and, thus, its long-term viability.
When the Amish arrived in Pennsylvania in 1744, they had a founder effect. The recessive allele for Ellis–van Creveld syndrome was detected in two of the colony's founders in Pennsylvania. Because the Amish live in religious isolation, they interbreed. As a result of generations of this practice, the incidence of Ellis–van Creveld syndrome in the Amish community is significantly higher than that of the general population.
It is the contemporary evolutionary theory that populations of organisms have a great deal of genetic variation due to mutation and recombination during sexual reproduction. Genetic drift, gene flow between sub-populations, and natural selection all contribute to the evolution of an organism's allelic frequencies. This emphasis on natural selection emphasizes the importance of the gradual accumulation of tiny evolutionary changes over lengthy periods.
An amalgamation of several scientific domains has led to a more comprehensive knowledge of evolutionary theory. A new field of study known as population genetics was born in the 1920s due to Ronald Fisher, J.B.S. Haldane and Sewall Wright combined Darwin's natural selection theory with statistical models based on Mendelian inheritance. An attempt was attempted to combine population genetic studies, field naturalists' observations of species and subspecies distributions, and fossil record analyses into a coherent explanatory model in the 1930s and 1940s
To better comprehend evolution, scientists like Ernst Mayr and Theodosius Dobzhansky applied genetic principles to naturally occurring populations. Genetics and the Origin of Species by Dobzhansky helped connect genetics and field biology by presenting the mathematical framework of population geneticists in a form more useful to field biologists and by demonstrating that wild populations had much more genetic variability with geographically isolated subspecies and reservoirs of genetic diversity in recessive genes than models of the early population geneticists had allowed for. Genes and field research helped Mayr develop the biological species idea that defined a species as a group of interbreeding or possibly interbreeding populations reproductively isolated from all other populations.
A new species' development depends on reproductively isolated subspecies, which Dobzhansky and Mayr both emphasize. George Gaylord Simpson's statistical examination of the fossil record helped integrate paleontology with a branching and non-directional process of evolution predicted by the modern synthesis into the fossil record.
Naturalist Charles Darwin collected fossils, living specimens (and non-living) in South America during the second voyage of HMS Beagle. He discovered armor bits that resembled larger copies of the scales found on nearby present armadillos, according to Darwin. Anatomist Richard Owen showed him the fragments were from extinct glyptodons linked to the armadillos. This was one, amongst many, patterns of distribution that aided Darwin in his hypothesis of evolution. Fossils, homologous structures (traits that originated from shared ancestry, rather than independent origin), and molecular similarities between species' DNA are all examples of evidence supporting evolution.
Paleontology, the study of fossils, provides evidence that all living things are interconnected. Only through the preservation of fossils can we see the evolution of life as we know it today. Paleontologists can build a family tree for all of Earth's living forms by studying fossils, which disclose the anatomy of the organism and the links between contemporary and extinct species.
Georges Cuvier is credited with founding modern paleontology. Sedimentary rocks, according to Cuvier, have distinct fossil communities within each layer. Simpler living forms lived in the deeper levels, which he believed to be older. It was pointed out to him that many organisms from the past no longer exist today. To understand the fossil record, Cuvier made a significant contribution by establishing extinction as an actuality. Cuvier postulated catastrophism or "revolutions" to explain the extinction of enormous numbers of species, which he attributed to geological disasters throughout the Earth's history. When James Hutton and Charles Lyell suggested that the Earth's geological processes were steady and constant, they overthrew Cuvier's revolution idea. However, the fossil record shows that massive extinctions have occurred. Consequently, the overall concept of catastrophism has resurfaced as a viable possibility for explaining at least some of the fast changes in living forms that appear in the fossil record.
The number of fossils that have been found and recognized has exploded in recent years. As a record of evolution, these fossils are essential. Ancestral relationships between previous and current living forms can be traced back to transitional species seen in fossils. Archaeopteryx is a good example of a transitional fossil, as it has both the traits of a reptile and a bird (such as a long, bony tail and conical teeth) (such as feathers and a wishbone). According to evolutionary theory, the discovery suggests that current reptiles and birds share a common ancestry.
Morphology, or the study of how different components of an organism look compared to one another, has long been used to group closely related species. Comparing the structures of adult creatures from several species or the patterns of cell growth, division, and even migration during an organism's development can be a means of accomplishing this.
In taxonomy, we identify and classify all living organisms. Ancestry-based classification of organisms is made possible by using features such as morphology and genetics. For example, orangutans, chimpanzees, gorillas, and humans are all members of the Hominidae family, which is a taxonomic grouping. Because they have a common ancestor, these animals are grouped (called homology).
These structures are known as homologous structures because they are seen in different species that no longer perform the same activity yet share structural similarities. Mammal forelimbs exhibit this characteristic. There are notable similarities in the bone structure of the forelimbs of mammals such as humans, cats, whales, and bats. However, the forelimbs of each of these four species are used for a distinct purpose. The same bones are employed for both purposes when it comes to a bat's wings and a whale's flippers. If they are unrelated and built for a specific purpose, such a "design" doesn't make sense. According to evolutionary theory, all four animals share a common ancestor, and each has experienced evolution over many generations to achieve similar structures. The forelimbs that resulted from these structural alterations may now perform various functions.
Analogous anatomical comparisons can be misleading, as not all anatomical similarities mean that there is a tight relationship. Organisms that share comparable habitats will often develop similar physical traits, a process known as convergent evolution. Even though sharks and dolphins look alike, they are not closely related; sharks are a type of fish, whereas dolphins are marine mammals. Such resemblances are due to the same selective pressures experienced by both groups. Changes that help swimmers have been favored by both parties. As a result, even though they are not closely related, they have developed similar appearances over time (morphology).
Identifying a shared ancestral link between two or more species is possible based on anatomical analysis of embryonic features. The embryo's growth may obscure this similarity, and the structures may take on new roles. The presence of a tail and pharyngeal slits are a part of the classification of vertebrates, including humans. Both features can be seen in the developing embryo, although they may not be readily apparent in the adult form.
In the past, it was believed that embryos of various species re-enact their evolutionary history because of their morphological similarities during development. An amphibian and a reptilian stage were previously considered necessary for developing human embryos into mammals. In other words, such a re-enactment is unsupported by scientific evidence. However, the initial phases of development across large groupings of species are very similar. For example, in its earliest stages, all vertebrates look strikingly similar, yet they bear no resemblance to any ancestral species. From this basic structure, various features emerge as development continues. We know today that this idea (that ontology recapitulates phylogeny) is only a superficial similarity of developmental stages to evolutionary history.
Vestigial structures are a special subset of homology that comprises various shared components. By "vestigial," we mean body components with no functional use for the organism in which they are found. In earlier forms, these seemingly irrational features were vestiges of organs that were critical. They appear to be leg bones from their predecessors who were able to walk on land, as is the case with whales. We still have wisdom teeth, tail bone, hair on our bodies (including goose bumps), and the semilunar fold at the corner of our eyes, to name a few.
The geographical distribution of species is the subject of biogeography, a branch of biology. Darwin and Alfred Russel Wallace were persuaded by evidence from biogeography, particularly the biogeography of oceanic islands, that species evolved in a branching pattern of common descent. Although endemic species are unique to an island and cannot be found anywhere else, many endemic species on an island may be found on the nearby continent. As a result, islands are often home to various closely related species with diverse ecological niches or means of living in the natural world.
When a single ancestral species colonizes an island with a range of open ecological niches, it diversifies by evolving into multiple species adapted to occupy those available niches. A few well-known examples include Darwin's finches, a group of 13 endemic finch species on the Galápagos Islands, and Hawaiian honeycreepers, a group of birds that once numbered 60 species and all descended from a single finch-like ancestor that arrived on the Hawaiian Islands around 4 million years ago and serves a variety of ecological roles. As another illustration, there's the Silversword alliance, an endemic group of perennial plant species found only in the Hawaiian Islands. This alliance includes a wide range of plant types, from trees to shrubs to ground-hugging mats, and is capable of hybridizing with other species and tarweeds found on the west coast of North America.
Genomic information is encoded in DNA molecules in all living organisms (except for RNA viruses). This information is encoded in an organism's DNA by genes. In general, one's looks and behavior are influenced by one's genes. There will be striking similarities in the DNA sequences of closely related organisms. When two organisms are far apart in terms of evolutionary distance, they will have less in common than those with close distance. There is a big difference in DNA between cousins and brothers since cousins are genetically far from each other, but brothers are genetically close and share comparable DNA. Similarities in DNA are used to show similarities between individuals and animals similarly to determine relationships.
When chimpanzees, gorillas, and humans are compared, the DNA of humans and chimps is shown to be up to 96% similar. Genome-to-genome DNA comparisons show that human and chimpanzee species share more in common than gorillas. Measuring the similarities between molecules and utilizing this data to figure out how various kinds of creatures are related throughout evolution is the focus of the science of molecular systematics. As a result of these comparisons, biologists have been able to build a tree of life's evolution on Earth. They've even permitted scientists to uncover the relationships between species that are so distantly related that their appearances bear no resemblance to those of their distant cousins.
Domesticated plants and animals can be bred by artificial selection. People control which animals and plants reproduce and which of their progeny survive so that they can influence future generations' genetic makeup. The development of domestic animals has been dramatically influenced by artificial selection. People, for example, have bred dogs to develop a variety of breeds. The Great Dane and the Chihuahua differ in size because of selective breeding. They and all other dogs are descended from a small number of wolves domesticated by humans less than 15,000 years ago in what is now China.
Broad diversity of plants has arisen as a result of artificial selection. Recent genomic data reveals that maize (corn) was domesticated in central Mexico 10,000 years ago, and the wild form's edible component was small and difficult to obtain before domestication. Since its inception, the Maize Genetics Cooperation • Stock Center has collected and cataloged more than 10,000 varieties of maize, each resulting from the combination of natural selection and mutation.
In artificial selection, the new breed or variation that emerges is the one with random mutations appealing to humans. Still, in natural selection, the surviving species have random mutations that benefit them in their non-human habitat. In natural and artificial selection, random mutations are the primary source of variation, and the underlying genetic mechanisms are nearly identical. Darwin's arguments in favor of natural selection were based on his meticulous observation of the results of artificial selection in animals and plants. These observations on the many types of domestic pigeons resulting from artificial selection occupied a significant portion of Darwin's book On the Origin of Species. For millions of years, Darwin theorized that natural selection could develop the distinctions seen today in living things if humans could make significant changes in domestic animals over short periods of time.
Two or more species coevolve when they impact the evolution of one another. Coevolution shows that genetically determined traits in each species directly result from the interaction between the two organisms, but the life around them influences all organisms.
The interaction between the acacia plant, which the ant uses for food and shelter, and the Pseudomyrmex ant is a well-documented example of coevolution. Since the two are so closely intertwined, new structures and behaviors have arisen in both organisms. The ant protects the acacia from herbivores and removes seeds from competing plants from the forest floor. Ant-eating floral parts and enlarged thorns on the plant's response to the ants' predation. To say that ants and trees coevolve does not mean that these two organisms are acting in an altruistic manner. As a result, both ant and tree populations profited from minor genetic modifications. The benefit increased the likelihood of the trait being handed to future generations by a small margin. The connection we see today was formed through a series of mutations that occurred throughout time.
Evolution can lead to the creation of new species under the appropriate conditions and with enough time. For a long time, scientists could not come up with a definition of species that was both exact and comprehensive. According to Ernst Mayr, a species is a population or a set of populations whose individuals are capable of spontaneously breeding with one another to create viable, fruitful children. There are no viable, fruitful children between one species and members of another species. Asexually reproducing creatures like bacteria do not fit Mayr's concept, which is widely accepted among biologists.
The separation of a single ancestral population into two distinct species is known as speciation. Allopatric speciation is a common method of speciation. When a population splits up due to distance, allopatric speciation begins. Separate populations can be formed due to geological processes like mountain range formation, canyon formation, or sea-level rise flooding land bridges. For speciation to occur, the genetic exchange between the two groups must be entirely disrupted by a significant separation. As a result of their genetic segregation, the genetically distinct populations have evolved in distinct ways. Various mutations will accumulate in each group, and different selective pressures will be applied to each group. If populations are reunited, they may no longer be able to interbreed due to the accumulated genetic alterations.
Prezygotic and postzygotic barriers to interbreeding can inhibit mating or fertilization (barriers that occur after fertilization). They'll be classified as separate species if there's no more way for them to cross-pollinate. The diversity of life on Earth is the product of four billion years of evolution, with an estimated 1.75 million distinct species now existing.
Speciation usually takes place over extended periods of time, making direct observations by humans scarce. On the other hand, speciation has been witnessed in living animals, and fossil records of previous speciation occurrences attest to this. Five new species of cichlid fish have been discovered in Lake Nagubago; all descended from a single common ancestor isolated from the parent population less than 5,000 years ago. The morphology (physical appearance) and lack of natural interbreeding provided evidence for speciation in this case. It is impossible to interbreed these fish because of their unique mating rituals and various colorations, which were altered somewhat when they were introduced into the new species.
All of biology's subfields are connected by the idea of evolution, which scientists universally accept. Evolving biology has a strong scientific foundation. According to Theodore Dobzhansky, "nothing in biology makes sense until it is seen in the context of evolution." However, evolution is not a static hypothesis. The scientific community engages in a great deal of debate over how evolution works. For instance, the rate of evolution is still up for debate. In addition, there are differing views on whether the organism or the gene is the main unit of evolutionary change.
For Darwin and his colleagues, evolution was a slow and steady process that would occur over time. Many tiny changes accumulated over extended periods of time lead to major changes in species, according to evolutionary trees. Scientists James Hutton and Charles Lyell laid the groundwork for gradualism. Geological change, according to Hutton, is a gradual process rather than a one-time event, as is the case with catastrophism, which advocates the belief that rapid changes have reasons that can no longer be seen in action. For biological changes, a uniformitarian perspective was adopted. The fossil record often shows evidence of new species arising unexpectedly and remaining in their current form over lengthy periods, which would seem to contradict such a perspective. While evolution may seem sluggish to us, paleontologists Niles Eldredge and Stephen Jay Gould created a theory in the 1970s suggesting periods of rapid change (between 50,000 and 100,000 years) alternated with extended intervals of relative stability, which they published in their seminal work. Punctuated equilibrium explains the fossil record without undermining Darwin's theory.
An organism is a common unit of selection in evolution. Natural selection occurs when an individual's reproductive success is improved or lowered by an inherited trait, and the number of an individual's surviving offspring is used as a metric of this success. Many scientists and philosophers have argued against the organism view. Richard Dawkins argues that looking at evolution from the gene's perspective can provide a wealth of information and that natural selection affects both genes and organisms when acting as an evolutionary mechanism. He explains this in The Selfish Gene, published in 1976.
Individuals are temporary and unreliable. After being dealt, chromosomes are shuffled into nothingness like cards in a deck. The cards, on the other hand, are unaffected by the shuffle. The cards are a person's genetic code. By crossing across, the genes don't die. They only change partners and keep marching on. They'll keep marching, of course. That's their prerogative. They are the cloners, and we are the ones who keep them alive. We are discarded after we have served our purpose. Genes, on the other hand, are eternal residents of geological time. A hierarchical viewpoint on selection, for example, was advocated by Stephen Jay Gould in the 1980s. | https://infoengine.org/home/ResearchTopics/Biology/Introduction_Evolution |
Which of the following is an example of convergent evolution?
Two different species independently gain the ability to fly
Two species merge together to form a single species
A species regains a trait that an ancestor had previously lost
Two populations living in the same geographic region acquire enough differences to diverge into two separate species
Two different species independently gain the ability to fly
Convergent evolution is the phenomenon by which two separate species evolve a shared trait. A classic example of this is that both birds and bats have evolved wings, but do not share a common ancestor prior to the development of this trait. Birds and bats developed their wings separately through completely unique mechanisms.
A population diverging into two separate species while residing in the same area describes the phenomenon of sympatric speciation. A species regaining a trait is an example of evolutionary reversal.
Example Question #2 : Understanding Divergent And Convergent Evolution
An example of __________ is the speciation of Darwin's finches through the accumulation of many small, distinct traits.
parsimony
divergent evolution
convergent evolution
artificial selection
divergent evolution
Convergent evolution is the phenomenon by which two species independently evolve a similar trait. An excellent example is the evolution of flight/wings in birds and bats, which do not share a common ancestor. Parsimony is a principle that guides scientific explanation toward simple terms, rather than eleborate principles. By parsimonious thinking, the simplest explanation is also the most likely to be true. Artificial selection is a form of evolution in which organisms are selected and bred for beneficial traits that would not necessarily be selected for in nature. Dog breeding and the production of numerous types of produce and grains are subject to artificial selection by humans (this is different from genetic modification).
Divergent evolution describes the accumulation of distinct traits that can lead to speciation events. A large population consists of a single ancestor species. Over time, different groups of the population come to inhabit different niches and develop traits for specialized inhabitance of that niche. As these changes accumulate, the population slowly develops distinct groups. When these groups can no longer reproduce due to some sexual barrier, a speciation event has occurred. This process aligns with the theory of evolution for Darwin's finches. | https://www.varsitytutors.com/gre_subject_test_biology-help/understanding-divergent-and-convergent-evolution |
The Cerrado is the largest South American savanna and encompasses substantial species diversity and environmental variation. Nevertheless, little is known regarding the influence of the environment on population divergence of Cerrado species. Here, we searched for climatic drivers of genetic (nuclear microsatellites) and leaf trait divergence in Annona crassiflora, a widespread tree in the Cerrado. The sampling encompassed all phytogeographic provinces of the continuous area of the Cerrado and included 397 individuals belonging to 21 populations. Populations showed substantial genetic and leaf trait divergence across the species' range. Our data revealed three spatially defined genetic groups (eastern, western and southern) and two morphologically distinct groups (eastern and western only). The east-west split in both the morphological and genetic data closely mirrors previously described phylogeographic patterns of Cerrado species. Generalized linear mixed effects models and multiple regression analyses revealed several climatic factors associated with both genetic and leaf trait divergence among populations of A. crassiflora. Isolation by environment (IBE) was mainly due to temperature seasonality and precipitation of the warmest quarter. Populations that experienced lower precipitation summers and hotter winters had heavier leaves and lower specific leaf area. The southwestern area of the Cerrado had the highest genetic diversity of A. crassiflora, suggesting that this region may have been climatically stable. Overall, we demonstrate that a combination of current climate and past climatic changes have shaped the population divergence and spatial structure of A. crassiflora. However, the genetic structure of A. crassiflora reflects the biogeographic history of the species more strongly than leaf traits, which are more related to current climate. | https://portal.research.lu.se/portal/en/publications/climatic-drivers-of-leaf-traits-and-genetic-divergence-in-the-tree-annona-crassiflora(15f85659-6972-48e3-a30f-9880f129e7e7).html |
23.1 What Are Species?
We can recognize and identify many species by their appearance
-Linnaeus developed morphological species concept
-classification of species on the basis of their appearance
Species form over time
-speciation is process by which one species splits into two or more daughter species, which
evolve as distinct lineages
-process is gradual
-when the two populations at various stages become new species, it is impossible to decide
whether individual belongs species 1 or 2
-reproductive isolation is when individuals of a population mate with one another, but not
members of the other population
-constitute distinct group in which genes recombine
-become independent evolutionary unit, separate branches on the tree of life
-Mary’s definition of species, biological species concept is:
“Species are groups of actually or potentially interbreeding natural populations which are
reproductively isolated from other such groups.”
-actually means individuals live in the same area and interbreed with one another
-potentially means although individuals do not live in the same area (cannot interbreed), but they
would interbreed if they get together
-does not apply to organisms that reproduce asexually
-reproductive isolation is one element to identify species
www.notesolution.com
23.2 How Do New Species Arise?
-not all evolutionary changes result in new species
-lineage may change over time without giving rise to new species
-speciation takes place when one species splits into 2 or more daughter species
-in isolated gene pool, allele and genotype frequencies change due to action of evolutionary
mechanism
-if 2 populations are isolated from each other and there are sufficient differences in their genetic
structure accumulate in isolation, members of 2 populations cannot exchange genes when they
come together
-speciation requires gene flow in the population whose members formerly exchanged genes be
interrupted
Allopatric speciation requires almost complete genetic isolation
-allopatric speciation is when population is divided by a physical barrier
-also known as geographic speciation
-dominant mode of speciation in most groups of organism
-physical barrier includes water body, mountain, and dry land for aquatic organism
-is formed when continents drift, sea levels rise, glaciers advance and retreat, and climates
change
-population that are separated are often initially large
-evolve differences due to gene drift and change in environment
-allopatric speciation also happens when some members of population cross existing barrier and
found a new isolated population
-species differentiate that when immigrants arrive to their place, they do not survive because they
often do not breed with resident species or their offspring is less competitive than that of resident
species
-genetic distinctness and cohesiveness of finch species are maintained
-closest relative of a species on one island is often a species on a neighbouring island rather than
species on the same island
-physical barrier’s effectiveness at preventing gene flow depends on size and mobility of species
-gene flow can sometimes be interrupted even in the absence of physical barriers
Sympatric speciation occurs without physical barriers
-sympatric speciation is partition of a gene pool without physical isolation
-disruptive selection in which certain genotypes have high fitness on one or the other of 2
different resources
-2 species become partly reproductively isolated because the mate primarily with individual
raised on the same type of location in the environment
-one species become more adapted to a certain type of location that they would not mate with
individual of another location
-were born at different time of the year so they do not interact
-2 incipient species are partly reproductively isolated
www.notesolution.com
Document Summary
Charles darwin said sexual selection was the cause for evolution conspicuous trait in species. Traits are exaggerated in species in which individuals of one sex (usually male) compete to mate with opposite sex. Exaggerated trait evolves in competition among males for access to female/ attracting discriminating females. Sexual selection can also increase rate of new species form. Comparison of the number of species found in sister clades (same ancestor) suggests development of new species from sexual selection. In promiscuous mating system, male bird evolved bright plumage and ornament (long tail feathers), female raises its child with no help from male. In monogamous species, members form pair bond and share responsibilities of raising the young. Individuals of both sexes have dull plumage and look alike. Sexual selection stimulates divergence of a lineage into many species. We can recognize and identify many species by their appearance. Classification of species on the basis of their appearance. | https://oneclass.com/textbook-notes/ca/utsc/bio/bioa-02h3/6489-chapter-23.en.html |
The gentoo penguin was formerly a single species, Pygoscelis papua, with a circum-Antarctic distribution. Previously, a few subspecies were named on the basis of slight morphological differences between populations inhabiting different places (they live not only on the Antarctic peninsula, but also on the South Shetland and Falkland Islands, South Georgia, and other places). They’re philopatric (breeding in the same place year to year), so the geographically isolated populations would be expected to be differentiated from one another due to natural selection and genetic drift operating on populations that don’t exchange genes with others.
A new paper in Ecology and Evolution (click on screenshot below, pdf here, and reference at bottom), suggests that this differentiation has proceeded to the point that there are now not just one gentoo species, but four. This is a subjective decision based on both size differences and genetic divergence, but more on that shortly. (The BBC also has a popular account of the research.)
Here are two pictures I took of Gentoos on the Antarctic Peninsula in the fall of 2019. They are notable for their white head stripe (said to look like a turban, which may be a source of their name), and their reddish-orange bills.
A colony, most of them prone against the icy wind:
And here’s the distribution from the paper above; penguin DNA and skins were sampled from the four general areas with the colored triangles (six locations total).
First, though, you need a criterion for delimiting different species before you start making decisions about species numbers. The classic criterion is known as the Biological Species Concept (BSC), which says that if two populations maintain reproductive isolation from one another (very limited or no gene exchange) where they coexist in nature, those populations can be considered separate species. The reproductive barriers must be based on genetic differences between the populations, and can involve many different impediments to gene exchange, including unwillingness to mate, sterility or inviability of hybrids, breeding at different times of year, preferring different microenvironments within the same general area, and so on.
The BSC is obviously be best applied where populations are sympatric—that is, that live in the same place so we can actually determine whether the barriers to gene exchange are effective. But it can still work if populations live in different places BUT, when you forcibly mate them in the lab or in zoos, the hybrids are sterile or inviable. Those hybrid problems would certainly occur in nature, too, so it’s a valid inference that hybrid problems of this sort found for allopatric populations (living in different areas) mean that those populations are different biological species.
However, the converse isn’t true: if populations can produce fertile and viable hybrids in captivity, that doesn’t mean they are the same species, for they could produce some fertile and viable hybrids in zoos but not mate with each other in the wild because of different breeding periods or sexual distaste. (This is true of lions and tigers, which can occasionally produce fertile hybrids in zoos but have never been found to hybridize where they co-occur in nature.)
Thus, using the BSC on allopatric populations is a subjective matter unless their hybrids are sterile or inviable. And this uncertainty holds for gentoo penguins. The populations samples in this study come from geographically isolated populations, and I don’t know anything about inter-population hybridization in zoos. One can’t, therefore, use the BSC on gentoos, a concept that I consider asthe best species concept for a number of reasons. (For a discussion on why I favor the BSC, see Chapter 1 and the Appendix of my book with Allen Orr, Speciation.)
The authors, then, default to another species concept when sampling the gentoos: the phylogenetic species concept (PSC). It’s defined as “the smallest diagnosable cluster of individual organisms within which there is a pattern of ancestry and descent.”
I discuss the PSC in the appendix of Speciation; it has several problems that make it less than optimal. “Diagnosable” means that the clusters can be told apart. But this doesn’t necessarily reflect genetic differences between populations. Suppose that one population of penguins lives on an island surrounded by ample marine food, while the other population has less food. The former population could produce large penguins, while the other population, with meager food, could comprise small penguins. You might be able to tell the adult penguins apart by size, making the two clusters “diagnosable”, but it wouldn’t be a meaningful difference, not reflecting anything about the genetic distinctness of the population. Such differences could occur in just a single generation due not to evolution but to effects of the environment on development.
Further, if populations are geographically isolated, as with those on different islands, then there will be a parental pattern of ancestry and descent for each island. Each individual will be born to parents from its own island, so that criterion is met. Couple that geographic isolation with “diagnosable” traits, even nongenetic ones, and you get a new species. But what does that mean? Very little, at least in terms of biology. As I’ve emphasized, “species” exist to describe the “lumpiness” of nature in one location: the fact that, say, birds in one forest don’t blend imperceptibly into one another, but fall into distinct groups. The groupings reflect lack of interbreeding in nature, and any sensible species concept has to deal with that lumpiness in one area. The origin of species is the same as the origin of distinct “lumps” of plants and animals that can be told apart in a single place.
So if you move a population of Asian humans to one island and Caucasian humans to another, and force them to stay there forever, the PSC automatically makes them different species of humans, for each individual can (by both looks and genes) be diagnosed, and the populations maintain a pattern of ancestry and descent. But humans are known to be a single one species with many different morphologies and statistical differences in gene frequencies from place to place. Asians aren’t one species and Caucasians another, as they readily interbreed where they coexist. So what does it meant to call the Asians on island X as a species different from the Caucasians on island Y? Nothing.
I went into this matter because, to some extent, this is the situation with the gentoo penguins. They live in different places, and while there are diagnosable genetic differences between them, just as there are for human populations if you use a combination of many genes, and while there are also morphological differences between the gentoo populations, those differences are purely in size and shape. In the end, if you think the DNA differences between the gentoo populations are sufficient to make them different species, that’s purely a matter of taste, for there is no obvious correlation between DNA differences and ability to produce fertile hybrids were the populations to co-occur in nature. And we don’t know whether the morphological differences between the gentoo populations are even based on genetic differences, as they could be developmental differences induced by the different environments that, as the authors admit, exist in the different populations of gentoos.
That said, here are the data.
For morphology, the authors looked at 39 penguin skins from five locations collected in two museums. Measurements were taken on nine linear characters involving beak and body size. Note that every character is related to body size. (See the paper for the list of traits).
For DNA, the authors used 69 DNA samples from five of the six populations described in the present study. They used more than 10,000 DNA sites for their analysis of genetic distance (separation), so it’s a very large sample. This sample and some of the analysis described in this paper comes from a 2018 paper in Molecular Ecology by Clucas et al.
The results can be stated briefly (I hope!)
Morphology. The penguins generally sorted out by location (four clusters) based on statistical combinations of the body-size traits (principal components analysis and linear discriminant analysis), but many of the individual penguins were NOT morphologically diagnosable by even combinations of their size measurements. You can see that from the overlap of the clusters in the two plots below (each color of a dot is one individual from a given population; triangles are population means). Here are the scatterplots for size traits:
The lack of diagnosability can be seen because the position of a dot does not tell you with 100% certainty its color; that is, you can’t diagnose an individual with absolute certainty even from statistical combinations of the nine body size traits. In general, populations are differentiated, but they don’t fall into completely separated clusters, which is required for “diagnosability”. The authors also note that, apart from size, there were no other obvious traits in plumage that could be used to tell the populations apart. So we have populations somewhat differentiated by body-size traits (and thus shape traits), but that’s also true for many species that are not “split” into multiple species, including H. sapiens.
DNA. The DNA was much better at diagnosing individuals. In fact, using the 10,000+ DNA sites, an individual could absolutely be assigned to population, which means there’s been pretty substantial genetic divergence between the four localities (Falkland Is., Kerguelen Islands, South Georgia Island, and South Shetlands/Antarctic Peninsula). The clustering based on DNA shows absolutely distinct clumps, and putting the DNA into a phylogeny (family tree), one sees that the four groups form a distinct pattern of ancestry.
The phylogeny of the four groups (the “100” means that the clusters are extremely strongly supported using “bootstrap” analysis:
How many species? Based on these data, the authors divide gentoos into four species in the genus Pygoscelis:
P. papua in the Falkland Islands
P. ellsworthi in the South Shetland Islands
P. taeniata in the Kerguelen Islands, and
P. poncentii from South Georgia Island.
The upshot:
The four populations have differentiated fairly strongly in their DNA, which means (since the DNA sites were “neutral” ones, reflecting the passage of time), these populations have been geographically isolated from each other for a long while, though I can’t say how long. The populations are diagnosable from DNA and apparently have a pattern of ancestry and descent, so they fit the concept of phylogenetic species. But if you use morphology by itself, these are not phylogenetic species, as they aren’t diagnosable from morphology. But all you need is one or a few traits to diagnose a population as a new species according to the PSC, so these are phylogenetic species. I would be wary of diagnosing them from morphology, anyway, since these are size traits and likely to be affected by local environments as well as genes.
But are these BIOLOGICAL species? The answer is that we don’t know. I suspect that, if a penguin from Kerguelen were to somehow find its way to the South Shetlands, it could mate with the locals and produce fertile hybrids, but that’s just my feeling. Because this doesn’t happen, and I don’t know about the situation in zoos, we can say only that we’re not sure whether these are biological species. One could make a somewhat informed judgment by seeing if other species of birds with similar genetic divergence would be unable to produce hybrids where they co-exist; that would give us some idea of whether this amount of genetic divergence between the penguin populations would prevent the formation of fertile hybrids. But of course each group of birds will have its own “speciation clock” (for one thing, the generation times differ), so that would also be a guess, though an informed guess.
Should the authors have named these as different species? My answer (assuming I adhere to the BSC) is, “I don’t know; it depends on what we can find out from their reproductive compatibility in captivity.” If they can’t produce fertile and viable hybrids in zoos, or simply refuse to mate with each other there, that gives us a pretty good idea that they’d be reproductively isolated were they to co-occur in nature; hence they could with some confidence be called different biological species. But PSC species don’t always coincide with biological species, so I reserve judgment and just say that the authors are “splitters”, looking for reasons to divide up populations into distinct species.
One reason biologists like to do this is because it’s easier to conserve animals that belong to different species than those that simply belong to different populations of a single species (subspecies are, under America’s Endangered Species Act, also conserved by law). Splitting thus enables you to try to save more animals, as is evident from the tweet below. Fortunately, gentoos aren’t endangered, though some of the sampled populations have decreased in size over the last two decades. And, if global warming hits Antarctica and the southern oceans hard, as it is likely to do, eventually all the penguins will go extinct, and splitting will have made no difference.
Note the implication in this tweet that the species were “identified,” as if there are pre-existing and real entities out there that have finally been pinned down. But of course that’s not true; these populations differentiated genetically slowly over time, and there’s no one instant where a new “species” has popped into being and can be identified as such.
Greater gliders yesterday, penguins today… all hail the splitters! This has a proper impact on conservation efforts, so it's great to see these species identified. https://t.co/kXLPUnEhLv
— Dr Nick Crumpton 🇪🇺 (@LSmonster) November 7, 2020
h/t: Paul
___________________
Morphometric and genetic evidence for four species of gentoo penguin. Ecol Evol. 2020; 00: 1– 11. https://doi.org/10.1002/ece3.6973, , , , . | https://whyevolutionistrue.com/2020/11/09/new-paper-claims-that-gentoo-penguins-are-now-four-species-not-one/ |
LPF has managed to save the Grey-breasted Parakeet from extinction, thanks to its upward population trend, we hope to continue improving the species’ conservation status.
Grey-breasted Parakeet
Genetic research to infer the pure captive population of P. griseipectus
The IUCN Endangered grey-breasted parakeet (Pyrrhura griseipectus) has a historical range of 15 localities in Brazil but is currently found in only three areas in the state of Ceará: the Serra do Baturité, Quixadá and Ibaretama. The forests of Serra do Baturité have been greatly reduced to accommodate coffee and in 1996 only 13% of the forest remained. However, data from the last 10 years indicate that both the size of observed groups and the area occupied by the species in the Baturité Mountains are slowly increasing, probably because of intensive conservation management and education campaigns.
The Grey-breasted Parakeet Project was created in 2007, with the support of Loro Parque Fundación (LPF), Chester Zoo and ZGAP (Zoological Society for the Conservation of Species and Populations), especially to save this bird from extinction. Preliminary results have shown that the cause of population decline of great-breasted parakeets was due to poaching and habitat loss (nesting sites). The first breeding success in nest boxes was achieved in April 2010, and since then, the number of occupied nest boxes has increased every year. In eleven years, more than fifteen hundred chicks emerged from the nest boxes, making it one of the most successful short-term nest box programs.
Since the number of individuals in P. griseipectus populations remains low in the wild, specimens from the captive breeding program may offer a great opportunity to take the necessary actions for the conservation of this species, including reintroduction initiatives. Any decision involving the management of individuals and reintroduction must be made with great care, aiming to preserve genetic diversity, and avoiding the introduction of less adapted alleles (each of the versions in which the same gene can manifest itself) and focusing on choosing individuals with greater chances of survival. The biggest obstacle to implement these actions today is the lack of knowledge about genetic composition of natural populations and genetic variability of individuals.
Therefore, Loro Parque Fundación supports a genetic study of the two known populations of P. griseipectus and a diagnosis of genetic divergence (process by which two or more populations of an ancestral species accumulate independent genetic changes over time, often leading to reproductive isolation) between this species and its related species P. leucotis. This divergence is very important for the conservation of P. griseipectus, as historically these two taxa have been treated as a single species. This taxonomic confusion is of concern because it may have caused the two species to be kept together in captivity, which could result in hybridization that would be detrimental to natural populations.
The project aims to obtain relevant information for decision-making related to individual selection for captive breeding programs. It focuses on developing tools to choose individuals with the lowest proportion of admixture in their genomes and to determine from which population they may come from. With this framework it would be possible to indicate which individuals should be recommended for breeding programs and where they should be reintroduced if that is the case. | https://www.loroparque-fundacion.org/en/portfolio/pyrrhura-griseipectus-grey-breasted-parakeet/ |
Is evolution adaptive? Not if there is no variation for natural selection to work with. Theory predicts that how fast a population can adapt to a new environment can be limited by the supply of new mutations coming into it. This supply, in turn, depends on two things: how often mutations occur and in how many individuals. If there are few mutations, or few individuals in whom they can originate, individuals will be mostly identical in their DNA, and natural selection will be impotent.
This theoretical prediction has been hard to test. The rate at which new mutations arise in a population can be manipulated experimentally, and some work has shown that the fitness of a population increases more rapidly if more new mutations appear per generation, lending support to the mutation-limitation hypothesis . However, the question remains whether this limitation has played a role in the history of life over the evolutionary timescale. Maybe all natural populations are so large, the mutation rate so high, and/or the environment changes so slowly, that any novel variant required for adaptation is already there when selection starts to act? Some recent work does suggest that when strong selection begins to favor a certain phenotype, multiple distinct genetic variants producing this phenotype spread; this is what has happened, for instance, at the origin of insecticide resistance in wild populations of Drosophila melanogaster or lactose persistence in humans . In many other cases, though, adaptations seem to originate through a single mutation event, suggesting that the time needed for this mutation to arise may be important.
To complicate things, adaptation is hard to quantify. It leaves a trace in differences between individuals of the same species as well as of different species. However, this trace is often masked or confounded by other processes, including natural selection disfavoring newly arising deleterious variants, interference from selection acting at linked sites, and changes in population size. In 1991, McDonald and Kreitman have come up with a method to infer the rate of adaptation in the presence of strong negative selection, and later work has developed upon it to control for some of the other confounders. Still, the method is data-intensive, and previous attempts to employ it to compare the rates of adaptation between species have yielded somewhat contradictory results.
The new paper by Rousselle et al. recommended by PCI Evol Biol fills this gap. The authors use published data as well as their own newly generated dataset to analyze, in a McDonald and Kreitman-like framework, both closely and distantly related species. Importantly, these comparisons cover species with very different polymorphism levels, spanning two orders of magnitude of difference levels.
So is adaptation in fact limited by supply of new mutations? The answer is, it depends. It does indeed seem that the species with a lower level of polymorphism adapt at a lower rate, consistent with the mutation-limitation hypothesis. However, this only is true for those groups of species in which the variability is low. Therefore, if a population is very small or the mutation rate very low, there may be in fact not enough mutations to secure its need to adapt.
In more polymorphic species, and in comparisons of distant species, the data hint instead at the opposite relationship: the rate of adaptations declines with variability. This is consistent with a different explanation: when a population is small, it needs to adapt more frequently, repairing the weakly deleterious mutations that can’t be prevented by selection under small population sizes.
There are quite a few problems small populations have to deal with. Some of them are ecological: e.g., small numbers make populations more vulnerable to stochastic fluctuations in size or sex ratio. Others, however, are genetic. Small populations are prone to inbreeding depression and have an increased rate of genetic drift, leading to spread of deleterious alleles. Indeed, selection against deleterious mutations is less efficient when populations are small, and less numerable species accumulate more of such mutations over the course of evolution . The work by Rouselle et al. suggests that small populations also face an additional burden: a reduced ability to adapt.
Has the rate of adaptation in our own species also been limited by our deficit of diversity? The data hints at this. Homo sapiens, as well as the two other studied extinct representatives of the genus Homo, Neanderthals and Denisovans, belong to the domain of relatively low polymorphism levels, where an increase in polymorphism matters for the rate at which adaptive substitutions accumulate. Perhaps, if our ancestors were more numerous or more mutable, they would have been able to get themselves out of trouble, and there would be multiple human species still alive rather than just one. | https://evolbiol.peercommunityin.org/public/user_public_page?userId=873 |
Four forces influence the process of evolution. These forces include natural selection, gene flow, mutation, and genetic drift. Each of these forces has an impact on variation within and between populations. Natural selection refers to the process by which best-suited individuals reproduce offsprings that guarantee their survival and existence. Parents pass on genes to offspring that give them a survival advantage over other individuals. Natural selection causes variation by propagating the inheritance of traits through successive generations. Natural selection has four main components that include variation, inheritance, population growth, and differential reproduction and survival of individuals. The variation takes place when a trait is inherited and passed on over different generations. Inherited traits are responsible for the survival of individuals because they give them an advantage over others. This way they reproduce and pass on good traits to their progenies and enhance survival. In this case, survival depends on the reproductive success of individuals. Gene flow refers to the carrying on of genes from one population to the other. Gene flow causes genetic variation if transported genes land in a population in which they did not exist before. This is because new genes are incorporated into a population that did not possess them. It mostly depends on the type of organisms that are involved in the exchange of genes. An example is a pollination in which pollen moves from one plant to another. Within a population, it can increase variation by introducing or reintroducing genes. Between populations, it can reduce the possibility of speciation because it makes different populations genetically similar. This encourages the propagation of that species by reproduction.
Mutation refers to the random alteration of the genetic composition of an organism. Mutations are random and bring variation to different aspects of an organism’s life. Evolution is because of the accumulation of mutations. Within and between populations, a beneficial mutation increases the reproductive ability of organisms. They also bring genetic variation by altering the genome of the organism’s DNA and this increases the chances of the mutation being carried over successive generations. Harmful mutations lower the chances of an organism’s survival. They render the progeny less able to adapt and survive when inherited from parents. Genetic drift refers to a change in the frequency with which a gene occurs in a population. This results from the fact that genes present in an offspring represent a random sample of the parent’s genes. Within populations, genetic drift decreases genetic variation due to a phenomenon known as a bottleneck. This happens when the size of a population decreases and so a certain gene may disappear from a population completely. Between populations, variation increases because the population is large and the chances of genes surviving are high.
An isolating mechanism is a factor that prevents different species from reproducing. They include genetic variations, behavioral, geographical, and morphological differences. These barriers lead to reproductive isolation that ensures that species remain different. Isolating mechanisms play an important role in the process of speciation. Speciation is a process through which new species come into existence. It arises from the prevention of gene flow between populations. Isolation mechanisms prevent the flow of genes between populations by creating productive barriers that lead to the emergence of new species. If different populations reproduce, then they belong to the same species. As such, their reproduction can never give rise to a new species. | https://nerdytom.com/how-forces-of-evolution-influence-variation/ |
Search Terms:
AND
OR
Search Definitions:
Contains this
Begins with this
Total searching time: 4.00sec
Searching Category
User input query
DEFINITION search string
evolution
Number of Results
40
16S rRNA
Author:
Mirrored from
Tsute Chen's Glossary of Microbiology
Definition:
A large
polynucleotide
(about 1500 bases) which functions as a part of the small subunit of the
ribosome
of
prokaryotes
and from whose sequence
evolutionary
information can be obtained; the
eukaryotic
counterpart is 18S rRNA.
Darwin, Charles
Definition:
An English naturalist who lived from 1809 to 1882; he studied and documented the flora and fauna of parts of coastal South America, including the Galapagos Islands, but is most famous for developing the theories of
evolution
and
natural selection
.
Haldane's evolutionary unit
Definition:
A unit of measurement, given in darwins, which measures the increase in body size of a
chronospecies
over evolutionary time.
HeLa cells
Definition:
A line of
tissue culture
cells
which originated from some human cervical
cancer
cells and which was established in 1951 by Gey, Coffman, and Kubicek. The line is named after the woman who donated the
tumor
, Henrietta Lacks, and is the first tissue culture made from human
epithelial
-like cells. The line is used to study life processes and the cultivation of
viruses
. (It is also interesting to note that the woman who donated the cells has since died, but that the line from her tumor lives on in scientific laboratories. In some respects, the establishment of these cells in a line is not unlike instant
macroevolution
from human to
protozoan.
)
Jordan's rule
Definition:
An
evolutionary
rule that states that the closest genetic relatives of a given
species
are found very near it, but the two groups are isolated by some kind of natural barrier (such as a river) that neither species can cross easily.
adaptive radiation
Definition:
The
evolution
of new species or sub-species to fill unoccupied ecological niches.
allopatric speciation (geographic speciation)
Definition:
The
evolutionary
process through which two geographically separated (and therefore non-interbreeding)
populations
of the same
species
become less and less similar to each other over time (via
mutation
or the success of different traits in each environment) and eventually become distinctly different species.
allopatrically
Definition:
An adverb refering to a specific mechanism of evolutionary divergence. A species which arose allopatrically from another diverged from the other because of
evolutionary
changes occurring in two different geographically separated populations. Also see
allopatric
and
speciation
.
analogy (adj. analogous)
Definition:
Two anatomical structures or behavioral traits within different and unrelated organisms which perform the same functions in each organism but which did not originate from an ancestral structure or trait that the organisms' ancestors had in common. Instead, the structures or traits arose separately and then later evolved to perform the same function (or similar functions). See also
convergent evolution
. Compare
homology
.
anaplasia (anaplastia; adj. anaplastic)
Definition:
The loss of cellular organization and differentiation; typical of a tumor.
A phase in the
evolutionary
development of a species characterized by increase hardiness and diversification.
biogenetic law (recapitulation theory)
Definition:
The
theory
that "
ontogeny
recapitulates
phylogeny
," which means that one can trace the evolutionary development of a
species
by studying the development of an individual
embryo
or young of that species. The theory is still used, especially in
paleontology
, but has been found to not be strictly true when applied to problems in
biology
.
bioseries
Definition:
A series of recognizable
evolutionary
changes in a single inheritable characteristic.
catagenesis (katagenesis)
Definition:
Evolutionary
change toward simpler, more general forms, and away from complex forms which are highly-specialized for a particular set of environmental conditions.
chronospecies
Definition:
A chronospecies is a
species
which changes physically,
morphologically
,
genetically
, and/or behaviorally over time on an evolutionary scale (experiences a
phyletic shift
) such that the species from the early point in time and the species it becomes at the later point in time could not be classified as the same species had they existed at the same point in time. Throughout the change, there is only one species at any point in time and diversity does not increase.
classification
Author:
Mirrored from
Tsute Chen's Glossary of Microbiology
Definition:
The arrangement of organisms into groups based on mutual similarity or
evolutionary
relatedness.
conserved sequence
Definition:
A
base sequence
in a DNA molecule (or an
amino acid
sequence in a
protein
) that has remained essentially unchanged throughout
evolution
.
evolutionary computation (genetic algorithms, genetic programming)
Definition:
Evolutionary computation, genetic algorithms, and genetic programming are all computer disciplines involved with modeling genetic inheritance and/or biological evolution in computers.
For more information, visit
The Hitch-Hiker's Guide to Evolutionary Computation
.
evolutionary distance
Author:
Mirrored from
Tsute Chen's Glossary of Microbiology
Definition:
In
phylogenetic
trees, the sum of the physical distance on a tree separating organisms; this distance is inversely proportional to evolutionary relatedness.
fixation
Definition:
An attachment. Being affixed. Immobilization by being glued to something solid.
Evolutionarily
, a state where every single individual within a
population
is
homozygous
for a particular
allele
(and therefore the
phenotype
that the allele confers). For example, in a population where everyone has blue eyes, the allele for blue eye color is fixed and everyone will continue to have blue eyes in the future, as long as no new individuals come into the population from elsewhere.
Psychologically, an obsessive amount of attention toward something.
The conversion of an inorganic source of an element (like nitrogen or carbon) into an organically useful form.
genetic distance
Definition:
A way of measuring the amount of
evolutionary
divergence in two separated
populations
of a
species
by counting the number of
allelic
substitutions per
locus
that have cropped up in each population.
homoplasy (adj. homoplasic)
Definition:
Organs or other bodily structures within different
species
which resemble each other and have the same functions, but which did not have a common ancestral origin and development. Instead, the parts arose via
convergent evolution
and are thus
analogies.
hypertely
Definition:
An evolutionary term describing a state in which an organism's body size or body structure becomes overspecialized such that it becomes a disadvantage. For example, overly large body size, or color/marking imitations of another species such that camouflage is no longer possible. Also, many traits which arise from sex selection tend to be disadvantageous overall to the organism (in terms of survival) but advantageous when the organism wants to attract a mate.
index fossils
Definition:
Fossils (or groups of fossils) which are used by geologists and
paleontologists
to help correlate different events or processes in different parts of the world which happened at the same time.
Species
which make good index fossils are able to tolerate a wide range of ecological conditions, are geographically widespread, common, easy to find, and evolutionarily short-lived (that is, they speciated and then quickly became extinct). In general, they are also
planktonic
and very small.
inheritance of acquired characteristics (Lamarckism, Lamarckian inheritance)
Definition:
The obsolete
theory
that offspring can
inherit
physical or behavioral characteristics from a parent that the parent acquired during its life. For example, a giraffe which stretches its neck to reach leaves at the top of a tall tree and thus ends up with a slightly longer neck can pass on the long neck trait so that its offspring also have long necks and can stretch it even longer. The theory, now known to be incorrect, was popularized by Jean-Baptiste Lamarck (1744-1829) and played an important role in the history of the study of evolutionary biology.
k selection
Definition:
In
evolution
, the
selection*
of traits that aid an organism's competitive capability when the population is at or near its carrying capacity.
karyoevolution
Author:
Mirrored from
Jim Croft's Flora of Australia
Definition:
Evolutionary
change in the
chromosome set
, expressed as changes in number and gross structure of the chromosomes; (more broadly), evolutionary relationships between
taxa
as indicated by
karyotype
differences.
macroevolution (adj. macroevolutionary)
Definition:
Evolution
on a
species
level (
speciation
and
extinction
) and at higher
taxonomic
classifications (appearance and disappearance of
genuses
,
families
,
orders
, etc.).
microevolution (adj. microevolutionary)
Definition:
Evolution
on a molecular level (changes within
DNA
, i.e.
mutations
), an individual organism level (DNA
recombination
,
chromosomal
mutations, reproduction,
natural selection
, etc.), and a population level (
genetic drifts
,
phyletic shifts
,
founder effects
, etc.).
parapatric speciation
Definition:
The
evolutionary
process of a single population of a
species
splitting into two or more species, where the new species end up in areas that are right next to each other (but not overlapping) and which do not have any geographic barriers in between. Parapatric speciation is intermediate between
allopatric
and
sympatric
speciation.
phylogeny (phylogenesis, phylogenetic, phylogenic)
Definition:
The evolutionary history of a particular
taxonomic
group, usually a species.
polyphyletic
Author:
Mirrored from
Jim Croft's Flora of Australia
Definition:
Composed of members that originated, independently, from more than one evolutionary line. Compare
monophyletic
and
paraphyletic
.
quantum evolution
Definition:
An extremely rapid
evolutionary
change in a single genetic lineage, thought to result from a sudden and radical change in the species' environment.
quantum speciation (saltational speciation)
Definition:
The rapid
evolution
of a new species from a small population that is partially or totally isolated from the parent population; the rapid speciation occurs due to
genetic drift
and founder effect and usually involves a few
mutations
that have a big impact on the organisms' observable physical traits.
radiation
Definition:
In
evolution
, the process through which a group of species diverge from a single ancestral form.
General term referring to the emission of electromagnetic waves (e.g. heat, light. etc.) or particles (e.g. neutrons) from from a material.
sickle-cell trait
Definition:
This condition occurs in people who have one of two possible
genes
(i.e., they are
heterozygous
for the
allele
) that code for the defective
hemoglobin
responsible for
sickle-cell anemia
. The codition is diagnosed by exposing an individual's
red blood cells
to a low oxygen environment; if the trait is present, the cells will turn to a sickle shape. People with this trait may suffer milder symptoms of sickle-cell anemia, or may have no symptoms. Some scientists believe the trait actually provides an
evolutionary
advantage in tropical environments because the slightly altered shape of the blood cells causes a person to be more resistant to
malaria
.
species
Definition:
Groups of
populations
(which are groups of individuals living together that are separated from other such groups) which can potentially interbreed or are actually interbreeding, that can successfully produce viable, fertile offspring (without the help of human technology). [Ernst Mayr, 1969] The species is the most fundamental unit of
evolution
and is the most specific
taxonomic
level.
spontaneous mutation
Definition:
A
mutation
which occurs by itself without first being affected by a
mutagen
, for example during the process of
DNA
replication
. Spontaneous mutations arise at a remarkably constant rate. The rate that spontaneous mutations arise has been used as an evolutionary clock to estimate how closely related two (or more) separate
species
are to each other.
sympatric speciation
Definition:
The
evolutionary
process of a single population of a species splitting into two populations which gradually evolve into two different species (as a result of genetic
mutation
and
variation
) while both diverging populations still occupy the same geographic area.
uniform rate hypothesis
Definition:
This states that any two
evolving
organismal lineages diverge from a common ancestor at a constant rate with respect to each other.
zoogenesis
Definition:
The origin of animal life on the planet.
The origin and
evolution
of a particular animal species. | http://life.nthu.edu.tw/~g864204/dict-search3.htm |
Why Is Genetic Variability Important – Evolutionary processes pt. 5, Meiosis and genetic diversity, Ppt, Quantifying the relationship between genetic diversity and population size suggests natural selection cannot explain lewontin’s paradox, Exploring the genetic variability and diversity of pearl millet core collection germplasm for grain nutritional traits improvement, Predicting geographic location from genetic variation with deep neural networks
A hereditary unit that can inherit the characteristics of the parents of generations. It represents the nucleotide sequence in DNA strands packed with chromosomes. These genes are responsible for the appearance of different traits, because these genes control the differences and similarities between different organisms. There are different genes that respond to population changes. For example, the human population consists of people with different physical characteristics that reflect genetic diversity. Genetic diversity between species can also be seen among species. For example, a population of dogs may consist of different dogs.
Genetic diversity (biological definition): the sum of different alleles in a species or population. Genetic diversity refers to many different species as well as one species.
Why Is Genetic Variability Important
Define terms related to a broader understanding of genetic diversity. Genetic variation is defined as the ability of a population to produce organisms with different genotypes.
Genetic Diversity Definition And Examples
Genetic variation is defined as the presence of different alleles with different frequencies of distribution among a particular population. Genetic variation refers only to changes in genomes at individual levels (i.e., between individuals) or at the species level (i.e., between species populations). The change may be due to a mutation; can cause mutations
Genetic diversity is a key factor contributing to biodiversity in the ecosystem. The term biodiversity refers to the biological diversity of life in it, and therefore includes many different microorganisms, plants and animals, including genes and their respective conditions or habitats.
Many researchers define genetic diversity as the amount and degree of genetic variation in a population, while biodiversity refers to the diversity of all organisms in an ecosystem at a given time.
Defined as the presence of different species in a particular region. All differences between species are due to gene diversity. Diversity is a key aspect of a healthy ecosystem. The extent to which this diversity is related to genetic diversity. The frequency of species extinction is lower with greater diversity. The greater the genetic diversity of a species, the greater the chances of survival of that species. In contrast, the less genetic diversity within a species, the less likely it is to survive. This is due to the fact that unhealthy behaviors, such as hereditary diseases, can be widespread. When put into breeding, there is a great tendency for offspring to show a deficiency due to the high probability of inheriting genes due to low diversity.
Genetic Diversity: The Hidden Secret Of Life
The only other source of diversity or population diversity besides genetic diversity is the environment. The influence of the environment and genes is responsible for the degree of diversity among individuals in a population.
The population can be small or large. Some of these people can mate and produce offspring. The rate of genetic change in humans is changing. Genetic diversity is present in the population because there are different genes of individuals due to small differences in DNA sequence. Mutations in the DNA sequence due to mutations can create different alleles. Allelic changes affect the body’s adaptation, physiological development, and ability to survive and reproduce in a variety of environmental conditions.
Genetic diversity is important because it can ensure that certain groups, species or populations can adapt to certain environmental factors. In addition to coping with environmental conditions, genetic diversity provides the ability to resist emerging diseases and epidemics. In contrast, low genetic diversity can increase a species’s susceptibility to biotic and abiotic stresses such as disease and drought, and therefore may increase the risk of extinction in the long run.
As mentioned in the article, genetic variation is caused by genetic variation. Genetic variations are especially important for species because it allows them to adapt to different environmental conditions. As a result, species are less likely to become extinct and therefore can live longer. Thus, genetic variation facilitates adaptation, survival, and species adaptation.
Ch. 16 Genes And Variation
The diversity of gene funds allows species to survive, because the more diverse the genes in the population, the more alleles there will be. Among these alleles may be some that allow some people to adapt better and thus get rid of certain stresses from the environment. In this way, the next generation will have an advantage because it can inherit such alleles that will be able to withstand certain conditions. This can help keep their species alive.
The ability of species to adapt to changes in the environment determines their longevity. This longevity depends on the genetic diversity of the species. For example, different people have different tolerances for stress among the same population. Some people who carry certain genes can live on most of the pollutants around them, while others cannot. Survivors can pass on to their offspring the genes responsible for resistance to pollutants, which will contribute to the adaptation of the population to future environmental conditions.
The greater the diversity of species, the greater the diversity of habitats. Species diversity preserves the functions and structure of ecosystems. Ecosystem diversity allows ecosystems to avoid the consequences of natural disasters or sudden changes. Low diversity ecosystems do not facilitate normal operation. Instead, a function that changes the composition of a species and causes a loss of natural resources can change permanently.
Genetic diversity provides information about the evolutionary process. The key to raw materials and evolution is considered, as well as the adaptation of species to world change. Some species cannot survive if they do not grow up and eventually adapt to changes in the environment.
Genetic Variation As A Cause Of Evolution
The genetic diversity of a small population is important because they can easily lose their genetic diversity over time due to the effects of genetic displacement. The formation and movement of one allele can lead to the disappearance of another, the loss of genetic diversity over time. When two people mate with a small population, the same allele is likely to be passed down from generation to generation, leading to a reduction in genetic diversity among this population. In contrast, many populations maintain genetic diversity by preserving their genetic material. Therefore, when a population is exposed to barriers, it loses more genetic diversity than most populations. Therefore, genetic diversity among large mammals is more important than that of small children because they produce fewer offspring. Conservation genetics is an important issue for conserving genetic diversity among endangered species.
If there is a large genetic diversity among the population, the extinction of a particular species is low because a low level of genetic diversity reduces the health of the population. This decline is one of the factors that increases the risk of extinction.
As a result, genetic diversity is responsible for changes in morphological, physiological, and behavioral patterns among populations and individuals, which in turn affect ecosystem services and ecological functions. Therefore, the reduction of genetic diversity among species populations could have an impact on both ecosystem services and human well-being.
Let’s explore the genetic diversity of sexual or sexually reproductive organisms. It is very likely that asexual reproductive organisms have genetic diversity. This is because in this case they will be limited to a genetic fund that will be based only on the parent. For example, cloned offspring of the mother are required in parthenogenesis. Through the clone, this means that the offspring will carry the same genes as the mother. This is because the mother can produce offspring in the absence of a male spouse. Therefore, as the gene pool is limited to the genome of the parent gene base, clones are expected to have any susceptibility to disease or genetic defects. In contrast, the genetic diversity of sexually transmitted species is greater. Sexual reproduction ensures the diversity of genes, because this process involves the genome of not only the mother but also the father.
Sources Of Genetic Variation (video)
Genetic diversity is important to humans. In fact, different colors of human eyes, hair color, skin color, height and so on. bar. The diversity of the human population is key to determining methods such as the use of fingerprints. The genetic diversity of human beings is significantly higher among the remote population, where the diversity among the population is less than the diversity of the total population change.
There are four factors that influence evolution in genetic diversity: mutation, genetic flux, gene flow, and natural selection. However, only mutations can produce completely new alleles. | http://www.hazelldean.com/2044/why-is-genetic-variability-important/ |
Genetic drift can result in the loss of rare alleles, and can decrease the size of the gene pool. Genetic drift can also cause a new population to be genetically distinct from its original population, which has led to the hypothesis that genetic drift plays a role in the evolution of new species.
What is genetic drift in evolution?
Genetic drift is a mechanism of evolution. It refers to random fluctuations in the frequencies of alleles from generation to generation due to chance events. Genetic drift can cause traits to be dominant or disappear from a population. The effects of genetic drift are most pronounced in small populations.
How do gene flow and genetic drift play a role in evolution? Genetic drift thus removes genetic variation within demes but leads to differentiation among demes, completely through random changes in allele frequencies. … In contrast, restricted gene flow promotes population divergence via selection and drift, which, if persistent, can lead to speciation.
Does genetic drift always cause evolution?
Genetic drift affects the genetic makeup of the population but, unlike natural selection, through an entirely random process. So although genetic drift is a mechanism of evolution, it doesn’t work to produce adaptations.
What is the role of genetic drift in speciation?
A second process called genetic drift describes random fluctuations in allele frequencies in populations, which can eventually cause a population of organisms to be genetically distinct from its original population and result in the formation of a new species.
What is genetic drift examples?
Example of genetic drift: a population of rabbits with alleles B and b, both alleles are present in equal frequencies p = 0.5 and q = 0.5 if 10 parents reproduce the probability of having an offspring with alleles B or b is 0.5; however, by chance, a slight difference in the offspring allele frequency might occur due …
What are the two types of genetic drift?
There are two major types of genetic drift: population bottlenecks and the founder effect.
What are the 5 factors of evolution?
There are five key mechanisms that cause a population, a group of interacting organisms of a single species, to exhibit a change in allele frequency from one generation to the next. These are evolution by: mutation, genetic drift, gene flow, non-random mating, and natural selection (previously discussed here).
Is genetic drift random?
Genetic drift describes random fluctuations in the numbers of gene variants in a population. Genetic drift takes place when the occurrence of variant forms of a gene, called alleles, increases and decreases by chance over time. These variations in the presence of alleles are measured as changes in allele frequencies.
What is gene flow and genetic drift?
“Gene flow is defined as a change in the genetic frequency by migration while genetic drift defined as a change of allelic frequency by random even or sampling error.”
What are two common causes of genetic drift?
Genetic drift can be caused by a number of chance phenomena, such as differential number of offspring left by different members of a population so that certain genes increase or decrease in number over generations independent of selection, sudden immigration or emigration of individuals in a population changing gene …
How is genetic drift measured?
We can calculate how much genetic drift we expect to find in a population if we know the effective population size. The expected variance in the frequency of an allele (call this frequency p) subject to genetic drift is: Var (p) = after one generation of genetic drift for diploid organisms.
Is genetic drift good or bad?
Every population experiences genetic drift, but small populations feel its effects more strongly. Genetic drift does not take into account an allele’s adaptive value to a population, and it may result in loss of a beneficial allele or fixation (rise to 100% frequency) of a harmful allele in a population.
How can genetic drift be reduced?
Inbreeding, or sibling mating, is a powerful method to reduce heterozygosity at every genetic locus in the mouse genome, allowing for uniformity in phenotype and forming the basis for experimental reproducibility.
How does population size affect genetic drift?
Small populations tend to lose genetic diversity more quickly than large populations due to stochastic sampling error (i.e., genetic drift). This is because some versions of a gene can be lost due to random chance, and this is more likely to occur when populations are small.
Why does genetic drift increase as population decreases?
Drift is more pronounced in such populations, because smaller populations have less variation and, therefore, a lower ability to respond favorably — that is, adapt — to changing conditions. | https://eyebuzzgallery.com/what-is-the-role-of-genetic-drift-in-evolution/ |
Research area : Population genetics; Speciation, Adaptation; From genes to phenotypes I am interested in the adaptation of natural populations to variations in their environment, and to the genetic basis of reproductive isolation. My research is based on population genomic approaches to understand how the different evolutionary forces shape genetic variation in nature. My main species of interest are marine fishes.
Additional affiliations
October 2013 - present
CNRS
Position
- Researcher
Publications
Publications (67)
Estimating the rate of exchange of individuals among populations is a central concern to evolutionary ecology and its applications to conservation and management. For instance, the efficiency of protected areas in sustaining locally endangered populations and ecosystems depends on reserve network connectivity. The population genetics theory offers...
During speciation-with-gene-flow, effective migration varies across the genome as a function of several factors, including proximity of selected loci, recombination rate, strength of selection, and number of selected loci. Genome scans may provide better empirical understanding of the genome-wide patterns of genetic differentiation, especially if t...
The European sea bass (Dicentrarchus labrax) is a temperate zone euryhaline teleost of prime importance for aquaculture and fisheries. This species is subdivided into two naturally hybridizing lineages, one inhabiting the north-eastern Atlantic Ocean and the other the Mediterranean and Black seas. Here, we provide a high-quality chromosome-scale as...
Our understanding of the genetic basis of local adaptation has recently benefited from the increased power to identify functional variants associated with environmental variables at the genome scale. However, it often remains challenging to determine whether locally adaptive alleles are actively maintained at intermediate frequencies by spatially v...
During the early stages of speciation, interspecific gene flow may be impeded by deleterious epistatic interactions in hybrids, which maintain parental allelic combinations at the speciation genes. The resulting semipermeable nature of the barrier to interspecific gene flow provides a valuable framework to identify the genes involved in hybrid mort...
This poster explores the extent of introgression from domestic strains into wild editerranean populations of the brown trout (Salmo trutta L.) and how introgression may vary across the genome of the recipient populations.
This research explores the genomic basis of skin color variation between the Atlantic and Mediterranean lineages of the brown trout (Salmo trutta L.), and shows that wild Mediterranean populations of brown trout supplemented with the foreign Atlantic lineage have intermediate colour patterns compared to ’pure’ populations.
Parallel divergence across replicated species pairs occurring in similar environmental contrastsmay arise through distinct evolutionary scenarios. Deciphering whether such parallelism actually reflects repeated parallel divergence driven by divergent selection or a single divergence event with subsequent gene flow needs to be ascertained. Reconstru...
High-density linkage maps are valuable tools for conservation and eco-evolutionary issues. In salmonids, a complex rediploidization process consecutive to an ancient whole genome duplication event makes linkage maps of prime importance for investigating the evolutionary history of chromosome rearrangements. Here, we developed a high-density consens...
Understanding the evolutionary mechanisms generating parallel genomic divergence patterns among replicate ecotype pairs remains an important challenge in speciation research. We investigated the genomic divergence between the anadromous parasitic river lamprey (Lampetra fluviatilis) and the freshwater-resident non-parasitic brook lamprey (Lampetra...
In marine fishes, the extent to which spatial patterns induced by selection remain stable across generations remains largely unknown. In the gilthead sea bream Sparus aurata, polymorphisms in the growth hormone (GH) and prolactin (Prl) genes can display high levels of differentiation between marine and lagoon habitats. These genotype-environment as...
Hybrid zones provide natural experiments where new combinations of genotypes and phenotypes are produced. Studying the reshuffling of genotypes and remodeling of phenotypes in these zones is of particular interest to document the building of reproductive isolation and the possible emergence of transgressive phenotypes that can be a source of evolut...
A genome-wide assessment of diversity is provided for wild Mediterranean brown trout Salmo trutta populations from headwater tributaries of the Orb River and from Atlantic and Mediterranean hatchery-reared strains that have been used for stocking. Double-digest restriction-site-associated DNA sequencing (dd-RADseq) was performed and the efficiency...
Highly fecund marine species with dispersive life-history stages often display large population sizes and wide geographic distribution ranges. Consequently, they are expected to experience reduced genetic drift, efficient selection fueled by frequent adaptive mutations, and high migration loads. This has important consequences for understanding how...
The brown trout Salmo trutta L. is a widely distributed Eurasian species which has been heavily impacted by human activities, including traditional stocking of hatchery strains to enhance local populations. Understanding the consequences of stocking practices needs a better characterisation of genetic variation. A genome-wide assessment of diversit...
Ecophenotypic differentiation among replicate ecotype pairs within a species complex is often attributed to independent outcomes of parallel divergence driven by adaptation to similar environmental contrasts. However, the extent to which parallel phenotypic and genetic divergence patterns have emerged independently is increasingly questioned by pop...
Linking population genetic variation to the spatial heterogeneity of the environment is of fundamental interest to evolutionary biology and ecology, in particular when phenotypic differences between populations are observed at biologically small spatial scales. Here, we applied restriction-site associated DNA sequencing (RAD-Seq) to test whether ph...
Parallel changes in body shape may evolve in response to similar environmental conditions, but whether such parallel phenotypic changes share a common genetic basis is still debated. The goal of this study was to assess if parallel phenotypic changes could be explained by genetic parallelism, multiple genetic routes or both. We first provide eviden...
Background The two North Atlantic eel species, the European and the American eel, represent an ideal system in which to study parallel selection patterns due to their sister species status and the presence of ongoing gene flow. A panel of 80 coding-gene SNPs previously analyzed in American eel was used to genotype European eel individuals (glass ee...
Major histocompatibility (MHC) immune system genes may evolve in response to pathogens in the environment. Because they also may affect mate choice, they are candidates for having great importance in ecological speciation. Here, we use next-generation sequencing to test the general hypothesis of parallelism in patterns of MHCIIβ diversity and bacte...
When incompletely isolated taxa coexist in a patchy environment (e.g. mosaic hybrid zones, host races), patterns of variation may differ between selected traits/genes and neutral markers. While the spatial structure of selected traits/loci tends to coincide with habitat variables (Genetic-Environment Association or GEA), genetic differentiation at...
When incompletely isolated taxa coexist in a patchy environment (e.g. mosaic hybrid zones, host-race complexes), patterns of variation may differ between selected traits/genes and neutral markers. While the genetic structure of selected traits/loci tends to coincide with habitat variables (producing Genetic-Environment Association or GEA), genetic...
We performed population genetic analyses on the American eel (Anguilla rostrata) with three main objectives. First, we conducted the most comprehensive analysis of neutral genetic population structure to date to revisit the null hypothesis of panmixia in this species. Second, we used this data to provide the first estimates of contemporary effectiv...
The evolution of reproductive isolation in an ecological context may involve multiple facets of species divergence on which divergent selection may operate. These include variation in quantitative phenotypic traits, regulation of gene expression, and differential transmission of particular allelic combinations. Thus, an integrative approach to the...
The genetic basis and evolutionary implications of local adaptation in high gene flow marine organisms are still poorly understood. In several Mediterranean fish species, alternative migration patterns exist between individuals entering coastal lagoons that offer favourable conditions for growth and those staying in the sea where environmental cond...
During their larval leptocephalus phase, newly hatched American eels undergo an extensive oceanic migration from the Sargasso Sea toward coastal and freshwater habitats. Their subsequent metamorphosis into glass eel is accompanied by drastic morphological and physiological changes preceding settlement over a wide geo-graphic range. The main objecti...
In the marine environment, differential gene exchange between partially reproductively isolated taxa can result in introgression that extends over long distances due to high larval dispersal potential. However, the degree to which this process contributes to interlocus variance of genetic differentiation within introgressed populations remains uncl...
Aim The objective of this study was to reveal the present population structure and infer the gene-flow history of the Indo-Pacific tropical eel Anguilla bicolor. Location The Indo-Pacific region. Methods The entire mitochondrial control region sequence and the genotypes at six microsatellite loci were analysed for 234 specimens collected from eight...
Definition of the genus Calliptamus (Orthoptera: Acrididae) has generated many taxonomic debates. Even now, the existence of different geographical morphs hinders species determination, particularly as concerns females and larvae. Some of these species are observed in southern France and are recognized as potential pests. To circumvent problems of...
The occurrence of Alexandrium catenella related to paralytic shellfish poisoning (PSP) in the French Mediterranean Thau lagoon has been known since 1998. Blooms are recurrent and usually occur each year in spring and/or autumn. Taxonomic diversity of resting cysts and vegetative cells has been studied through morphological examination and molecular...
Two morphological characters were examined in 4099 anguillid glass eels sampled in four south-western Indian Ocean islands, and resulting identifications were tested using genetic analysis. Distance between the origin of the dorsal and anal fins as related to total length and tail and caudal fin pigmentation enabled formulation of a useful field id...
Investigating patterns of genetic variation in hybridizing species provides an opportunity to understand the impact of natural selection on intraspecific genetic variability and interspecific gene exchange. The Atlantic eels Anguilla rostrata and A. anguilla each occupy a large heterogeneous habitat upon which natural selection could differentially...
Understanding the evolutionary processes underlying population structuring of freshwater eels is an essential step toward comprehending their exceptional life cycle. However, in order to infer evolutionary scenarios that account for the genetic structure of current populations, it is necessary to unravel the history of gene flow from the onset of p...
The oceanic early-life history of Anguilla marmorata was examined in the southwestern Indian Ocean in Mayotte, Mauritius, and Re´union islands through otolith microstructural analysis. The study of the hatching dates, the first feeding check diameter (FFD), the leptocephalus (LD) and metamorphosis (MD) durations, the age at recruitment (AR), and th...
A total of 4,172 freshwater eels have been collected by electrofishing in upper estuaries from Madagascar (East coast), Mascarene (Réunion and Mauritius Is.), Comoros (Mayotte Is.) and Seychelles (Mahé and Praslin Is.) Archipelagos, between October 2003 and February 2006. Eel species composition in the sampling stations was contrasted between easte... | https://www.researchgate.net/profile/Pierre-Alexandre-Gagnaire |
An assumption central to many tests of statistical association between two variables is the null expectation of zero association. Here, we draw attention to the fact that in many published tests of mass-dependent mass loss in breeding birds, this assumption has been violated. We show that a correct null hypothesis can be derived by using resampling methods, and analyse three data sets (two previously published) from passerine birds to illustrate the approach. Our results show, that under a correct null hypothesis, the biological interpretation of the previously published results is reversed-initially heavy birds do actually lose less mass (relative to their weight) than the initially light birds.
Although the practice of releasing fish into the wild is common in the management and conservation of fish populations, the success of release programmes and the potential harmful genetic and ecological effects that may follow are rarely considered. This thesis focuses on genetic and ecological consequences of fish releases, exemplified by supportive breeding of brown trout (Salmo trutta) and translocation of European eel (Anguilla anguilla). Specific questions addressed include: What is the relative performance of hatchery produced fish released to support wild populations, and do released hatchery fish contribute to the natural productivity? What is the variation in reproductive success in the wild, and how does it affect the genetic consequences of a supportive breeding programme? Is there a spatial genetic structure in the European eel that must be considered in the management of this rapidly declining species?
Experiments conducted under natural and near-natural conditions in the River Dalälven, Sweden, suggest that hatchery produced trout can reproduce in the wild. In fact, when the pronounced variation between individual breeders was accounted for, there were no detectable differences between hatchery produced and wild born trout in reproductive success or offspring survival. These results were supported by molecular genetic data suggesting a pronounced gene flow from hatchery to wild trout in the river. Hatchery reared trout were, however, found to exhibit reduced survival rates immediately following release into the wild, an effect that was most likely due to phenotypic responses to the hatchery environment during ontogeny and a lack of experience of the wild.
In sharp contrast to recently published studies, the present genetic analyses of European eels sampled across the whole distribution range suggest no spatial genetic structure but a subtle temporal genetic heterogeneity within sampled locations. These results emphasise the need to consider temporal replication when assessing population structure of marine species.
The results obtained have general implications for the management and conservation of fish populations. First, supportive breeding of threatened salmonid populations might be successful, not only for boosting the census size and thereby reducing the short-term probability of extinction, but also for reducing the risks of inbreeding depression and loss of adaptive potential in future generations. However, the results also highlight the need to restore the natural productivity of a population under supportive breeding to avoid a potential reduction in fitness due to hatchery selection. Further, the lack of a detectable spatial genetic structure in the European eel suggests that the management strategy of translocating juvenile eels from locations were they are overabundant to other suitable freshwater habitats does not necessarily have to include genetic considerations with respect to the geographical origin of the translocated eels.
1.Although releases of hatchery-produced salmonids to support conspecific wildpopulations have increased dramatically during recent decades, little information isavailable about the performance in the wild of hatchery fish and their offspring.Important factors determining the success and genetic outcomes of supportive breedingprogrammes include (i) the relative reproductive success of released hatchery fish in thewild, and (ii) the extent to which the propagation affects the variance in reproductivesuccess in the population as a whole.2.We performed two field experiments on brown troutSalmo truttafrom the RiverDalälven in Sweden, where we examined reproductive success in an experimental stream.In experiment 1 we compared reproductive success between trout from a seventhgenerationhatchery stock of native origin and wild-born trout from the river. In experiment2, we compared reproductive success between seventh-generation hatchery troutand hatchery-reared trout derived from wild-born parents. Individual reproductivesuccess, based on the number of offspring assigned using microsatellite markers, wasassessed on three occasions after reproduction: immediately after hatching and after thefirst and second growth seasons.3.In experiment 1 there were no significant differences in reproductive success betweenseventh-generation hatchery trout and wild-born trout. In experiment 2, males from wildbornparents were more successful than males from the seventh-generation hatcherystock, but this difference was not observed among females.4.There was some evidence for a positive association between body size and reproductivesuccess among females but not males. For males, the number of mates was significantlyassociated with reproductive success, but this relationship was not evident among females.5.The variance in reproductive success was pronounced in both experiments, yieldingestimates of the ratio between the genetically effective size and the census size of ourexperimental populations ranging from 0·12 to 0·59.6.Synthesis and applications. Our results suggest that the reproductive success in thewild of hatchery-produced and wild-born trout with a common genetic backgroundmay be rather similar. These findings, in combination with the pronounced variancein reproductive success observed among breeders, indicate that supportive breedingcan be managed to increase not only the census but also the genetically effective sizeof small, endangered salmonid populations. However, to minimize negative effects ofhatchery selection, it is important to give priority to the restoration of natural habitatsand thereby increase the reproductive output from individuals in the wild.
This thesis examines risk management in breeding Siberian jays (Perisoreus infaustus), which is indigenous to the northern taiga. Parent behaviour and the nest are cryptic. A new nest is built each year. It is placed on spruce or pine branches close to the trunk and well insulated with lichens, feathers and reindeer hair.
Nest failure rate was the main factor driving annual variations in jay numbers. The probability for nesting attempts to be successful ranged annually between 0.08 and 0.70. Nest predation was rampant and a main cause of nest failure. Nest predators were mainly other corvids (primarily the Eurasian jay Garrulus glandarius). Habitat quality was the main factor determining the risk of predation. The risk for nest failure due to predation was higher in thinned forests with an open structure and with a high abundance of man-associated corvid species (jays, crows, raven).
Siberian jay parents show several strategic adjustments in life-history and behaviour to the risk of nest predation. Parents traded reduced feeding rates for a lower predation risk and allocated feeding to low risk situations. Chick provisioning imposes a cost by drawing the attention of visually hunting predators to the location of nests, and parents adjusted their daily routines and avoided exposure by allocating provisioning to times of low activity among nest predators. These strategic adjustments of feeding efforts were estimated to reduce the exposure to nest predators by 26 percent. Also, parents adjusted their reproductive efforts to the perceived presence of predators in a playback experiment. Siberian jays reduced their reproductive investment by laying a smaller clutch size when high risk of nest predation reduced the value of current reproduction, as predicted from life-history theory.
Genes of the major histocompatibility complex (MHC) play a major part in the activation of the vertebrate immune system. In addition, they also appear to function as cues for mate choice. In mammals especially, several kinds of MHC-dependent mate choice have been hypothesized and observed. These include choice of mates that share no or few alleles with the choosing individual, choice of mates with alleles that differ as much as possible from the choosing individual, choice of heterozygous mates, choice of certain genotypes and choice of rare alleles. We investigated these different aspects of mate choice in relation to MHC in a lekking bird species, the great snipe (Gallinago media). We found no evidence for MHC disassortative mating, no preference for males with many MHC alleles and no preference for rare alleles. However, we did find that some allelic lineages were more often found in males with mating success than in males without mating success. Females do not seem to use themselves as references for the MHC-dependent mate choice, rather they seem to prefer males with certain allele types. We speculate that these alleles may be linked to resistance to common parasites.
Parasites and diseases constitute major evolutionary forces in many natural populations, and thus having an efficient immune defense to resist infections is crucial for many organisms. Properties of the immune response may also influence mate choice decisions in many animals. Theory predicts several advantages for females when choosing males with superior immune systems. These benefits can be both direct (e.g. increased paternal care and reduced disease transmission) and indirect (good genes). We have investigated female choice with respect to antibody response to two novel antigens in males of a lekking bird, the great snipe (Gallinago media). Because of the lek mating system, female choice probably mainly incurs indirect (genetic) rather than direct benefits. Males responded to vaccination with diphtheria and tetanus toxoids by producing specific antibodies to both antigens. Triggering the immune system had no negative impact on display activities or survival. Males that were chosen by females as mates had on average higher antibody response to the tetanus antigen than their neighbors. We did not, however, find any covariance between the strength of the antibody response and male mating success.
From a life history perspective, parents have an incentive to protect their reproductive investment, and so may provide care even after their offspring are independent. Such prolonged parental care could lead to postponed dispersal of the offspring and thereby facilitate the formation of kin groups. We tested whether alpha birds in Siberian jays protected their independent, retained offspring by giving alarm calls during simulated predator attacks. We compared the responses to predator attacks simulated by flying a hawk model over a dyad of birds on a feeder for dyads composed of an alpha bird and either a relative or a nonrelative. Alpha females were nepotistic in their alarm-calling behaviour, in that they called more frequently when accompanied by their retained offspring than by unrelated immigrants, but alpha males called indiscriminately. This difference in alarm calling could reflect dominance relationships in Siberian jay groups, because the presence of immigrants may be less costly to alpha males, but alpha females are more vulnerable to competition from immigrants. Alarm calls were usually given during escape, when both individuals in the dyad had left the feeding site. However, results of a playback experiment suggest that alarm calls conveyed information about danger and incited an immediate escape reaction. Our results indicate that alarm calling can be nepotistic, and that factors other than kinship influence alarm-calling behaviour. Nepotistic antipredator behaviours are benefits that offspring can gain only in their natal territory. Hence, in the absence of preferential treatment by their parents, offspring may be more likely to disperse and kin groups are prevented from forming.
We manipulated brood sizes of 132 pairs of the collared flycatcher to investigate whether or not an investment in reproduction was traded against an investment and timing of the post-nuptial moult. Our manipulations did not affect the probability of moult-breeding overlap in males, and there was no effect on their moult scores at fledging time of the young. Males and young birds initiated moult earlier than females and old birds, respectively. Very few females started moulting during the period of nestling care. Reproductive success in terms of recruitment rate of fledglings was independent of parental moult stage during reproduction, which indicates that the manipulation did not induce a trade-off between moult and post-fledging care. Furthermore, the survival probability of adults was independent of brood size manipulations and their moult stage at fledging time. Thus, our brood size manipulations showed no evidence for a trade-off between reproductive and moult investments in the collared flycatcher.
Genetic variability in quantitative traits can change as a direct response to the environmental conditions in which they are expressed. Consequently, similar selection in different environments might not be equally effective in leading to adaptation. Several hypotheses, including recent ones that focus on the historical impact of selection on populations, predict that the expression of genetic variation will increase in unfavourable conditions. However, other hypotheses lead to the opposite prediction. Although a consensus is unlikely, recent Drosophila and bird studies suggest consistent trends for morphological traits under particular conditions.
Using independently segregating nuclear single nucleotide polymorphisms (SNPs) and mitochondrial control region sequences, we found an east-west division among sampled willow grouse Lagopus lagopus subspecies. This division cut across the range of the subspecies with the largest distribution (lagopus) and thus contradicted existing taxonomic classifications. Russian Lagopus lagopus lagopus tended to cluster with North American willow grouse partly classified as other subspecies. Scandinavian willow grouse (L.l. lagopus) clustered with red grouse from Britain and Ireland (Lagopus lagopus scoticus and Lagopus lagopus hibernicus) but substructuring confirmed the monophyly of the latter. In North America, we could not detect any major genetic divisions apart from two birds described as alexandrae from the Heceta Island (Alaska) when using mitochondrial sequences. Other samples from North America were intermingled regardless of whether they were described as muriei, alexandrae or lagopus. A specimen described as alexandrae was to some extent distinct when analysing the SNP data. The genetic analyses indicated some concordance between genetics and taxonomy but not complete congruence. This is particularly evident for mitochondrial DNA network analyses. We suggest that the taxonomy of this species would benefit by a careful re-examination of the available evidence for subspecies. It appears as if subspecies status is a poor proxy for assigning evolutionary significant units and management units in this species.
Sexual conflict is said to occur when one mating partner has an opportunity to increase its fitness at the cost of the other. We analyzed the effect of remarriage on lifetime reproductive success (LRS) in three preindustrial (1700–1900) socially monogamous Sami populations. In all populations, ever-married women’s age-specific mortality rates exceeded those of ever-married men during reproductive years. After the death of a spouse, men had a higher probability of remarriage than did women of the same age. Remarried men had a higher LRS than men who married only once, but this was not true for women. The higher LRS of the twice-married men was probably due to their longer (+5 years; p < .05) reproductive lifespan (RLS) as compared to once-married men. There was no difference in the RLS of women who married once or twice. These results suggest the sexual conflict in these populations was won by men because women paid a higher cost from reproduction (i.e., reduced survival), and men were able to remarry more often than women, thereby realizing more of their higher reproductive potential. Consequently, serial monogamy seem to have been an important male reproductive strategy in these historical populations.
Questions: Does intraspecific extension of Bergmanns rule – larger size within a species incooler areas – hold true for ectotherms in general, and for the common frog (Rana temporaria)in particular? What is the relative importance of genetic and environmental factors (i.e. directenvironmental induction) in determining latitudinal patterns of body size variation in commonfrogs?Methods: We tested for a positive association between mean body size and latitude incommon frogs (Rana temporaria) across a 1600 km long latitudinal gradient in Scandinaviaboth for wild-collected adults and laboratory-reared metamorphs.Results: In adults, the mean body size increased from south to mid-latitudes, and declinedthereafter. This occurred despite the fact that the mean age of adult frogs increased withincreasing latitude, and age and body size were positively correlated. The latitudinal pattern ofbody size variation in metamorphs reared in a common garden experiment was similar to thatobserved among wild-caught adults.Conclusions: The results suggest that the concave pattern of body size variation across thelatitudinal cline may be at least partly genetically determined, and that although there isconsiderable geographic variation in mean body size of R. temporaria, this variation does notconform with Bergmann’s rule.
Variation in seasonal time constraints and temperature along latitudinal gradients are expected to select for life history trait differentiation, but information about the relative importance of these factors in shaping patterns of divergence in embryonic traits remains sparse. We studied embryonic survival, growth and development rates in the common frog (Rana temporaria) along a 1,400-km latitudinal gradient across Sweden by raising embryos from four populations in the laboratory at seven temperatures (9 degrees C, 12 degrees C, 15 degrees C, 18 degrees C, 21 degrees C, 24 degrees C, 27 degrees C). We found significant differences in mean values of all traits between the populations and temperature treatments, but this variation was not latitudinally ordered. In general, embryonic survival decreased at the two highest temperatures in all populations, but less so in the southernmost as compared to the other populations. The northernmost population developed slowest at the lowest temperature, while the two mid-latitude populations were slowest at the other temperatures. Hatchling size increased with increasing temperature especially in the two northern populations, whereas the two southern populations showed peak hatchling size at 15 degrees C. Analyses of within-population genetic variation with a half-sib design revealed that there was significant additive genetic variation in all traits, and egg size-related maternal effects were important in the case of hatchling size. Overall, our results indicate that unlike larval growth and development, variation in embryonic development and growth in R. temporaria cannot be explained in terms of a latitudinal gradient in season length. While adaptation to a latitudinal variation in temperature might have contributed to the observed differentiation in embryonic performance, the effects of other, perhaps more local environmental factors, seem to have overridden them in importance.
The relative importance of genetic, environmental, and maternal effects as determinants of geographical variation in vertebrate life-histories has not often been explored. We examined the role of genetic and maternal effects as determinants of population divergence in survival and three important larval life-history traits (growth rate, age, and size at metamorphosis) using reciprocal crosses between two latitudinally separated populations of the common frog (Rana temporaria Linnaeus). Genetic effects were important in all three traits as indicated by the significant effect of male origin, but there was also evidence for nonadditive genetic contributions on metamorphic size and growth rate. Likewise, maternal effect contributions to population divergence were large, partially environment dependent, and apparently acting primarily through egg size in two of three traits. These results suggest that both genetic and maternal effects are important determinants of geographical variation in amphibian life-histories, and that much of the differentiation resulting from maternal effects is mediated through variation in egg size.
Adaptive genetic differentiation along a climatic gradient as a response to natural selection is not necessarily expressed at phenotypic level if environmental effects on population mean phenotypes oppose the genotypic effects. This form of cryptic evolution--called countergradient variation--has seldom been explicitly demonstrated for terrestrial vertebrates. We investigated the patterns of phenotypic and genotypic differentiation in developmental rates of common frogs (Rana temporaria) along a ca. 1600 km latitudinal gradient across Scandinavia. Developmental rates in the field were not latitudinally ordered, but displayed large variation even among different ponds within a given latitudinal area. In contrast, development rates assessed in the laboratory increased strongly and linearly with increasing latitude, suggesting a genetic capacity for faster development in the northern than the southern larvae. Experiments further revealed that environmental effects (temperature and food) could easily override the genetic effects on developmental rates, providing a possible mechanistic explanation as to why the genetic differentiation was not seen in the samples collected from the wild. Our results suggest that the higher developmental rates of the northern larvae are likely to be related to selection stemming from seasonal time constrains, rather than from selection dictated by low ambient temperatures per se. All in all, the results provide a demonstration of environmental effects concealing substantial latitudinally ordered genetic differentiation understandable in terms of adaptation to clinal variation in time constrains.
The main aim of this work was to identify local adaptation processes in amphibian populations, thereby improving the general understanding of genetics and mechanisms behind the evolution and maintenance of biological diversity. Phenotypic and genetic variation in life-history traits was studied within and between populations common frog (Rana temporaria) populations along a 1600 km transect from southern Sweden to northern Finland.
Embryonic and larval development and growth was investigated both under field and laboratory conditions. The results suggest ample genetic diversity in larval life-history traits among Fennoscandian common frog populations. Larval developmental rate along the gradient has evolved a countergradient variation pattern of genotypes and phenotypes as indicated by the positive relationship between developmental rate and latitude under laboratory conditions and the lack of such a relationship in the field. The data suggest that this pattern has evolved because of time constraints due to decreasing length of growth season with latitude. Neither field-caught adults nor laboratory raised larvae displayed a linear latitudinal size cline as expected from the so called Bergmanns rule. Rather, size increased towards the mid-latitude populations and decreased thereafter, indicating that body size is a product of direct environmental induction or a trade-off with other life-history characters. Age and size at hatching showed no consistent latitudinal pattern, indicating that the embryonic stage is not as time constrained as the larval stage.
A large part of the variation in age and size at metamorphosis among populations was due to additive genetic effects. However, small, but significant maternal effects, mostly due to variation in egg size and non-additive genetic effects also contributed to among population variation. A comparison of divergence in presumably neutral molecular genetic markers (FST) and quantitative characters (QST) revealed that although both estimates of divergence were relatively high, estimates of QST was generally higher than those of FST, indicating that the genetic variation observed in larval traits is primarily a result of natural selection rather than genetic drift. Hence, our results reinforce the conclusion that intraspecific genetic heterogeneity in the young northern European ecosystems may be more widespread than previously anticipated
The relative roles of natural selection and direct environmental induction, as well as of natural selection and genetic drift, in creating clinal latitudinal variation in quantitative traits have seldom been assessed in vertebrates. To address these issues, we compared molecular and quantitative genetic differentiation between six common frog (Rana temporaria) populations along an approximately 1600 km long latitudinal gradient across Scandinavia. The degree of population differentiation (QST approximately 0.81) in three heritable quantitative traits (age and size at metamorphosis, growth rate) exceeded that in eight (neutral) microsatellite loci (FST = 0.24). Isolation by distance was clear for both neutral markers and quantitative traits, but considerably stronger for one of the three quantitative traits than for neutral markers. QST estimates obtained using animals subjected to different rearing conditions (temperature and food treatments) revealed some environmental dependency in patterns of population divergence in quantitative traits, but in general, these effects were weak in comparison to overall patterns. Pairwise comparisons of FST and QST estimates across populations and treatments revealed that the degree of quantitative trait differentiation was not generally predictable from knowledge of that in molecular markers. In fact, both positive and negative correlations were observed depending on conditions where the quantitative genetic variability had been measured. All in all, the results suggest a very high degree of genetic subdivision both in neutral marker genes and genes coding quantitative traits across a relatively recently (< 9000 years) colonized environmental gradient. In particular, they give evidence for natural selection being the primary agent behind the observed latitudinal differentiation in quantitative traits.
Comparative studies of the genetic architecture of different types of traits were initially prompted by the expectation that traits under strong directional selection (fitness traits) should have lower levels of genetic variability than those mainly under weak stabilizing selection (nonfitness traits). Hence, early comparative studies revealing lower heritabilities of fitness than nonfitness traits were first framed in terms of giving empirical support for this prediction, but subsequent treatments have effectively reversed this view. Fitness traits seem to have higher levels of additive genetic variance than nonfitness traits — an observation that has been explained in terms of the larger number loci influencing fitness as compared to nonfitness traits. This hypothesis about the larger functional architecture of fitness than nonfitness traits is supported by their higher mutational variability, which is hard to reconcile without evoking capture of mutational variability over many loci. The lower heritabilities of fitness than nonfitness traits, despite the higher additive genetic variance of the former, occur because of their higher residual variances. Recent comparative studies of dominance contributions for different types of traits, together with theoretical predictions and a large body of indirect evidence, suggest an important role of dominance variance in determining levels of residual variance for fitness-traits. The role of epistasis should not be discounted either, since a large number of loci increases the potential for epistatic interactions, and epistasis is strongly implicated in hybrid breakdown.
Understanding the diversity of life is one of the main aims of evolutionary biology, and requires knowledge of the occurrence and causes of adaptive genetic differentiation among geographically distinct populations. Environmental stress caused by acidity may cause strong directional selection in natural populations, but is little explored from an evolutionary perspective. In this thesis, a series of laboratory experiments and field data was used to study evolutionary and ecological responses of amphibians to environmental acidity.
Local adaptation to acid stress was studied in the moor frog (Rana arvalis).The results show that acid origin populations have higher acid stress tolerance during the embryonic stages than neutral origin populations, and that acid and neutral origin populations have diverged in embryonic and larval life-histories. The mechanisms underlying adaptive differentiation are partially mediated by maternal effects related to extra-embryonic membranes and egg size. Acid origin females invest in larger eggs and have a stronger egg size-fecundity trade-off than females from neutral areas, likely reflecting adaptive differentiation in maternal investment patterns.
Potential carry-over effects of low pH, and the effects of UV-b/pH interaction were investigated in the common frog (R. temporaria). The results suggest that amphibian larvae are able to compensate for the negative effects of acidity experienced early in life, if conditions later turn beneficial. R. temporaria populations differed in their sensitivity to synergistic effects of low pH/UV-B, indicating variation in population responses to environmental stress.
In conclusion, these results suggest rapid evolution in response to human induced environmental change, much of which may be mediated via adaptive maternal effects. Acidification may be a powerful selective force shaping life-history evolution.
Genetic structuring is common in natural populations. It is important to identify and consider population structure when studying evolutionary processes. Recently, the discovery of genetic structuring in some lekking bird species has opened up new perspectives on our understanding of the evolution of lek mating systems.
This thesis uses molecular data to identify patterns of broad and fine scale genetic structuring in the lekking white-bearded manakin Manacus manacus. Additionally, data on male mating success, female visiting patterns and behavioural, morphological and territorial characteristics of individual males are used to identify variables that may influence the distribution of matings in this species.
Analysis of genetic divergence within the genus Manacus revealed genetic sub-structuring and limited gene flow between species/subspecies. There was no significant isolation by distance relationship. Factors such as physical barriers to gene flow may play a role in shaping the genetic structure of the bearded manakin genus.
White-bearded manakin leks on Trinidad were composed of groups of related males. More than one such kin group existed on each lek. That related males gather in groups suggests that genetic structuring is not simply a consequence of limited dispersal. Active choices must take place by both residential and newly arrived birds.
Female visits to, and matings with, males were non-random. Centrality of male display court was the only measured variable that consistently correlated with male mating success. More aggressive displays were made as the distance between courts decreased. There was no significant relationship between the number of aggressive displays made between males and relatedness levels. Males with high mating success spent more time in aggressive behaviours.
In conclusion, white-bearded manakin lek formation and display court acquisition is likely to be influenced by genetic relatedness levels and male-male interactions. Centrality of court seemed important in mating success and may be an indicator of male dominance. However, a variety of other factors may also influence mating success and may be variable over time.
The black grouse (Tetrao tetrix) is a galliform bird species that is important forboth ecological studies and conservation genetics. Here, we report the sequencing of the spleen transcriptome of black grouse using 454 GS FLX Titanium sequencing. We performed a large-scale gene discovery analysis with a focus on genes that might be related to fitness in this species and also identified a large set of microsatellites. In total, we obtained 182 179 quality-filtered sequencing reads that we assembled into 9035 contigs. Using these contigs and 15 794 length-filtered (greater than 200 bp) singletons, we identified 7762 transcripts that appear to be homologues of chicken genes. A specific BLAST search with an emphasis on immune genes found 308 homologous chicken genes that have immune function, including ten major histocompatibility complex-related genes located on chicken chromosome 16. We also identified 1300 expressed sequence tag microsatellites and were able to design suitable flanking primers for 526 of these. A preliminary test of the polymorphism of the microsatellites found 10 polymorphic microsatellites of the 102 tested. Genomic resources generated in this study should greatly benefit future ecological, evolutionary and conservation genetic studies on this species. | http://uu.diva-portal.org/smash/resultList.jsf?af=%5B%5D&aq=%5B%5B%7B%22organisationId%22%3A%221133%22%7D%5D%5D&aqe=%5B%5D&aq2=%5B%5B%5D%5D&language=en&query= |
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary.
Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals.
The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitutions. Diversifying selection is the hypothesis that two subpopulations of a species live in different environments that select for different alleles at a particular locus. This may occur, for instance, if a species has a large range relative to the mobility of individuals within it. Frequency-dependent selection is the hypothesis that as alleles become more common, they become more vulnerable. This occurs in host–pathogen interactions, where a high frequency of a defensive allele among the host means that it is more likely that a pathogen will spread if it is able to overcome that allele.
|Part of a series on|
|Evolutionary biology|
A study conducted by the National Science Foundation in 2007 found that genetic diversity (within species diversity) and biodiversity are dependent upon each other — i.e. that diversity within a species is necessary to maintain diversity among species, and vice versa. According to the lead researcher in the study, Dr. Richard Lankau, "If any one type is removed from the system, the cycle can break down, and the community becomes dominated by a single species." Genotypic and phenotypic diversity have been found in all species at the protein, DNA, and organismal levels; in nature, this diversity is nonrandom, heavily structured, and correlated with environmental variation and stress.
The interdependence between genetic and species diversity is delicate. Changes in species diversity lead to changes in the environment, leading to adaptation of the remaining species. Changes in genetic diversity, such as in loss of species, leads to a loss of biological diversity. Loss of genetic diversity in domestic animal populations has also been studied and attributed to the extension of markets and economic globalization.
Variation in the populations gene pool allows natural selection to act upon traits that allow the population to adapt to changing environments. Selection for or against a trait can occur with changing environment – resulting in an increase in genetic diversity (if a new mutation is selected for and maintained) or a decrease in genetic diversity (if a disadvantageous allele is selected against). Hence, genetic diversity plays an important role in the survival and adaptability of a species. The capability of the population to adapt to the changing environment will depend on the presence of the necessary genetic diversity The more genetic diversity a population has, the more likelihood the population will be able to adapt and survive. Conversely, the vulnerability of a population to changes, such as climate change or novel diseases will increase with reduction in genetic diversity. For example, the inability of koalas to adapt to fight Chlamydia and the koala retrovirus (KoRV) has been linked to the koala's low genetic diversity. This low genetic diversity also has geneticists concerned for the koalas' ability to adapt to climate change and human-induced environmental changes in the future.
Large populations are more likely to maintain genetic material and thus generally have higher genetic diversity. Small populations are more likely to experience the loss of diversity over time by random chance, which is called genetic drift. When an allele (variant of a gene) drifts to fixation, the other allele at the same locus is lost, resulting in a loss in genetic diversity. In small population sizes, inbreeding, or mating between individuals with similar genetic makeup, is more likely to occur, thus perpetuating more common alleles to the point of fixation, thus decreasing genetic diversity. Concerns about genetic diversity are therefore especially important with large mammals due to their small population size and high levels of human-caused population effects.
A genetic bottleneck can occur when a population goes through a period of low number of individuals, resulting in a rapid decrease in genetic diversity. Even with an increase in population size, the genetic diversity often continues to be low if the entire species began with a small population, since beneficial mutations (see below) are rare, and the gene pool is limited by the small starting population. This is an important consideration in the area of conservation genetics, when working toward a rescued population or species that is genetically-healthy.
Random mutations consistently generate genetic variation. A mutation will increase genetic diversity in the short term, as a new gene is introduced to the gene pool. However, the persistence of this gene is dependent of drift and selection (see above). Most new mutations either have a neutral or negative effect on fitness, while some have a positive effect. A beneficial mutation is more likely to persist and thus have a long-term positive effect on genetic diversity. Mutation rates differ across the genome, and larger populations have greater mutation rates. In smaller populations a mutation is less likely to persist because it is more likely to be eliminated by drift.
Gene flow, often by migration, is the movement of genetic material (for example by pollen in the wind, or the migration of a bird). Gene flow can introduce novel alleles to a population. These alleles can be integrated into the population, thus increasing genetic diversity.
For example, an insecticide-resistant mutation arose in Anopheles gambiae African mosquitoes. Migration of some A. gambiae mosquitoes to a population of Anopheles coluzziin mosquitoes resulted in a transfer of the beneficial resistance gene from one species to the other. The genetic diversity was increased in A. gambiae by mutation and in A. coluzziin by gene flow.
When humans initially started farming, they used selective breeding to pass on desirable traits of the crops while omitting the undesirable ones. Selective breeding leads to monocultures: entire farms of nearly genetically identical plants. Little to no genetic diversity makes crops extremely susceptible to widespread disease; bacteria morph and change constantly and when a disease-causing bacterium changes to attack a specific genetic variation, it can easily wipe out vast quantities of the species. If the genetic variation that the bacterium is best at attacking happens to be that which humans have selectively bred to use for harvest, the entire crop will be wiped out.
The nineteenth-century Great Famine in Ireland was caused in part by a lack of biodiversity. Since new potato plants do not come as a result of reproduction, but rather from pieces of the parent plant, no genetic diversity is developed, and the entire crop is essentially a clone of one potato, it is especially susceptible to an epidemic. In the 1840s, much of Ireland's population depended on potatoes for food. They planted namely the "lumper" variety of potato, which was susceptible to a rot-causing oomycete called Phytophthora infestans. The fungus destroyed the vast majority of the potato crop, and left one million people to starve to death.
Genetic diversity in agriculture does not only relate to disease, but also herbivores. Similarly, to the above example, monoculture agriculture selects for traits that are uniform throughout the plot. If this genotype is susceptible to certain herbivores, this could result in the loss of a large portion of the crop. One way farmers get around this is through inter-cropping. By planting rows of unrelated, or genetically distinct crops as barriers between herbivores and their preferred host plant, the farmer effectively reduces the ability of the herbivore to spread throughout the entire plot.
The genetic diversity of livestock species permits animal husbandry in a range of environments and with a range of different objectives. It provides the raw material for selective breeding programmes and allows livestock populations to adapt as environmental conditions change.
Livestock biodiversity can be lost as a result of breed extinctions and other forms of genetic erosion. As of June 2014, among the 8,774 breeds recorded in the Domestic Animal Diversity Information System (DAD-IS), operated by the Food and Agriculture Organization of the United Nations (FAO), 17 percent were classified as being at risk of extinction and 7 percent already extinct. There is now a Global Plan of Action for Animal Genetic Resources that was developed under the auspices of the Commission on Genetic Resources for Food and Agriculture in 2007, that provides a framework and guidelines for the management of animal genetic resources.
Awareness of the importance of maintaining animal genetic resources has increased over time. FAO has published two reports on the state of the world's animal genetic resources for food and agriculture, which cover detailed analyses of our global livestock diversity and ability to manage and conserve them.
High genetic diversity in viruses must be considered when designing vaccinations. High genetic diversity results in difficulty in designing targeted vaccines, and allows for viruses to quickly evolve to resist vaccination lethality. For example, malaria vaccinations are impacted by high levels of genetic diversity in the protein antigens. In addition, HIV-1 genetic diversity limits the use of currently available viral load and resistance tests.
The natural world has several ways of preserving or increasing genetic diversity. Among oceanic plankton, viruses aid in the genetic shifting process. Ocean viruses, which infect the plankton, carry genes of other organisms in addition to their own. When a virus containing the genes of one cell infects another, the genetic makeup of the latter changes. This constant shift of genetic makeup helps to maintain a healthy population of plankton despite complex and unpredictable environmental changes.
Cheetahs are a threatened species. Low genetic diversity and resulting poor sperm quality has made breeding and survivorship difficult for cheetahs. Moreover, only about 5% of cheetahs survive to adulthood However, it has been recently discovered that female cheetahs can mate with more than one male per litter of cubs. They undergo induced ovulation, which means that a new egg is produced every time a female mates. By mating with multiple males, the mother increases the genetic diversity within a single litter of cubs.
Attempts to increase the viability of a species by increasing genetic diversity is called genetic rescue. For example, eight panthers from Texas were introduced to the Florida panther population, which was declining and suffering from inbreeding depression. Genetic variation was thus increased and resulted in a significant increase in population growth of the Florida Panther. Creating or maintaining high genetic diversity is an important consideration in species rescue efforts, in order to ensure the longevity of a population.
Genetic diversity of a population can be assessed by some simple measures. | https://db0nus869y26v.cloudfront.net/en/Genetic_diversity |
Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to which the pattern observed for allozymes can be used to infer patterns of genetic variation in quantitative traits depends on the forces generating and maintaining variability. Allozyme variation is probably not strictly neutral but, nevertheless, heterozygosity is expected to be influenced by population size and genetic distance will be affected by time since divergence. The same is true for quantitative traits influenced by many genes and under weak stabilizing selection. However, the limited data available suggest that allozyme variability is a poor predictor of genetic variation in quantitative traits within populations. It is a better predictor of general phenotypic divergence and of postzygotic isolation between populations or species, but is only weakly correlated with prezygotic isolation. Studies of grasshopper and planthopper mating signal variation and assortative mating illustrate how these characters evolve independently of general genetic and morphological variation. The role of such traits in prezygotic isolation, and hence speciation, means that they will contribute significantly to the diversity of levels of genetic variation within and among species. | http://eprints.whiterose.ac.uk/93/ |
of the Old World (e.g., Africa, Asia, and Europe). In turn, einkorn wheat (Triticum monococcum L.) is considered a wild relative of wheat (Triticum aestivum L.) and can be used as a source of agronomically important genes for breeding purposes. They know that Africans have the most genetic variation of any human population, and that in fact Africa has more genetic variation than the rest of the world combined. An official website of the United States government. Of course there is some bleed over, but that doesn't change the fact that there are absolutely distinct genetic . T. boeticum). the developing world mainly in the 30 sub Saharan Africa and Asian countries (Kumar et al., 2011), but Dr. Graeme Mardon Examining the genetic diversity underlying differences in skin pigmentation can reveal a great deal about human evolution and population migration patterns.
aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Some polymorphisms of the DRD2/ANKK1 locus (TaqIA, TaqIB, TaqID) have been used to study genetic diversity and the evolution of human populations. Investigating genetic diversity within the most abundant and prevalent non-pathogenic leaf-associated bacteria interacting with Arabidopsis thaliana in natural habitats aegilopoides (syn. For the better utilization . . The SNP density is 1 SNP/1331 bp for the former data and 1 SNP/1123 bp for our data. More women than men have contributed to the gene pool of humanity since the first modern humans walked out of Africa around 70,000 years ago . (valid data mostly limited to the new world and Africa) . The researchers identified a total of 241 . By analyzing current-day genetic data, we can look back into human history. Africans do. For instance, Denisovan DNA accounts for about 2 to 4 percent of the DNA in people native to some Southwest Pacific island nations. Ther researcher Dawit Wolde Meskel takes a skin-reflectance . The general lack of diversity among people is the reason the Out of Africa model has humanity going through a disastrous, near-extinction bottleneck . The present investigation aims to assess the genetic diversity in seven North African populations in order to explore their genetic structure and to compare them to others worldwide populations . There is, for instance, more genetic diversity within Africa than in the rest of the world put together. Genetic material from people of African descent makes up just 2 per cent. A better understanding of the genetic diversity in sorghum would greatly contribute to crop improvement with a view to food quality and other important agronomic traits. Some common genetic variants reach appreciable frequencies (e.g., 30-50 percent) in many of the world's populations. Genetic variation is the difference in DNA among individuals or the differences between populations. The World's Bananas Are Clonesand They Are in Imminent Danger. Analyzing the genetic makeup of 20 Americans of European ancestry and 15 African-Americans, researchers found that the former showed much less variation among 10,000 tested genes than did the . Genetic diversity is a function of a population's "age" (i.e., the amount of time during which mutations accumulate to generate diversity) and its size. The findings help explain the vast range of skin color on the African . The map above, created by eupedia.com, shows the genetic makeup of European countries based on Haplogroups. One more line of evidence crops up in the amount of genetic diversity that has been found within people worldwide. The future of the cheetah not only depends on habitat protection, but also on our ability to help maximize reproductive success with captive and wild cheetahs to maintain genetic diversity. Essentially, much less has been found than most (i.e., evolutionists!) Biodiversity includes plants , animals, fungi, and other living things.
Instead, a survey deemed the "world's largest-ever DNA sequencing of Viking skeletons" reinforces what historians and archaeologists have long speculated: that Vikings' expansion to lands . By Ed Yong. In humans, haplogroups can either be based on Y-DNA which is passed from father to son or mtDNA which is passed from mother to . Organisms that can clone themselves, like bacteria, can pass alleles to each other. A study of diverse people from Africa shows that the genetic story of our skin is more complicated than previously thought. The genetics revealed a new hominin. The geographic region with the greatest genetic diversity = region of origin Eight (8) centers proposed, with some subcenters More philosophical doctrine and very little data to support the 8 centres Launched expeditions around the world to gather all the useful .
Figure 2 - (A) Genetic diversity is generated when mutations create new alleles over time. Kinds of Biodiversity. To help save the world's remaining lions and better understand how the different types are related, an international team of scientists created complete genomes of 20 individual lions, 14 of . 41. Genetic genealogy is the use of genealogical DNA tests, i.e., DNA profiling and DNA testing, in combination with traditional genealogical methods, to infer genetic relationships . The genetic similarities seen in contemporary populations The multiple sources of genetic variation include mutation and genetic recombination. They are known from only a few bits of bone and teeth. Each coloured dot represents a different allele. We can now study the genomes of extant Africans and uncover traces of population migration, admixture, assimilation and selection by applying sophisticated computational algorithms. It has the potential to identify the .
27 January 2016, Rome - Livestock keepers and policy makers worldwide are increasingly interested in harnessing animal biodiversity to improve production and food security on a warmer, more crowded planet, according to a new FAO report issued today. Enormous stingray sets world record for largest freshwater fish. These folk, now known as Denisovans, remain mysterious. Suggestions for future conservation of on-farm genetic diversity and local land-races are further discussed. The researchers found four key areas of the genome where variation closely correlated with skin color differences. The data is helping scientists to understand how susceptibility to disease varies across the. A wide-ranging study published in 2004 found that 87.6% percent of the total modern human genetic diversity isaccounted for by the differences between individuals, and only 9.2% between continents.
Mutations are the ultimate sources of genetic variation, but other mechanisms, such as sexual reproduction and genetic drift, contribute to it, as well. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. The NIH panel consists of 90 individuals from European-Americans, African-Americans, Hispanic Americans, Native Americans, and Asian Americans, while our estimate of 0.089% is from a worldwide sample ( Table 2) and is slightly higher. For example, as genetic diversity of the main tree species is lost, other species, like insects and fungi, that are specifically associated with certain trees may disappear too, leaving the whole forest ecosystem biologically impoverished. Keywords Cacao.Genediversity.Allelicdiversity.
Animals; Animals;
Genetic diversity by region In this study, the tested 768 cowpea accessions, except the Indian accessions, were divided into 9 groups based on their original geographical regions: South Africa, West Africa, Central East Africa, East Asia, Central West Asia, Europe, Oceania, North America, and Latin America; the germplasm accessions from India .
.
Last modified on Wed 14 Feb 2018 16.44 EST. In estimating the impact on economic development of migratory distance from East Africa via its eect on genetic diversity, this research overcomes limitations and potential concerns that are presented by the existing data on genetic diversity across the globe (i.e., measurement error, data limitations, and potential endogeneity). There is, for instance, more genetic diversity within Africa than in the rest of the world put together. Except for genetic differentiation, the average values for gene diversity (h = 0.45) and gene flow (Nm = 2.64) over all loci for the total population in Ethiopia were all significantly higher than the comparable statistics reported by Dalvand et al. monococcum originated from T. monococcum subsp. The study didn't find. Genetic drift can cause big losses of genetic variation for small populations. The banana is the . . Enormous stingray sets world record for largest freshwater fish. Scientists have since tackled topics such as human migrations out of Africa and around the world. The African Genome Variation Project . Our .
The hallmarks of the Out of Africa hypothesis are also addressed by multiregional evolution: Low genetic diversity among human populations is explained through gene-flow rather than recency of origin, and the greater genetic diversity in Africa is explained by larger population size, greater ecological diversity, and natural selection. of the world, especially in Africa, Asia and Latin America.
Ioannis Stergiopoulos, Andr Drenth and Gert Kema. a higher level of african diversity supports the hypothesis that modern humans first arose in africa and then colonized other parts of the world (stoneking 1993 ), but genetic diversity is related not just to a population's "age" but also to demographic events in a population's history, such as bottlenecks and effective population size Genetic nucleotide identity was 99.17% within African camel virus genomes, >99.26% within human and camel MERS-CoV from the Middle East, and 99.18-99.58% between viruses from the Middle East and Africa (GenBank accession nos: MG923465 - MG923481 ). Africans have more genetic variation than anyone else on Earth, according to a new study that helps narrow the location where humans first evolved, probably near the South Africa-Namibia border..
Genotyping by sequencing was used to discover single nucleotide polymorphism (SNP) in cowpea and the identified SNP alleles were used to estimate the level of genetic diversity . The lack of African genetic material constitutes.
predicted. Here's how you know
Global genetic diversity of Aedes aegypti Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. The African replacement hypothesis, sometimes called the ''out of Africa hypothesis,'' suggests that humans evolved into Homo sapiens in Africa and then migrated out into the rest of the Old World . Details of genetic diversity, species diversity and ecosystem diversity are given.
As Matthew Nelson, head of genetics at GlaxoSmithKline, tells me: "If I was able to access a full medical history of 500,000 people across five countries in Africa, and analyse genetic data from . Groups of chimpanzees within central Africa are more different genetically than humans living on different continents, an Oxford University-led study has found. Because humans have lived there longer than anywhere else, African populations are known to harbor the greatest genetic diversity in the world. Biodiversity can include everything from towering redwood trees to tiny, single-cell algae that are impossible to see without a microscope. It was this small portion that produced Rotimi's groundbreaking research. Wheat is one of the world's crucial staple food crops. There are 22 official languages and hundreds of dialects in the country (Annamalai, 2006), which reflect the genetic diversity of the population. Biodiversity refers to all the different kinds of living organisms within a given area. About 125 million peopleroughly 10% of the populationnow speak the English language ( Mehtabul et al., 2013 ), and members of many ethnic groups have migrated to other countries throughout the .
world: pampas in South America, v eldt in South . While European and Asian ancestral groups became distinct in the genetic record around 42,000 years ago, the researchers say that occurred even earlierapproximately 58,000 years agoin the case of. The typical scientifically curious intelligent person is generally aware that on the order of 100,000 years ago there was a movement of anatomically modern humans from Africa. Bottlenecks and founder effects.
The greatest genetic diversity of HIV-1 has been found in Africa especially in West Central Africa ; however, other parts of the continent show an assortment of diverse viral strains. availability of high genetic diversity which enabled to develop cultivars resistant to the disease in a very short time using materials from the wild coffee gene pool (Mesfin and Bayetta 1984). Rhinos typically live solitary lives and exist at low population . . Science. From this study, we showed that appreciable genetic diversity was present in on-farm and field genebank collections of cacao that can be exploited for crop improvement in West Africa. The researchers also discovered that one gene variant, which is found in 22 per cent of Africans, is associated with a change in levels of glycated haemoglobin in the blood, which is a measure used. Species diversity in a forest ecosystem depends on the genetic diversity of key tree species. Cultivated T. monococcum subsp. A locked padlock) or https:// means you've safely connected to the .gov website. Guinean forests of W est Africa 1,265,000 9,000 2,250 . The African Genome Variation Project analysed the DNA of 1,800 people living across the continent. Conservationists should be wary of assuming that genetic diversity loss in wildlife is always caused by humans, as new research published today by international conservation charity ZSL (Zoological Society of London) reveals that, in the case of a population of southern African lions (Panthera leo), it's likely caused by ecological rather than human factors. Most of these appear to have existed in the human gene pool at the time of the great human diasporas, including the migrations out of Africa. Nigeria alone boasts 500 unique ethnic groups whose .
Share sensitive information only on official, secure websites. The researchers explain that the long-term low genetic diversity could be, at least in part, due to rhino life history traits. That said, Europeans do have much of the phenotypic diversity. Like a fish in water, we've all been engulfed by "the smog" of thinking that "race" is . While the intermediate level of genetic diversity prevalent among the Asian and European populations has been conducive for development, the high degree of diversity among African populations and the low degree of diversity among Native American populations have been a detrimental force in the development of these regions. (2018), who reported mean genetic diversity of 0.38 and gene flow of 1.12 for 75 Z. tritici . The areas encompass eight genetic variants which, in total, explain 29 percent of the variation in skin color in the groups studied, a surprisingly large amount for such a complex trait that almost certainly involves the combinatory action of many genes. The high level of genetic diversity in African populations is also consistent with a larger long-term effective population size ( Ne) compared to non-Africans ( 72, 195, 196, 202, 206; Ne is estimated to be ~15,000 for Africans and ~7500 for non-Africans based on a resequencing analysis of several 10-kb regions ( 243) (see Supplemental Material ). The Ethiopian Center of Crop . On 2/11/19 at 5:00 AM EST. "Africa, which is the homeland of all modern humans, contains more than 2,000 ethnolinguistic groups and harbors great genetic and phenotypic diversity; however, little is known about fine-scale. 1. Genetic variation and susceptibility to disease are shaped by human demographic history and adaptation. Building the hypothesis In all of these events there was a significant genetic bottleneck for those leaving the continent. African populations are largely underrepresented in genetic research, but they face an elevated burden of disease.
Population bottlenecks occur when a population's size is reduced for at least one generation. Thus, genomic studies of diverse African ethnic groups are essential for understanding human evolutionary history and how this leads to differential disease risk in all humans.
Whites do not have the most genetic diversity of the different populational groups. Africa is rich in genetic diversity for many traits; and, in fact, human skin pigmentation is far more diverse across African populations than anywhere else in the world. The genetic diversity of cowpea was analyzed, and the population structure was estimated in a diverse set of 768 cultivated cowpea genotypes from the USDA GRIN cowpea collection, originally collected from 56 countries.
In general, 5%-15% of genetic variation occurs between large groups living on different continents, with the remaining majority of the variation .
Phylogenetic analysis of these and other relevant viruses is shown in Fig. Sure, different human populations living in distinct places may statistically have different genetic traits such as sickle cell trait (discussed below) but such variation is about local populations (people in a specific region), not race. The study published in the journal PLoS Genetics suggests that genomics can provide a valuable new tool for use in chimpanzee conservation. There have been a few major out-of-Africa events. Africans have more genetic variation than anyone else on Earth, according to a new study that helps narrow the location where humans first evolved, probably near the South Africa-Namibia border.. Coffee is known to be one of the most . Plus, groups intermingled so much over the course of history that genetic diversity is a continuum both within American and Europe, through to Asia and Africa, Novembre of the University of . These groups each share a common ancestor and can be one way of looking at the genetic makeup of a population. | http://radsaferaleigh.com/itouchwearables/calamansi/value/748175071e64d327c07e8db2bf3248-genetic-diversity-in-africa-vs-world |
Evolution is a very interesting concept in anthropology. It refers to the biological populations’ alteration of the inherited characteristics over successive generations. The processes in evolution bring diversity at each biological organization level including, individual organisms, molecules like proteins and DNA, and species. According to what we know, life on this universe actually originated and afterwards evolved from universal common ancestor. Perhaps this is what makes the subject of evolution appear more interesting since through it we get well informed about where we originated from and about our evolution.
The concept of evolution is basically categorized under both micro and macroevolution processes. Microevolution refers to changes in the allele frequencies which occur overtime within a given population. For that reason, microevolution refers to the smaller evolutionary changes. For that reason, microevolution is gene pool changes of a population over a certain period of time that result in fairly small changes to organisms found in the population. A good example of such changes includes species’ size or coloring change. This change is essentially as a result of the four processes which in this case are mutation, gene flow, genetic drift, and selection both artificial and natural.
Mutation is actually a nucleotide sequence change of an organism genome, extra chromosomal genetic element, or virus. These processes come as a result of unrepaired damage to the RNA genomes or to DNA, the deletion or insertion of DNA segments by the mobile genetic elements, or from the errors that result from replication process. Mutations therefore play an imperative role in both abnormal and normal biological processes.
Natural selection is a process whereby the traits that characterizes a certain population can essentially change overtime when the individuals in it vary in heritable traits, which are accountable for differences in reproduction and survival. Gene flow is changes in the allele frequency which result from individual migration between populations. In the absence of this process, the populations can be genetically distinct by genetic drift from one another. Genetic drift is a genetic variation among the allele frequencies as a result of random chance in a population. The alleles that are in the population offspring are actually a random sample of those that the parents have. In this gene drift, chance determines whether an individual reproduces or survives. The allele frequency in a population refers to the percentage or fraction of the population gene copies as compared to the whole number of gene alleles which share a certain form.
On the other hand, macroevolution is the evolution on a scale of gene pools that are separated. The focus of macroevolution is on the change which occurs above or at the species level. In this type of evolution the newer organisms are considered as entirely new species, which are unable to mate with the ancestors. The speciation process may in essence fall within the purview of both, depending on forces that are thought to drive it. The evolutionary biology, paleontology, genomic phylostratigraphy, and comparative genomics contribute the most evidence for the processes and patterns, which can be classified as Macroevolution. A good example of this phenomenon is feathers appearance during birth evolution from theropod dinosaurs.
Genetic variation is a phenomenon that is related to microevolution. It is in reality variation in genes alleles that occur both among and within populations. It is important since it provides the natural selection genetic material. Isolating mechanisms is another concept that is vital in evolution. These are features of morphology, genetics, or behavior that serve to stop breeding between the species. Reproductive isolation of the populations is therefore established. Particularly it is crucial to the concept of biological species since species are essentially defined by the reproduction isolation. | https://www.wowessays.com/free-samples/essay-on-garbology/ |
Background: Phylogeography is an important tool that can be used to reveal cryptic biodiversity and to better understand the processes that promote lineage diversification. We studied the phylogeographic history of the Arboreal Salamander (Aneides lugubris), a wide-ranging species endemic to the California floristic province. We used multi-locus data to reconstruct the evolutionary history of A. lugubris and to discover the geographic location of major genetic breaks within the species. We also used species distribution modeling and comparative phylogeography to better understand the environmental factors that have shaped the genetic history of A. lugubris.
Results: We found six major mitochondrial clades in A. lugubris. Nuclear loci supported the existence of at least three genetically distinct groups, corresponding to populations north of the San Francisco Bay and in the Sierra Nevada, in the Santa Cruz Mountains, and in the central coast and southern California. All of the genetic breaks in mitochondrial and nuclear loci corresponded to regions where historical barriers to dispersal have been observed in other species. Geologic or water barriers likely were the most important factors restricting gene flow among clades. Climatic unsuitability during glacial maximum may have contributed to the isolation of the mitochondrial clades in the central coast and southern California. A projection of our species distribution model to a future scenario with a moderate amount of climate change suggests that most of the range of A. lugubris will remain climatically suitable, but climatic conditions in the Sierra Nevada and low elevation areas in Southern California are likely to deteriorate.
Conclusions: Aneides lugubris contains substantial cryptic genetic diversity as a result of historical isolation of populations. At least two (and perhaps three) evolutionarily significant units in A. lugubris merit protection; all six mitochondrial clades should be considered as management units within the species.
An overview of the herpetological program of the Museum of Vertebrate Zoology (MVZ), University of California, Berkeley, is presented. The history of herpetological activities in the MVZ and more generally at Berkeley is summarized. Although the MVZ has existed since 1908, until 1945 there was no formal curator for the collection of amphibians and nonavian reptiles. Since that time Robert C. Stebbins, David B. Wake, Harry W. Greene, Javier A. Rodríguez-Robles (in an interim capacity), and Craig Moritz have served in that position. All type specimens of recent amphibians and nonavian reptiles in the collection are listed. The 1,765 type specimens in the MVZ comprise 120 holotypes, three neotypes, three syntypes, and 1,639 paratopotypes and paratypes; 83 of the holotypes were originally described as full species. Of the 196 amphibian and nonavian reptilian taxa represented by type material, most were collected in México (63) and California (USA, 54). Information is also provided concerning the collection. The first entry in the herpetological catalog in the MVZ was made on March 13, 1909 (MVZ 1, Crotaphytus bicinctores), and as of December 31, 2001, the collection contained 232,254 specimens of amphibians and nonavian reptiles. Taxonomically, the collection is strongest in salamanders, accounting for 99,176 specimens, followed by "lizards" (squamate reptiles other than snakes and amphisbaenians) (63,439), frogs (40,563), snakes (24,937), turtles (2,643), caecilians (979), amphisbaenians (451), crocodilians (63), and tuataras (3). A list, exclusive of abstracts and book reviews, of more than 1,300 articles, book chapters, and books on any aspect of the biology of amphibians published by researchers associated with the MVZ since its founding is available online at http://www.mip.berkeley.edu/mvz/collections/MVZHerpPubs.htm
The largest genus of salamanders, Bolitoglossa (Plethodontidae), is widespread in tropical America, where it occurs in diverse habitats and elevations, from high elevation grasslands to lowland rain forest. It has the most extensive geographical range of any salamander genus. While most species occur in Middle America, it ranges throughout most of tropical South America as well. Phylogenetic analysis of 1196 bp of two mitochondrial genes (cytochrome b, 16S RNA) from 55 species offers strong support for the monophyly of the genus and sorts the species into a number of clades. Taking into account morphology, distribution, general ecology, and prior systematic and taxonomic studies, we recognize seven subgenera, four of them new: Bolitoglossa Dumeril, Bibron et Dumeril, 1854, Eladinea Miranda Ribeiro, 1937, Magnadigita Taylor, 1944, Mayamandra, Nanotriton, Oaxakia and Pachymandra. All South American and some lower Middle American species are included in a single well supported clade, Eladinea. At the species level our analyses uncover the existence of large genetic diversity within morphologically homogeneous taxa. We propose the new combination: B. (Eladinea) paraensis (Unterstein, 1930) stat. nov., for Brazilian salamanders previously included under B. altamazonica. We evaluate evidence for the multiple colonization of the tropical lowlands by morphologically derived species groups. South America was invaded by members of one clade, Eladinea, which we infer to have dispersed to South America prior to closure of the Panamanian Portal. Despite the relatively long history of salamanders in South America, that continent now accounts for a relatively small proportion of the lineages and species of neotropical salamanders. (C) 2004 The Linnean Society of London,
Reproductive isolation (RI) is widely accepted as an important "check point" in the diversification process, since it defines irreversible evolutionary trajectories. Much less consensus exists about the processes that might drive RI. Here, we employ a formal quantitative analysis of genetic interactions at several stages of divergence within the ring species complex Ensatina eschscholtzii in order to assess the relative contribution of genetic and ecological divergence for the development of RI.
Results:
By augmenting previous genetic datasets and adding new ecological data, we quantify levels of genetic and ecological divergence between populations and test how they correlate with a restriction of genetic admixture upon secondary contact. Our results indicate that the isolated effect of ecological divergence between parental populations does not result in reproductively isolated taxa, even when genetic transitions between parental taxa are narrow. Instead, processes associated with overall genetic divergence are the best predictors of reproductive isolation, and when parental taxa diverge in nuclear markers we observe a complete cessation of hybridization, even to sympatric occurrence of distinct evolutionary lineages. Although every parental population has diverged in mitochondrial DNA, its degree of divergence does not predict the extent of RI.
Conclusions:
These results show that in Ensatina, the evolutionary outcomes of ecological divergence differ from those of genetic divergence. While evident properties of taxa may emerge via ecological divergence, such as adaptation to local environment, RI is likely to be a byproduct of processes that contribute to overall genetic divergence, such as time in geographic isolation, rather than being a direct outcome of local adaptation.
The evolutionary history of the largest salamander family (Plethodontidae) is characterized by extreme morphological homoplasy. Analysis of the mechanisms generating such homoplasy requires an independent, molecular phylogeny. To this end, we sequenced 24 complete mitochondrial genomes (22 plethodontids and two outgroup taxa), added data for three species from GenBank, and performed partitioned and unpartitioned Bayesian, ML, and MP phylogenetic analyses. We explored four dataset partitioning strategies to account for evolutionary process heterogeneity among genes and codon positions, all of which yielded increased model likelihoods and decreased numbers of supported nodes in the topologies (PP > 0.95) relative to the unpartitioned analysis. Our phylogenetic analyses yielded congruent trees that contrast with the traditional morphology-based taxonomy; the monophyly of three out of four major groups is rejected. Reanalysis of current hypotheses in light of these new evolutionary relationships suggests that 1) a larval life history stage re-evolved from a direct-developing ancestor multiple times, 2) there is no phylogenetic support for the "Out of Appalachia" hypothesis of plethodontid origins, and 3) novel scenarios must be reconstructed for the convergent evolution of projectile tongues, reduction in toe number, and specialization for defensive tail loss. Some of these novel scenarios imply morphological transformation series that proceed in the opposite direction than was previously thought. In addition, they suggest surprising evolutionary lability in traits previously interpreted to be conservative.
The analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders Ensatina eschscholtzii xanthoptica and Ensatina eschscholtzii platensis hybridize in the Central Sierran foothills of California. We compared the genetic structure across two transects (southern and northern Calaveras Co.), one of which was re-sampled over 20 years, and examined diagnostic molecular markers (eight allozyme loci and mitochondrial DNA) and a diagnostic quantitative trait (color pattern). Key results across all studies were: i) cline centers for all markers were coincident and the zones were narrow, with width estimates of 730m to 2000m; ii) cline centers at the northern Calaveras transect were coincident between 1981 and 2001, demonstrating repeatability over 5 generations; iii) there are very few if any putative F1's, but a relatively high number of backcrossed individuals (57-86 percent) in the central portion of transects; iv) we found substantial linkage disequilibrium in all three studies and strong heterozygote deficit both in northern Calaveras, in 2001, and southern Calaveras. Both linkage disequilibrium and heterozygote deficit show maximum values near the center of the zones (R and Fis, approx. equal to 0.5). Using estimates of cline width and dispersal, we infer strong selection against hybrids (s* approx. equal to 46-75 percent). This is sufficient to promote accumulation of differences at loci that are neutral or under divergent selection, but would still allow for introgression of a daptive alleles. The evidence for strong, but incomplete isolation across this centrally located contact is consistent with theory suggesting a gradual increase in postzygotic incompatibility between allopatric populations subject to divergent selection and reinforces the value of Ensatina as a system for the study of divergence and speciation at multiple stages. | https://escholarship.org/search/?q=author%3A%22Wake%2C%20David%20B%22 |
How do new species form? One key process is by genetic divergence following geographical isolation – allopatric speciation. This can happen when different populations of a single species are separated, cease to have contact over time and no longer interbreed. This separation, divergence and formation of new species will often be attributed to changes in genetic makeup as a result of adaptation to different environments or ecosystems, or simply to accumulated genetic changes - genetic drift.
When it's difficult for individuals from the population to cross geographical barriers, it's possible to explain how isolation of populations occurs, and therefore why speciation has happened. An example would be the different but related species found on islands separated from the mainland, where a few individuals managed to cross the water barrier and form a new population that eventually became a distinct new species. Charles Darwin collected specimens of mockingbirds on the Galapagos, for example, that are related to mainland species but which have diverged from the parent population to become a separate species, living in a new and different environment.
In the sea, however, many animals have pelagic larvae – free-floating planktonic forms - that can be carried for many hundreds of kilometres in currents, even though the adults have limited mobility on the sea bed. This pelagic mobility means that closely related species from different places are potentially connected over distances of 1,000 km or more, so it is unclear how allopatric speciation is achieved – the populations appear to be capable of connection in geographical terms.
Zoology PhD student Martine Claremont, together with her Museum supervisors Drs Suzanne Williams and David Reid, and university supervisor Professor Tim Barraclough, sampled populations of the intertidal muricid gastropod genus Stramonita (a marine snail) throughout the Atlantic Ocean and used statistical analysis of DNA sequences to identify the number of distinct species, their distributions and relationships.
For species in which the larvae spend only a short time in the plankton, it is possible for populations to be clearly isolated geographically by currents, island chains or other factors such as the immense flow of fresh water flowing from the mouth of the Amazon. However, Stramonita spends 2-3 months as a planktonic larval form, theoretically permitting genetic contact across the entire ocean basin, which might lead to expectations that a single population would be found around the Atlantic.
Stramonita brasiliensis, the new species described in the work (E, Plymouth, Tobago, BMNH acc. no. 2341; F, holotype, Sao Paulo, Brazil, BMNH 20100324)
However, Martine and her supervisors found five distinct species in the Atlantic (one of which is described as new). They suggest that this speciation might be attributed in part to past changes or interruptions in ocean currents, preventing free circulation and isolating populations for sufficient time to enable speciation. Other factors that seem to be of importance are the ancient separation of the Caribbean and Gulf of Mexico and the development of ecological specialization.
Claremont, M., Williams, S.T., Barraclough, T.G., Reid, D.G. (2011) The geographic scale of speciation in a marine snail with high dispersal potential. Journal of Biogeography, 38: 1016–1032. | https://www.nhm.ac.uk/natureplus/blogs/science-news/2011/05/24/how-do-new-species-form-in-the-ocean.html |
Climatic oscillations in Antarctica caused a succession of expansion and reduction of the ice sheets covering the continental shelf of the Southern Ocean. For marine invertebrates, these successions are suspected to have driven allopatric speciation, endemism and the prevalence of cryptic species, leading to the so-called Antarctic ‘biodiversity pump’ hypothesis. Here we took advantage of the recent sampling effort influenced by the International Polar Year (2007-8) to test for the validity of this hypothesis for 1,797 samples of two recognized crinoid species: Promachocrinus kerguelensis and Florometra mawsoni. Species delimitation analysis identified seven phylogroups. As previously suggested, Promachocrinus kerguelensis forms a complex of six cryptic species. Conversely, despite the morphological differences, our results show that Florometra mawsoni is a lineage nested within Promachocrinus kerguelensis. It suggests that Florometra mawsoni and Promachocrinus kerguelensis belong to the same complex of species. Furthermore, this study indicates that over time and space the different sectors of the Southern Ocean show a remarkable rapid turn-over in term of phylogroups composition and also of genetic variants within phylogroups. We argue that strong “apparent” genetic drift causes this rapid genetic turn-over. Finally, we dated the last common ancestor of all phylogroups at less than 1,000 years, raising doubts on the relevance of the Antarctic “biodiversity pump” for this complex of species. This work is a first step towards a better understanding of how life is diversifying in the Southern Ocean.
Introduction
During the last decade following the last International Polar Year (2007-8) a huge effort has been made to better understand Antarctic marine ecosystems and one of the major outcomes has been the creation of a reference barcode database (BOLD) that reconciles morphologically recognized species with a unique COI fragment. This opened to a new era of discoveries that allowed reassess some of the main known characteristics of marine Antarctic ecosystems, including eurybathy, excess in brooding species, high rate of endemism, rapid diversification and cryptic speciation as a consequence of the biodiversity pump (Clarke & Crame, 1989). Recent biodiversity assessments using molecular tools have revealed an increasing number of cryptic species in teleost fishes as well as Echinodermata, Mollusca, Arthropoda, or Annelida (see (Cornils & Held, 2014; Griffiths, 2010; Rogers, 2007) for comprehensive reviews). Cryptic species have been shown to be homogeneously distributed among taxa and biogeographic regions (Pfenninger & Schwenk, 2007) and Antarctica may well be no exception.
The Southern Ocean is known to have undergone several glaciation events (Clarke & Crame, 1989; Clarke, Crame, Stromberg, & Barker, 1992; Thatje, Hillenbrand, Mackensen, & Larter, 2008). Massive ice sheet advance and retreat seem to have bulldozed the entire continental shelf several times during the last 25 Mya. These events are thought to be driven by Milankovitch cycles. These cycles may be among the strongest evolutionary forces that have shaped Antarctic terrestrial and marine biodiversity (Clarke et al., 1992; Thatje et al., 2008; Thatje, Hillenbrand, & Larter, 2005). Thatje et al. (2005; 2008) hypothesized that vicariant speciation could have occurred during the glacial periods on the Antarctic continental shelf, within multiple ice-free refugia like polynya. As lineages evolved independently during the glacial period, they accumulated genetic differences that lead to reproductive isolation and probably to the formation of cryptic species. During interglacial periods, barriers to gene flow may have been removed allowing for secondary contact between the vicarious lineages (Heimeier, Lavery, & Sewell, 2010; Thatje et al., 2005; 2008; Thornhill, Mahon, Norenburg, & Halanych, 2008). An alternative hypothesis is based on the idea that Antarctic continental shelf may be understood as a species flock generator (Eastman & McCune, 2000; Lecointre et al., 2013).
Here, we have analyzed COI sequences of 1,797 individuals of two crinoid species: Promachocrinus kerguelensis (Carpenter, 1888) and Florometra mawsoni (AH Clark, 1937), endemic to the Southern Ocean. These species represent the most abundant crinoid species in the Southern Ocean (Eléaume, Hemery, Roux, & Améziane, 2014; Speel & Dearborn, 1983). They are morphologically distinct (but see (Eléaume, 2006) for counter arguments) and genetically close (Hemery, Améziane, & Eléaume, 2013a). These species are thought to have a reproduction cycle that involves external fertilization that could result in a large dispersal potential. P. kerguelensis produces positively buoyant ovocytes that, after fertilization, may remain in the plankton for weeks or even months (McClintock & Pearse, 1987). Some adults of P. kerguelensis have also been observed swimming (Eléaume, unpublished observations), and some adults of F. mawsoni, though never observed swimming in situ, have shown this ability in tanks (Eléaume, unpublished observations).
During the last decade, numerous specimens of crinoids have been collected from all around Antarctica and sub-Antarctic islands. Over 3,000 specimens attributed to 45 species have been sampled (Eléaume et al., 2014). Species such as Promachocrinus kerguelensis and Florometra mawsoni are represented by a large number of well distributed specimens. Knowlton (1993; 2000) predicted for Southern Ocean organisms that an increase in sampling effort and the application of genetic tools, would reveal cryptic species. The analysis of P. kerguelensis COI barcode fragment suggested that this species may constitute such an example of a complex of unrecognized species. Wilson et al. (2007) identified six lineages in the Atlantic sector whereas Hemery et al. (2012) extending the analysis of Wilson to the entire Southern Ocean, identified seven lineages. As no obvious morphological character have been shown to distinguish between these lineages (Eléaume, 2006), they may represent true cryptic species. However, Hemery et al. (2012) using nuclear markers have shown that the six identified COI lineages may only represent three distinct entities. All of the six or seven lineages are circumpolar in distribution, sympatric and eurybathic but show various levels of connectivity that depend on the lineage and the geographical area.
Here we analyze the pooled COI datasets of P. kerguelensis and F. mawsoni of Wilson et al. (2007) and Hemery et al. (2012) using different approaches to separate different sources of genetic variation, i.e. differences due to diversification (clade), time (year collected), space (geographical origin of samples). We first analyze the phylogenetic relationships within P. kerguelensis sensu largo using different species delineation methods. We then measure the genetic turn-over, within each phylogroup sampled at a given location. Using a population genetics coalescent framework, we estimated an extraordinary small effective population size that corresponds to a mutation rate that is larger than previously reported before. We then discuss our results in the light of the climate history of the Southern Ocean.
Materials and methods
Sequences
We included 13 sequences of P. kerguelensis from Wilson et al. (2007), for which we had precise information about the place and the date of sampling. We have also included 1303 sequences of P. kerguelensis from Hemery et al. (2012) together with 479 sequences of F. mawsoni (Hemery et al., in preparation). A total of 1,797 COI sequences were used for this study. All specimens were collected between 1996 and 2010 in seven geographical regions that were described in Hemery et al. (Hemery et al., 2012): Kerguelen Plateau (KP), Davis Sea (DS), Terre Adélie (TA), Ross Sea (RS), Amundsen Sea (AS), West Antarctic Peninsula (WAP), East Weddell Sea (EWS). We however further split the Scotia Arc into Scotia Arc East (SAE) and Scotia Arc West (SAW) as there can be as much as 2,000 km between them. The counts of all sequences of all locations are reported in Table S1.
DNA extraction, PCR and sequencing
For this analysis, no additional sequences have been produced. For DNA extraction and PCR procedures see (Hemery et al., 2012; Wilson et al., 2007) and 2013. A total of 1797 554-bp sequences of the barcode region of cytochrome c oxidase subunit I (COI) were amplified using the Folmer et al. (1994) primers and other specific primers described in Hemery et al. (2012). All COI sequences from Hemery et al. (2012) have been made easily available through a data paper article (Hemery et al., 2013a).
Species delimitation
We used three independent species delimitation methods: Generalized Mixed Yule Coalescent (GYMC, (Pons et al., 2006)), Automatic Barcode Gap Discovery (ABGD, (Puillandre, Lambert, Brouillet, & Achaz, 2011)) and Poisson Tree Process (PTP, (Zhang, Kapli, Pavlidis, & Stamatakis, 2013)) to estimate the number of phylogroups in our sample. For all these methods, we used all the 199 unique haplotypes of the dataset to have legible results and a faster computation time. The phylogenetic tree used for PTP was constructed by Neighbor Joining method the BioNJ implementation (Gascuel, 1997) in Seaview software (Gouy, Guindon, & Gascuel, 2010) version 3.2. PTP analysis was conducted online (http://species.h-its.org/ptp/). The ultrametric tree needed for GYMC method was constructed using BEAST software (Bayesian Evolutionary Analysis Sampling Trees, (Drummond, Suchard, Xie, & Rambaut, 2012) version 1.7). GYMC analysis was conducted online (http://species.h-its.org/gmyc/). ABGD analysis was conducted online (http://wwwabi.snv.jussieu.fr/public/abgd/abgdweb.html).
Assessing the temporal structure within phylogroups
We characterized the temporal structures of our samples in pairwise comparisons using both fixation index FST as well as a non-parametric structure test based on K*s by Hudson et al. (1992). All p-values were estimated using permutations as described in Hudson et al. (1992). A web-interface for the latter can be found at http://wwwabi.snv.jussieu.fr/public/mpweb/.
Estimation of the mutation rate and the population effective size
As described by Fu (2001) one can use temporal data to estimate the mutation rate (μ). In summary, the method assumes that the population is sampled in at least two time points (say T1 and then later T2) with multiple sequences in T1. The expected average pairwise differences between sequences taken from the two time points (K12) equals the average pairwise differences of sequences within the past time point (K11) plus the difference accumulated since then. Mathematically, it is expressed as E[K12] = E[K11] + (T2−T1)μ. Because the time difference between the samples (T2−T1) is known, the mutation rate can be estimated from the observed pairwise differences: μ = (K12−K11)/(T2−T1). This idea can be expanded when more data are available in other time points (Fu, 2001).
Once μ is known, the average pairwise difference can be used to estimate the effective population size (Ne). Under the standard neutral model, the pairwise difference within groups of the same sample equals 2Neμ, when μ is expressed as a rate by generations. Here, we assumed one generation every three year to estimate Ne (Clark, 1921).
Estimation of the time of divergence between phylogroups
For visualization purposes, an ultrametric tree was constructed with the unique sequences by UPMGA (Michener & Sokal, 1957) as implemented in the Phylip package (Felsenstein, 1989) version 3.6. Using the estimated mutation rate, we derived a time of divergence within and between phylogroups from the average sequence differences.
Polymorphisms analysis
We used Dnasp software version 5.10 (Librado & Rozas, 2009) and the program used to study genetic structure to study the SFS (Site Frequency Spectrum) within phylogroups as well as two of its summary statistics: nucleotide diversity (π) and number of polymorphic sites (S). We then tested neutrality using Tajima’s D (Tajima, 1989), Fu and Li’s F* and D* (Fu & Li, 1993), Achaz’s Y* (Achaz, 2008), that is immune to sequencing errors, and the Strobeck (Strobeck, 1987) haplotype test.
Assessment of migration effect on Ne estimation through simulations
To assess the potential effect of migrants from a distant population on the estimation of μ and Ne, we used coalescent simulations where two samples of 20 sequences each are taken 3N generations apart in a focal population of size N. We assume a large unsampled ghost population of size 10N that exchange migrants with the focal one at rate M=4Nm, where m is the migration rate per generation. For values of M ranging from 0.001 (very low) to 1000 (very large), we applied the Fu (Fu, 2001) method to estimate Ne, with 103 replicates for each M value. The program is based on a C++ library developed by G. Achaz that is available upon request.
Results
P. kerguelensis and F. mawsoni are composed of seven phylogroups
We first reinvestigated the species delimitation of the sample using three independent approaches (GMYC, ABGD and PTP) that cluster the unique sequences by phylogroup. We adopt in this manuscript a nominalist definition of species. However, F. mawsoni, a nominal species, is nested within P. kerguelensis, another nominal species, lineages. To avoid confusion, we have decided to use the term “phylogroup” in the rest of the manuscript to designate any well-supported cluster of sequences derived from species delineation approaches.
Two of the three methods estimate a similar number of phylogroups: PTP estimates that there are nine phylogroups in the sample whereas ABGD reports 5-7 phylogroups, depending on the chosen prior value. Looking at the proposed partitions, we have chosen to consider seven different phylogroups for this study that are reported as phylogroups A-G in Fig. 1. Interestingly, these phylogroups correspond to the A-F groups proposed by Wilson et al. (2007), plus a ‘new’ group (G) that corresponds to the F. mawsoni species. The two extra sub-splits suggested by the PTP method are indicated as C1/C2 and E1/E2 on Fig. 1. Note that PTP only seeks monophyletic groups and thus must split the C group into the C1/C2 subgroups.
In contrast with the two previous methods, depending on the sequence evolution model we used and the BEAST parameters, GMYC reports between 3 and 51 phylogroups with non-overlapping grouping between individuals. As GMYC is very sensitive in our case to the chosen parameters, it is here unreliable and we chose to not consider the GMYC partitions.
Genetic distance between phylogroups are similar to the distance of each phylogroup to the G group. However, G group corresponds to a nominal species (F. mawsoni) which suggests that the A-G phylogroups could correspond to seven different yet undescribed species.
A very rapid local turn-over
Relative abundance of phylogroups
Two of the analyzed locations (Ross Sea and East Weddell Sea) were densely sampled (at least 50 sequences) at two (or more) different time points. We therefore took advantage of these time series to evaluate the turnover of the resident crinoids from year to year. The analysis of the relative abundance of the various phylogroups shows that for both locations the genetic composition is highly unstable through time (Fig. 2a and 2c). Phylogroup composition in EWS is stable from 1996 to 2004, and changes drastically in 2005 when phylogroup C has not been sampled. This pattern leads to a highly significant difference between all years (Fisher exact test, P = 4.7 10−10). Similarly, the composition of the RS location is also highly significantly different between 2004 and 2008 (Fisher exact test, P = 3.2 10−11); in this case, phylogroup A is replaced by phylogroups B and E.
Other locations display a single sampling event (AS, DS, TA) or reduced number of sequences over several sampling events (e.g. SAW: 2 sequences in 2000, 11 in 2002, 7 in 2006 and 68 in 2009), and cannot be used to robustly assess the stability of phylogroup relative abundance.
Turn-over within the phylogroups
We then measured the replacement of genetic variants within the phylogroups. To do so, we considered samples with at least 10 sequences of the same phylogroup in the same location at two different time points. The pairwise comparisons for such groups are all reported in Table 1 and we provide two graphical representations for phylogroup D in the RS location (Fig. 2b) and phylogroup C in the EWS location (Fig. 2d). In two cases (phylogroup C in EWS and phylogroup D in RS), we found a significant difference in the genetic composition within each phylogroups even when they are separated by only few years, again suggesting an unexpectedly high turn-over of the genetic pool of these crinoids. Interestingly, the temporal differentiation of phylogroup E within EWS is already FST=4% in four years, that is not significant because of the small sample size (10 and 11 respectively). Only the two samples of phylogroup G in EWS, that are separated by a single year, show no sign of temporal differentiation (FST=1%).
Estimation of the mutation rate and the effective population size
Using the robust yet elegant approach devised by Fu (2001), we estimated the yearly mutation rates (μ) from the same sample comparisons (i.e. phylogroups with two or more samples of 10 or more sequences within the same location). Furthermore, we also estimated the corresponding effective population size (Ne) assuming a generation time of three years. Results (Table 2) shows that all estimated mutation rates are 10−5-10−4 /bp/year, with a mean of 8.10−5 /bp/year. Results also show that the effective sizes are very low, on the order of 2-7 (Table 2). The very low effective size corresponds to the unexpected high turn-over of the genetic pool that we observe within the phylogroup at the same location.
Polymorphism analysis
For samples of 10 sequences or more (with the same year and same location), we have analyzed the characteristics of segregating polymorphisms using four neutrality tests: Tajima’s D (Tajima, 1989), Fu and Li’s F* and D* (Fu & Li, 1993), Achaz’s Y* (Achaz, 2008) and Strobeck P-values (Strobeck, 1987). Results (Fig. 3) show almost no deviation from the standard neutral model, except for the Fu and Li’s F* and D*. This statistics points to a clear excess of singletons. However, singletons likely contain sequencing errors that strongly skew these statistics (Achaz, 2008). The Y statistics that ignores singletons exhibits a distribution that is very close to the one expected under the standard neutral model. We therefore conclude that the observed polymorphisms suggest that basic assumptions of the standard neutral model (i.e. constant population size, no migration, no structure and no selection) cannot be rejected for these crinoid phylogroups.
Assessing the effect of migration using simulations
To test whether migration could accelerate the genetic turn-over of a species on a given location, we studied a simple model where the sampled location exchanges migrants with a large pool of panmictic individuals. One expects that a constant arrival of migrants from this large pool could interfere with the estimation of effective size. We thus simulated a model where the sampled population has a size N and the pool 10N. We studied the impact of the migration rate on the estimation of Ne using the same method than above (2001). Results (Fig. 4) show that at low migration rate, the estimator is unaffected whereas it is inflated up to 11N at high migration rate. This shows that the existence of a large pool from where migrants can come into the sampled population can only inflate the estimation of Ne and therefore cannot explain the low Ne we have estimated.
Phylogroups divergence
We then computed an estimate for the times of split between the seven phylogroups using our population genetics estimation of the mutation rate (8.10−5 mutations /bp /year). Our estimates are reported in an ultrametric tree (Fig. 5) where the oldest split between the phylogroups is estimated around 400 years. This very short time scale is in sharp contrast with the millions of years of previous estimations based on other estimated mutation rates (3.10−8 mutations /bp /year) that were based on echinoderms thought to be separated by the formation of the panama isthmus (Lessios, Kessing, Robertson, & Paulay, 1999).
Discussion
Speciation in Antarctica: the classical view
Due to its extreme environmental conditions, it has been hypothesized that climate driven evolution in Southern Ocean has been more important than in other ecosystems where ecological interactions play a larger role (Rogers, 2012). The diversity and the distribution of many marine taxa in Antarctica has been strongly shaped by climate variation and continental drift leading to dispersal, vicariance and extinction since the break-up of Gondwana (Williams, Reid, & Littlewood, 2003). Indeed, the global climate change at the end of the Eocene related to the continental drift is characteristic of the transition from a temperate climate to the current polar climate in Antarctica (Clarke et al., 1992; Clarke & Crame, 1989). The physical separation of Antarctica, South America and Australia resulted in the cooling of the Southern Ocean, which in turn initiated the physical and climate isolation of this region of the world (Tripati, Backman, Elderfield, & Ferretti, 2005). This isolation was followed by an extensive continental glaciations and the initiation of the Antarctic Circumpolar Current in the Miocene (Clarke et al., 1992; Clarke & Crame, 1989; Thatje et al., 2008). These two processes exacerbated the environmental and biological isolation of the Southern Ocean and are classically recognized as the main explanation to the high level of endemism observed in Antarctica (Clarke & Crame, 1989; Griffiths, Barnes, & Linse, 2009).
The Quaternary was marked by the oscillation of glaciation and interglacial periods, which strongly affected the ice cover present in Antarctica (Davies, Hambrey, Smellie, Carrivick, & Glasser, 2012). These cycles led to severe temperature oscillations and to the succession of large extensions of the ice sheets on the continental shelf followed by retreats of the ice sheets. They have been one of the main drivers of the diversification of species in Antarctica. Indeed, the isolation of populations in ice free refugia during the glacial era, such as polynya or in the deep sea, has been suggested as a mechanism of fragmentation of populations leading to allopatric speciation in the Southern Ocean. This process is called the Antarctic ‘biodiversity pump’ (Clarke et al., 1992; Clarke & Crame, 1989). The Antarctic ‘biodiversity pump’ has been proposed to be the main mechanism driving speciation and diversification in Antarctica.
Our knowledge on evolutionary history of Antarctic fauna was classically derived from studies of the systematics and distribution of marine animals relying heavily on the morphology of present and past (fossil) organisms. Such approaches are limited for two main reasons. First, species morphology may not reflect the true evolutionary relationships between taxa (DeBiasse & Hellberg, 2015). Second, several periods of time lack a reliable fossil record. Today, the emergence of molecular approaches provides a powerful tool to circumvent these limitations. To this regard, the increasing number of phylogeographic studies allow to get a better understanding of the effects of past changes on the current diversity and spatial distribution of organisms (Allcock & Strugnell, 2012). They also allow to accurately assess the distribution of genetic diversity within and among species. Such information is extremely valuable to evaluate and mitigate the impacts of human-induced activities on the biodiversity of the Southern Ocean (Chown et al., 2015). This study take place in this context and by expanding the results of two previous studies (Hemery et al., 2012; Wilson et al., 2007), we aimed to determine the drivers of the diversity of two crinoid taxa in the Southern Ocean, P. kerguelensis and F. mawsoni.
The concept of species: is Promachocrinus kerguelensis a complex of multiple cryptic species?
The analysis of 1797 sequences using recent species delimitation approaches allowed to identify seven operational taxonomic units. We confirmed the presence of six phylogroups (A-F) identified in two previous study (Hemery et al., 2012; Wilson et al., 2007), but only the PTP method supports the further split between E1 and E2 suggested by Hemery et al. (2012). Furthermore, despite their strong morphological differences and monophyly (Fig. 1), our results strongly suggest that F. mawsoni (phylogroup G) belongs to the P. kerguelensis complex. Indeed, the reciprocal monophyly of G and F and the proximity of E to G/F compare to A-D confirm the affiliation of G as a member of P. kerguelensis complex (Fig. 1). Therefore, we corroborated Hemery et al. (2012) results showing that P. kerguelensis consists in a complex of several cryptic species. We also confirmed Eléaume (2006) conclusion that despite striking exterior morphological differences phylogroup G is also a member of this complex of species, and Hemery et al. (2013b) results based on a multi-markers phylogenetic reconstruction.
Morphological similarities between cryptic species often reflect a recent speciation event (Bickford et al., 2007). In the marine realm, speciation is less associated to morphology than to other phenotypic aspects such as chemical recognition systems (Palumbi, 1994). Knowlton (1993) argued that marine habitats are likely to be filled with cryptic species although rarely recognized due to limited access to marine habitats. Molecular approaches can be particularly powerful in detecting cryptic species on the basis of their molecular divergence, and recent molecular studies helped reveal the prevalence of cryptic species (See for example (Brasier et al., 2016; Grant, Griffiths, Steinke, Wadley, & Linse, 2010)). This is particularly the case in the Southern Ocean where numerous molecular studies have suggested the presence of cryptic species (Baird, Miller, & Stark, 2011; Brasier et al., 2016; Grant et al., 2010; Wilson, Schrödl, & Halanych, 2009) with areas such as the Scotia Arc representing potential hotspots of cryptic diversity (Linse, Cope, Lörz, & Sands, 2007). The prevalence of invertebrate cryptic species in the Southern Ocean is probably due to the cyclical variation of ice sheets extent in Antarctica during repeated glacial and interglacial periods which could have fostered the separation of population, promoting genetic divergence and allopatric cryptic speciation (Clarke & Crame, 1989). During glacial periods, ice sheets extension is thought to have forced marine species inhabiting the continental shelf to take refuge in the deep sea or in shelf refugia, such as areas where permanent polynyas (Thatje et al., 2008) occurred. During glacial maxima the decrease of gene flow between populations would have promoted reproductive isolation and increased genetic variation between populations. Under glacial maximum extreme environmental conditions, a potential increase of the diverging selective pressures on behavioral and physiological characters rather than morphology (which could be under strong stabilizing selection), could lead to a reduction of the morphological changes usually associated with speciation (Fišer, Robinson, & Malard, 2018). In such a scenario, high levels of divergence are expected on neutrally evolving genes as observed in this study. This process might explain the high number of cryptic species reported in the Southern Ocean.
The concept of species is controversial in biology as there is no unique definition that can be applied to all species under all circumstances (Mayden, 1997). Here, the application of species delimitation methods (based on the genetic concept of species) using molecular tools identified six highly divergent lineages indiscernible on the basis of their morphology and a last morphologically divergent lineage. Therefore, this study show how the use of molecular data can provide new insights into the nature of the genetic boundaries between species (Pante et al., 2015). However, in the light of these findings we can wonder what do the lineages highlighted in this study represent? Are they genuine different species? Here the use of different criteria to delineate species based on reproductive isolation (biological concepts of species) or on morphology (morphological concept of species) will probably lead to the identification of a different number of species (Fišer et al., 2018). This is a good illustration of the “species problem” and stress out the fact that the notion of species itself is an abstract concept that should be questioned (De Queiroz, 2007). It has also important consequences in term of the protection of the biodiversity because disparate groupings of species will in turn result in different economic implications and conservation decisions (Frankham et al., 2012).
A remarkably fast turn over and low effective population sizes
This study indicates that over time the different sectors of the Southern Ocean show a remarkable turn over in term of phylogroup composition. For example, in less than a decade, the Ross and East Weddell Sea phylogroups composition changed substantially (Fig 2a and 2c). A, B and F may or may not be sampled from one year to the next, whereas C, D and G are always present but their proportions change drastically (Fig 2a and 2c). This observation suggests that within the same geographical region, the real number of individual per phylogroup varies considerably over time. One hypothesis that could explain these patterns is the presence of strong marine currents (such as the ACC, Ross Gyre and Weddell Gyre) mixing individuals and thus changing continuously their distribution across the Southern Ocean over time. A similar mechanism has been evoked to explain the current diversity and the distribution of sponges across the Southern Ocean (Downey, Griffiths, Linse, & Janussen, 2012).
Furthermore, within phylogroups, in a few years, the genetic makeup can change significantly. For instance, the genetic composition of the phylogroup C and D changed totally between 1996 and 2008, respectively in the East Weddell Sea and Ross Sea (Fig. 2b, d). Such spatio-temporal variations in term of genetic composition could also be attributed to marine currents that constantly shuffle individuals between populations. Over time, the constant arrival of individuals stemming from different populations continually modify the observed genetic composition within the same geographical location.
Alternatively, a rapid divergence of the genetic pool by genetic drift, or any other population processes, could also explain this rapid genetic turn over. The low effective population sizes highlighted in this study (Ne < 10; Table 2) are also consistent with this pattern. Indeed, lower values of Ne are associated with increased amount of “apparent” genetic drift. Furthermore, isolated populations are expected to diverge inversely proportional to their effective population sizes. Therefore, when the effective population sizes are extremely low, populations can significantly diverge from each other in just a few generations (Hudson & Coyne, 2002).
The simulations conducted in this study (Fig. 4) show that gene flow from an unsampled reservoir should inflate the Ne values estimated with the method of Fu (Fu, 2001). Therefore, due to the extremely low value of Ne observed, the hypothesis of a rapid divergence by “apparent” genetic drift is favored here over the hypothesis of a rapid divergence mediated by marine current continually modifying the genetic pool of the populations.
It is also important to bear in mind that our estimates of Ne depend directly on the number of generations per year (Fu, 2001). In Table 2, we assumed a generation time of three year, however if for example we assumed a generation time of 30 years, our estimates of Ne would increase tenfold. In our case, depending on the assumed value of the generation time, the interpretation of the Ne could change accordingly.
Overall, the Ne values estimated in this study for the P. kerguelensis and F. mawsoni are low. However, they are highly abundant in the Southern Ocean (Hemery et al., 2013a; McClintock & Pearse, 1987) which is indicative of a high census size. Such a discrepancy between the census (Nc) and effective (Ne) population size is commonly observed in nature, especially for marine species with large size (Filatov, 2019). However, the reasons behind it are not always clear (Filatov, 2019; Palstra & Fraser, 2012). At least four biological phenomena could cause Nc and Ne to be different in P. kerguelensis complex (with Ne ≪ Nc). First, an unequal sex ratio, i.e. an uneven number of males and females contributing to the next generation, lead the rarer sex to have a greater effect on genetic drift which decreases Ne compare to Nc. Although this hypothesis is plausible, to this day the sex ratio of P. kerguelensis and F. mawsoni remains unknown. Furthermore, the sex-ratio distortion would need to be extreme to reach such a low Ne. Second, a fluctuation of Nc over time can affect the ratio between Ne and Nc. Indeed, an estimate of Ne over several generations is the harmonic mean of Nc over time. Therefore, if Nc changes substantially over time, Ne is typically smaller than Nc. Fig. 2 indicates that the proportion of P. kerguelensis and F. mawsoni lineages can vary radically from year to year and thus the fluctuation of Nc over time for each lineage can change consequently leading Ne to be smaller than Nc. Third, the reproductive strategy of P. kerguelensis and F. mawsoni can participate to reduce Ne compared to Nc. Indeed, when individuals contribute unequally to the progeny of the next generation, a great proportion of the next generation comes from a small number of individuals which reduces Ne. Due to its mode of reproduction, P. kerguelensis is particularly incline to have a very reduced number of individuals contributing disproportionately to the progeny. Reproduction occurs synchronously around the months of November and December where males and females spawn and due to the dispersion of gametes by currents, a very small proportion of individuals have their ovocytes fertilized (McClintock & Pearse, 1987). Therefore, only a very small part of the produced larvae contributes effectively to the gene pool. This phenomenon can drastically reduce Ne compare to Nc and has been reported in different spawning species (Lind, Evans, Knauer, Taylor, & Jerry, 2009). This mode of reproduction can also explain the spatio-temporal genetic turn over mentioned previously. Lastly, due to its haploid and uni-parental nature, the Ne of the mtDNA is known to be four times smaller than that of nuclear DNA. Moreover, this effect can be exacerbated by the action of natural selection. Indeed, natural selection can reduce Ne and the mtDNA is known to be under positive and negative selection (Meiklejohn, Montooth, & Rand, 2007). Positive natural selection, for example, is expected to reduce the genetic diversity leading to a low Ne (Gossmann, Woolfit, & Eyre-Walker, 2011). Indeed, recurrent selective sweeps, related to positive mutations, will reduce the genetic diversity by hitchhiking resulting in a lower Ne compared to Nc. In this regard, Piganeau & Eyre-Walker (2009) found a strong negative correlation between Ne and the strength of the natural selection operating on the mtDNA on non-synonymous mutations. In addition, the non-recombining nature of the mtDNA is expected to make this effect even stronger. There are accumulating evidences suggesting that positive natural selection is acting on echinoderm mitogenomes (Castellana, Vicario, & Saccone, 2011). For example, the strong bias of codon usage observed in the mtDNA of the crinoid species Florometra serratissima compared to many other echinoderms, is also in favor of the idea that some sort of natural selection is occurring, though the mechanism behind it is still not fully understood (Scouras & Smith, 2001).
Tempo of speciation: Promachocrinus kerguelensis challenges the biodiversity pump hypothesis
The mutation rate estimated in this study is approximatively equal to 10−5 mutations/site/year and is based on population genetics data. Previous estimate of the mutation rate based also on the COI applied to closely related species (Lessios et al., 1999) used a phylogeny based approach and yielded a mutation rate of roughly 3 order of magnitude lower (≈ 10−8 mutations/site/year). Such a discrepancy between mutation rates derived from population data and phylogeny has been already documented (Burridge, Craw, Fletcher, & Waters, 2008; Madrigal et al., 2012) and is called “time dependency of molecular rates” (Ho et al., 2011; Ho, Phillips, Cooper, & Drummond, 2005). For example, in human, the mitochondrial D-loop mutation rate derived from pedigree approaches produced an average value of 8.10−7 mutations/site/year whereas phylogenetic estimates yielded value of 2.10−8 mutations/site/year (Santos et al., 2005). Likewise, in fishes, Burridge (Burridge et al., 2008) observed a mutation rate of ≈10−7 using a population based approach and ≈10−8 mutations/site/year from a phylogenetic estimates. The potential causes of the “time scale dependency” are reviewed in Ho et al. (2011), but one of the main reason behind it is that population genetics based calibrations lead to estimates reflecting the spontaneous mutation rates, whereas phylogeny based calibrations reflect the substitution rates (i.e. fixed mutations). Therefore, because purifying selection remove the vast majority of the spontaneous deleterious mutations, which constitute a large proportion of them, the spontaneous mutation rate is higher than the substitution rate. Consequently, the rates of molecular evolution decrease with the age of the calibration used to estimate them and it is invalid to assume that a unique molecular clock applies over all time scales (Ho et al., 2005; 2011). A major implication of time dependency is that estimates of recent population divergence times will require re-estimation (Burridge et al., 2008). Therefore, many studies suggesting population isolation related to the Pleistocene glaciations might need to convert these time estimates to more recent ones (i.e. last glacial maximum or Holocene).
Furthermore, the large variation of the mutation rates across the mtDNA regions and between different lineages (Nabholz, Glemin, & Galtier, 2009), leads the mtDNA to strongly deviate from the molecular clock assumption, which is generally assumed in phylogenetic reconstruction. Therefore, estimates of mtDNA mutation rates relying on phylogenetic approach should be taken with caution (Nabholz et al., 2009; Nabholz, Glemin, & Galtier, 2008). Conversely, the mutation rate estimated in this study are quite robust as they are model-free ((Fu, 2001); See also Material and Methods). In the case of P. kerguelensis and F. mawsoni, the different mutation rates estimated have important consequences on the age of the separation of the different lineages (Fig. 4). Indeed, the estimate from Lessios et al. (1999) suggest that the split between the different lineages would have occurred in the last million year (Fig. 4), which is congruent with the hypothesis of the biodiversity pump suggesting that most of the speciation events would have occurred during the Quaternary cycles (Clarke et al., 1992; Clarke & Crame, 1989). Conversely, with our estimate the separation would have occurred in the last 1000 years, implying an extremely recent and rapid diversification for P. kerguelensis and F. mawsoni.
Explosive radiations have been reported for several taxa (Mahler, Ingram, Revell, & Losos, 2013; Moore & Robertson, 2014; Muschick, Indermaur, & Salzburger, 2012) and are, in general, associated with the Pleistocene glacial cycles (Hawlitschek et al., 2012). In contrast, using the molecular rate estimated in this study, in our case the diversification would have happened during the Holocene. Such a remarkably rapid diversification has been rarely recorded in nature (but see Muschick et al., 2012; Peccoud, Simon, McLaughlin, & Moran, 2009). Furthermore, most of rapid radiations reported so far are adaptive and associated to morphological novelties that allow taxa to exploit separate niches. Taxa involved in rapid diversification are generally ecologically/morphologically highly differentiated (Losos & Miles, 2002). Here, most of the lineages display no obvious morphological differences (except for Florometra) or niche differentiation. As a consequence, the radiation within the P. kerguelensis complex is probably mainly nonadaptive (Rundell & Price, 2009) or adaptive but related to characters that are challenging to distinguish/observe (physiology or behavior). In this context, it is worth noting that structural genomic changes could also drive taxa to rapid adaptive (Kirkpatrick & Barton, 2006) and nonadaptive (Rowe, Aplin, Baverstock, & Moritz, 2011; Rundell & Price, 2009) radiation and may represent the mechanism underlying the diversification of the P. kerguelensis complex.
Finally, the low effective population sizes estimated (Table 2) are congruent with the rapid diversification rate observed. Indeed, Hudson and Coyne (2002) showed that for mtDNA, under the isolation model, two lineages would take between 2 and 3Ne generations to become reciprocally monophyletic by lineage sorting. Therefore, using the low effective population size estimated in this study (Table 2), it would take a few hundreds of years for two isolated taxa to reach complete reciprocal monophyly. This result is concordant with the divergence observed in this study and contributes to invalidate the Antarctic “biodiversity pump” for the Promachocrinus complex.
Acknowledgments
The following persons deserve our special thanks for having collected, curated and made available specimens from all around Antarctica: Ty Hibberd (AAD, Hobart), Owen Anderson, David Bowden, Sadie Mills, Kareen Schnabel and Peter Smith (NIWA, Wellington), Stefano Schiaparelli (University of Genoa), Jens Bohn and Eva Lodde (ZSM, Munich), David Barnes, Katrin Linse and Chester Sands (BAS, Cambridge). Our thanks also go to crew and scientists on board various cruises: CEAMARC (IPY project 53), POKERII, TAN08 and AMLR2009 cruises. Funding parties also include three Actions Transversales du MNHN: “Biodiversité actuelle et fossile; crises, stress, restaurations et panchronisme: le message systématique”, “Taxonomie moléculaire: DNA Barcode et gestion durable des collections” and “Biominéralisation”; the French Polar Institute IPEV (travel grants to LGH and ME on REVOLTA); This work was supported by the Consortium National de Recherche en Génomique, and the Service de Systématique Moléculaire (SSM) at the MNHN (USM 2700). Part of the molecular work was also supported by collaboration between the Census of Antarctic Marine Life, the Marine Barcode of Life (MarBOL) project and the Canadian Centre for DNA Barcoding (CCDB). DS was supported by funding of the Alfred P. Sloan Foundation to MarBOL. Laboratory analyses on sequences generated at the CCDB were funded by the Government of Canada through Genome Canada and the Ontario Genomics Institute (2008-OGI-ICI-03). We also gratefully thank Lucile Perrier, Charlotte Tarin, Jose Ignacio Carvajal III Patterson (students) and Céline Bonillo (SSM) for their invaluable help in the molecular lab. This work was also funded by the University of Groningen through a PhD fellowship allocated to Yacine Ben Chehida. We also thank Michael C. Fontaine for the logistical support provided during the PhD of Yacine Ben Chehida. | https://www.biorxiv.org/content/10.1101/666248v3.full |
Presentation is loading. Please wait.
Published byTrever Dimsdale Modified about 1 year ago
1
Evolution of Populations
2
How Common is Genetic Variation Darwin’s theory of evolution by natural selection explained how life on Earth changed, or evolved, over many generations. What Darwin did not know was how heritable traits were passed down through each generation. The study of genetics helps scientists understand the relationship between inheritance and evolution. Genetics supports Darwin’s ideas. Scientists know that genes control traits and that many genes have at least two forms, or alleles. They also know that members of all species are heterozygous for many genes.
3
Variation and Gene Pools In genetic terms, evolution is any change in the relative frequency of alleles in a population. A population is a group of individuals of the same species that can interbreed. Members of a population share a gene pool. A gene pool is all the genes, and their alleles, in the population. The number of times that allele occurs in a gene pool compared to the number of times that other alleles for the same gene occur is the relative frequency of the allele.
4
Sample Population 48% heterozygous black 36% homozygous brown 16% homozygous black Frequency of Alleles allele for brown fur allele for black fur Relative Frequencies of Alleles
5
Sources of Genetic Variation The two main sources of genetic variation are mutations and gene shuffling. A mutation is any change in a sequence of DNA. Gene shuffling occurs during gamete formation. It can produce millions of different gene combinations. Both mutations and gene shuffling increase genetic variation by increasing the number of different genotypes (genetic makeup of an organism).
6
Single-Gene and Polygenic Traits The number of phenotypes (physical characteristics of an organisms) for a trait depends on how many genes control the trait. A single-trait is a trait controlled by only one gene. – If there are two alleles for the gene, two or three genotypes are possible. – An example in humans of a single-gene trait is the presence of a widow’s peak (a downward dip in the center of the hairline). The allele for a widow’s peak is dominant over the allele for a hairline with no peak. As a result, there are only two phenotypes – having a widow’s peak or not having one.
7
Frequency of Phenotype (%) 100 80 60 40 20 0 Widow’s peakNo widow’s peak Phenotype Phenotypes for Single-Gene Trait
8
Single-Gene and Polygenic Traits A polygenic trait is controlled by two or more genes. – Each gene of a polygenic trait may have more than one allele. – Polygenic traits form many phenotypes. – Variation in a polygenic trait in a population often forms a bell- shaped curve with most members near the middle. – An example of a polygenic trait is height in humans
9
Frequency of Phenotype Phenotype (height) Generic Bell Curve for Polygenic Trait
10
Natural Selection on Single-Gene Traits Evolution of populations results from the effects of natural selection on individuals. Natural selection on single-gene traits can lead to changes in allele frequencies and thus to evolution. The process can cause an increase or decrease in the relative frequency of an allele.
11
Natural Selection on Polygenic Traits Natural selection on polygenic traits is more complex. Natural selection on polygenic traits can occur in three ways. – Directional selection occurs when individuals at one end of the bell-shaped curve have higher fitness than individuals near the middle or the other end of the curve. Directional selection causes a shift in the curve toward the higher fitness end.
12
Directional Selection Food becomes scarce. Key Low mortality, high fitness High mortality, low fitness Graph of Directional Selection
13
Natural Selection on Polygenic Traits – Stabilizing selection occurs when individuals near the middle of the curve have higher fitness than those at either end. Stabilizing selection leads to a narrowing of the curve near the middle.
14
Key Percentage of Population Birth Weight Selection against both extremes keep curve narrow and in same place. Graph of Stabilizing Selection Low mortality, high fitness High mortality, low fitness Stabilizing Selection
15
Natural Selection on Polygenic Traits – Disruptive selection occurs when individuals at the upper and lower ends of the curve have higher fitness than those near the middle. Disruptive selection forms a curve with a peak at each end and a low point in the middle.
16
Disruptive Selection Largest and smallest seeds become more common. Number of Birds in Population Beak Size Population splits into two subgroups specializing in different seeds. Beak Size Graph of Disruptive Selection Number of Birds in Population Key Low mortality, high fitness High mortality, low fitness
17
Genetic Drift Natural selection is not the only source of evolutionary change. In small populations, chance can cause alleles to become more or less common. This kind of change in allele frequency is called genetic drift. Genetic drift occurs when individuals with a specific allele leave more descendants than other individuals, just by chance. Over time, this can cause an allele to become more or less common in a population.
18
Genetic Drift Genetic drift may also occur when a small group of individuals moves into a new habitat. By chance, the small group may have different relative allele frequencies than did the original population. When this happens, it is called the founder effect.
19
Sample of Original Population Founding Population A Founding Population B Descendants Genetic Drift
20
Evolution Versus Genetic Equilibrium To understand how evolution occurs, scientists first asked, “Under what conditions does evolution not occur?” The Hardy-Weinberg principle answers this questions. The principle states that allele frequencies in a population stay the same unless one or more factors change the frequencies. Genetic equilibrium is the condition in which allele frequencies remain constant.
21
Evolution Versus Genetic Equilibrium Five conditions are needed for a population to be in genetic equilibrium. 1. random mating 2. large population size 3. no migration 4. no mutations 5. no natural selection If all five conditions are met, relative allele frequencies will not change. Evolution will not occur.
22
Speciation Speciation is the formation of new species. For one species to evolve into two new species, the gene pools of two population must be separated.
23
Isolating Mechanisms As new species evolve, populations become reproductively isolated from one another. When members of two populations can no longer interbreed and produce fertile offspring, reproductive isolation has occurred. Reproductive isolation takes three forms. – Behavioral isolation occurs when populations have different courtship or reproductive behaviors. – Geographic isolation occurs when geographic barriers separate populations. Such barriers can include mountains or rivers. – Temporal isolation occurs when populations reproduce at different times.
24
Concept Map results from which include produced by which result in Reproductive Isolation Isolating mechanisms Behavioral isolationTemporal isolation Geographic isolation Behavioral differencesDifferent mating times Physical separation Independently evolving populations Formation of new species
25
Testing Natural Selection in Nature Peter and Rosemary Grant proved that natural selection is still causing finches on the Galapagos Islands to evolve. The Grants showed that there was enough heritable variation in finch beaks to provide raw material for natural selection. The couple also showed that beak differences led to fitness differences. These fitness differences have brought about directional selection.
26
Galapagos Island Finches
27
Speciation in Darwin’s Finches Combining the Grant’s and Darwin’s ideas, scientists have come up with a hypothetical scenario for the evolution of Galapagos finches. Speciation in the Galapagos finches occurred by – Founding of a new population: A few finches may have traveled from the mainland to one of the islands. There, they survived and reproduced. – Geographic isolation: Some birds then moved to a second island. The two populations were geographically isolated. They no longer shared a gene pool.
28
Speciation in Darwin’s Finches – Changes in the new population’s gene pool: Seed sizes on the second island favored birds with larger beaks. So this bird population evolved into a population with larger beaks. – Reproductive isolation: In time, the large-beaked birds were reproductively isolated from birds on other islands and evolved into a new species. – Ecological competition: If birds from the second island cross back to the first, they live in competition. Individuals that are most different from one another compete less and are most able to reproduce. In time, this may lead to the evolution of yet another species.
29
Studying Evolution Since Darwin Evolution continues today. For example, some bacteria are evolving resistance to certain drugs. Evolutionary theory can help us understand these changes.
Similar presentations
© 2017 SlidePlayer.com Inc.
All rights reserved. | http://slideplayer.com/slide/3798557/ |
Speciation outcomes from the progressive build up of mutations that reduce the possibility of mating between parental populations or decrease the fitness of hybridsthe so-called varieties obstacles. a comparative evaluation of genomic data from 61 pairs of populations/varieties of pets with variable degrees of divergence. Gene movement between diverging gene swimming pools is evaluated under an approximate Bayesian computation (ABC) platform. We show how the intermediate “gray area” of speciation, where taxonomy can be questionable frequently, spans from 0.5% to 2% of net synonymous divergence, regardless of varieties existence background ecology or qualities. Because of suitable modeling of among-locus variant in hereditary introgression and drift price, we clarify the position of nearly all ambiguous instances and uncover a genuine amount of cryptic species. Our evaluation also shows the high occurrence in pets of semi-isolated varieties (when some however, not all loci are influenced by obstacles to gene movement) and shows the intrinsic problems, both conceptual and statistical, of delineating varieties in the gray area of speciation. Writer 928134-65-0 manufacture Overview Isolated populations accumulate hereditary variations across their genomes because they diverge, whereas gene movement between populations counteracts divergence and will restore hereditary homogeneity. Speciation proceeds from the build up at particular loci of mutations that decrease the fitness of hybrids, 928134-65-0 manufacture avoiding gene flowthe so-called species barriers therefore. Importantly, varieties barriers are expected to act locally within the genome, leading to the prediction of a mosaic pattern of genetic differentiation between populations at intermediate levels of divergencethe genic view of speciation. At the same time, linked selection also contributes to speed up differentiation in low-recombining and gene-dense regions. We used a modelling approach that accounts for both sources of genomic heterogeneity and explored a wide continuum of genomic divergence made by 61 pairs of species/populations in animals. Our evaluation offers a unifying picture of the partnership between molecular capability and divergence to switch genes. We show how the “gray area” of speciationthe intermediate condition where varieties definition can be controversialspans from 0.5% to 2% of molecular divergence, with these thresholds being independent of species life history ecology and traits. Semi-isolated varieties, between which alleles could be exchanged at some however, not all loci, are several, with the initial varieties barriers being recognized at divergences only 0.075%. These total outcomes possess essential implications concerning taxonomy, conservation biology, as well as the administration of biodiversity. Intro An important concern in evolutionary biology can be focusing on how the continuous-time procedure for speciation can result in discrete entitiesspecies. There is normally no ambiguity about varieties delineation when distant lineages are compared. The continuous nature of the divergence process, however, causes endless debates about the species status of closely related lineages . A number of definitions of species have thus been introduced over the 20th century, each of them using its own criteriamorphological, ecological, phylogenetic, biological, evolutionary, or genotypic. A major problem is that distinct markers do not diverge with time at the same price . For example, in a few taxa, morphological variations evolve faster compared to the manifestation of crossbreed fitness depression, which establishes a long time before genome-wide reciprocal monophyly typically. In other organizations, morphology is nearly unchanged between lineages that display high degrees of molecular divergence . The erratic behavior and advancement of the many criteria is in a way that in an array of between-lineage divergencenamed the gray zone from the speciation continuumdistinct varieties concepts usually do not converge towards the same conclusions concerning varieties delineation . Besides taxonomic elements, the gray area offers elevated a rigorous controversy concerning the hereditary systems mixed up in development of varieties [5C7]. Of particular importance is the question of gene flow between diverging lineages. How isolated must two gene pools be for speciation to begin? How Rabbit polyclonal to OAT long does gene flow persist as lineages diverge? Is usually speciation a gradual process of gene flow interruption or a 928134-65-0 manufacture succession of periods of isolation and periods of contact? These questions are not only central in the speciation literature but also relevant to the debate about species delineation, with the ability of individuals to exchange genes being at the heart of the biological concept of species. As genomic data have become easier and less expensive to. | http://chloridechannels.com/speciation-outcomes-from-the-progressive-build-up-of-mutations-that-reduce/ |
As it goes through best writing services each one of these several environments, Listeria should acclimate as a means to continue on. Others may want to focus more exclusively on a particular category. This selection will improve the reproductive isolation.
It is a fact that mutations create lots of new variations, but this isn’t an illustration of Darwinian evolution. Therefore two individuals with exactly the same genotype can occasionally have different phenotypes in they live in various environments. Thus, it stays prevalent because heterozygous carriers are much more likely to survive to reproduction age as they are more likely to survive an onset of malaria.
What’s Truly Happening with Speciation Definition Biology
The capacity to reproduce in the wild suggests that they’re a single type of animal separated exclusively by their different fur color and other minor bodily characteristics that allow them to adapt to distinct ecosystems. For instance, say there’s a population of birds which are mostly blue, but some are red. When two species are observed in just the very same general area but not in the precise habitat, they may not own an opportunity to mate.
Scientists are always discovering new ways animals compete together. African leopards and South American jaguars would be an additional fantastic instance of two species of the very same type of animal geographically isolated from one another. Alongside the sum of http://cs.gmu.edu/~zduric/day/essay-help-edu.html space, some animals require a specific terrain, like the prairie dog.
The New Angle On Speciation Definition Biology Just Released
The BSC, same as different attempts to attain an extensive definition, has failed to turn into a universal principle. Baraminology was initially formulated to try to solve the issue of the large number of animals that would be on Noah’s Ark, but could also function as an excuse to accept speciation when it’s conclusively observed, while still rejecting evolution. This genetic change may be sufficiently substantial to result in a new species.
It should be mentioned that adaptation does affect, to some level, every species in a particular ecosystem. Evolution is a reality, it is a reality. Geographical isolation is just one of the best understood events and likely the most frequently experienced.
In reality, defining the term species in different cases is an active region of evolutionary biology. There’s a limit to the quantity of change a population can produce. Let’s look at the same example.
Thus the information which you choose to absorb will often reflect your present life values. It’s also known as the geographical isolation and is described above in this informative article. There are many differences Despite the way the expository essay may appear to be rather delight in the one which is persuasive.
The Upside to Speciation Definition Biology
In bacteria, the circumstance is quite different. It may be as simple as bringing in a glucose molecule. Genetic potential is the sum of variation a kind or kind of organism can produce from the genetic material that’s already present.
The geographical isolation is a kind of reproductive isolation. Adaptation is, to start with, a process, rather than a physical part of a body. Principal productivity examines the evapotranspiration rates of plants.
Mutations might be harmful or benign, but they could also be beneficial. Hybridization between two species sometimes results in a distinct phenotype. Parapatric speciation takes place when subpopulations of precisely the same species are largely isolated from one another, but have a narrow area where their ranges overlap.
To understand sympatric speciation, one has to first understand the other forms of speciation. It can be hard to distinguish from allopatric speciation. Allopatric speciation is readily the most typical form of speciation.
Sympatric speciation, on the flip side, occurs whenever the members of unique populations dwell in the very same area but speciation still occurs. The owl is an instance of incipient speciation. On account of the malleability of the period, and the simple fact that evolution causes gradual adjustments, we won’t ever see speciation (as creationists like to consider it, at least) happen.
The populations gotten paramountessays com so different that members of the various populations can’t breed with one another anymore if were they to be in the exact same habitat in the exact time. Possessing a wide variety of special species in an area is an indication of excellent biodiversity. Now think of different lineages to other regions of earth.
Animals are grouped into groups, and this classification is called taxonomy. It’s unique since it requires place while two subpopulations of the exact same species are occupying exactly the same selection or within a range that highly overlaps. Two subspecies have a tendency to dwell in two different geographical ranges, which might or might not overlap.
The Tried and True Method for Speciation Definition Biology in Step by Step Detail
The divergence of the 2 species will usually take place on a long duration of time, and it may be the effect of differences in things like diet, behavior and mate selection. In an identical style, some birds take lots of open sky to carry out their courtship flights. Within this way they can be changed during an extended time.
Mimicry is another type of coadaptation. Another definition online is from merriam-webster. Because of this, you might rest assured your term paper service will be delivered with a pro.
Chemical Biology is the extensive subject which addresses the method by which the chemistry can be applied to deal with the biological troubles. There are lots of marine biology colleges in the country and about the world for students to choose from. Many students in this area will decide to go on to graduate school. | https://eetrade.org/the-war-against-speciation-definition-biology/ |
Rubisco is characterised by its low affinity for its productive substrate, CO2 and slow catalytic turnover rate (i.e., 1-3 cycles per sec). Importantly, Rubisco reacts with O2 (photorespiration), and this culminates in loss of CO2 and energy. In C3 plants, photorespiration can drain more than 25% of fixed CO2 under non-stressful conditions. The ratio of photorespiration to photosynthesis increases with increasing temperature and decreasing intercellular CO2 such as occurs when stomatal conductance is reduced under water stress. C3 plants compensate for Rubisco’s inefficiencies by (i) opening their stomata to increase CO2 diffusion into chloroplasts, which increases water loss and lowers leaf-level water use efficiency, WUE; and (ii) investing up to 50% of leaf nitrogen in Rubisco, which lowers their leaf-level nitrogen use efficiency, NUE.
The C4 pathway supercharges photosynthesis and suppresses photorespiration by operating a CO2 concentrating mechanism which elevates CO2 around Rubisco. Although C4 photosynthesis incurs additional energy, the energy cost of photorespiration exceeds that of the CO2 concentrating mechanism above 25oC. Hence, higher radiation use efficiencies (i.e., efficiency of converting absorbed radiation into biomass) have been recorded for C4 than C3 crops. High bundle sheath CO2 concentration saturates C4 photosynthesis at relatively low intercellular CO2, allowing C4 plants to operate with lower stomatal conductance. Thus, leaf-level WUE is usually higher in C4 than C3 plants. Relative to C3 plants, Rubisco of C4 plants is faster (higher turnover rate) and operates under saturating CO2. Thus, C4 plants typically achieve higher photosynthetic rates with about 50% less Rubisco and less leaf nitrogen. Hence, photosynthetic NUE is higher in C4 than C3 plants. Accordingly, C4 plants are advantaged relative to C3 plants in hot and nitrogen-poor environments with short growing seasons, hence their great abundance in wet/dry tropics such as Northern Territory savannas.
As mentioned earlier, more than 50% of C4 plants are grasses. C4 grasses are confined to low latitudes and altitudes, whereas C3 species dominate at higher latitudes and altitudes. Generally, C4 species frequently occur in regions of strong irradiance. Ehleringer and colleagues (Ehleringer et al. 1997) proposed that these distribution patterns are best explained by the different responses of photosynthetic quantum yields to temperature between C3 and C4 plants.
C4 photosynthesis suppresses photorespiration by operating a CO2 concentrating mechanism that comes at additional energetic cost. This cost is independent of ambient CO2 and temperatures. In contrast, photorespiration (and its associated energy cost) increases steeply with temperature in C3 plants and is highly dependent on CO2 concentrations. Under saturating irradiance and current ambient atmospheric CO2 concentration, the threshold temperature where the cost of photorespiration in C3 plants exceeds that of the CO2 concentrating mechanism in C4 plants is estimated around 25oC. This model provides a physiological basis for understanding today’s contrasting geographic distribution between C3 and C4 grasses.
As an example, the C4 grasses of the northern Australian savannas are relatively un-shaded because of the low tree density and sparse canopy. Light is abundant and since the CO2 concentration inside C4 leaves is high, a potentially high rate of light-saturated assimilation can be exploited. Most C3 species reach light saturation in the range of one-eight to one-half full sunlight (Figure 2.7). In C4 species, canopy assimilation might not become light saturated even in full sunlight. C4 plants thus maintain a competitive advantage over C3 plants in tropical locations, where average daily light receipt is much larger than in temperate zones, and associated with warmer conditions that also favour C4 photosynthesis (Figure 2.6). Given strong sunlight, warmth and seasonally abundant water, biomass production by C4 plants is commonly double the rate for C3 plants. Typically, C3 plants produce 15–25 t ha–1 but C4 plants easily produce 35–45 t ha–1.
Physiological characteristics of the C4 subtypes
As outlined in previous sections, characteristic biochemical, anatomical and physiological traits are associated with each of the three “classical” C4 subtypes (Table 2.3). However, it should be noted that many C4 plants have leaf structures that fall outside the “classical” subtype division (eg, NADP-ME tribes, Arundinelleae and Neurachneae). As many as 11 anatomical-biochemical suites have been identified in C4 grasses. A curious aspect about the subtypes of C4 grasses is their biogeography. In Australia and elsewhere, NADP-ME grasses are more frequent at higher rainfall, NAD-ME grasses predominate at lower rainfall, while the distribution of PCK grasses is even across rainfall gradients (Hattersley 1992). | http://pia-dev.mgmt.science.uq.edu.au/content/225-environmental-physiology-c3-versus-c4-photosynthesis |
Warning:
more...
Generate a file for use with external citation management software.
Despite previous reports of no apparent photorespiration in C4 plants based on measurements of gas exchange under 2 versus 21% O2 at varying [CO2], photosynthesis in maize (Zea mays) shows a dual response to varying [O2]. The maximum rate of photosynthesis in maize is dependent on O2 (approximately 10%). This O2 dependence is not related to stomatal conductance, because measurements were made at constant intercellular CO2 concentration (Ci); it may be linked to respiration or pseudocyclic electron flow. At a given Ci, increasing [O2] above 10% inhibits both the rate of photosynthesis, measured under high light, and the maximum quantum yield, measured under limiting light ([phi]CO2). The dual effect of O2 is masked if measurements are made under only 2 versus 21% O2. The inhibition of both photosynthesis and [phi]CO2 by O2 (measured above 10% O2) with decreasing Ci increases in a very similar manner, characteristically of O2 inhibition due to photorespiration. There is a sharp increase in O2 inhibition when the Ci decreases below 50 [mu]bar of CO2. Also, increasing temperature, which favors photorespiration, causes a decrease in [phi]CO2 under limiting CO2 and 40% O2. By comparing the degree of inhibition of photosynthesis in maize with that in the C3 species wheat (Triticum aestivum) at varying Ci, the effectiveness of C4 photosynthesis in concentrating CO2 in the leaf was evaluated. Under high light, 30[deg]C, and atmospheric levels of CO2 (340 [mu]bar), where there is little inhibition of photosynthesis in maize by O2, the estimated level of CO2 around ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in the bundle sheath compartment was 900 [mu]bar, which is about 3 times higher than the value around Rubisco in mesophyll cells of wheat. A high [CO2] is maintained in the bundle sheath compartment in maize until Ci decreases below approximately 100 [mu]bar. The results from these gas exchange measurements indicate that photorespiration occurs in maize but that the rate is low unless the intercellular [CO2] is severely limited by stress.
National Center for
Biotechnology Information, | http://www.ncbi.nlm.nih.gov/pubmed/12231916 |
What is photosynthesis?
First Published
Photosynthesis is the process that releases the oxygen we breathe.
Photosynthesis is the process used by plants, algae and certain bacteria to turn sunlight, carbon dioxide (CO2) and water into food (sugars) and oxygen. Here's a look at the general principles of photosynthesis and related research to help develop clean fuels and sources of renewable energy.
Types of photosynthetic processes
There are two types of photosynthetic processes: oxygenic photosynthesis and anoxygenic photosynthesis. They both follow very similar principles, but oxygenic photosynthesis is the most common and is seen in plants, algae and cyanobacteria.
During oxygenic photosynthesis, light energy transfers electrons from water (H2O) taken up by plant roots to CO2 to produce carbohydrates. In this transfer, the CO2 is "reduced," or receives electrons, and the water is "oxidized," or loses electrons. Oxygen is produced along with carbohydrates.
Oxygenic photosynthesis functions as a counterbalance to respiration by taking in the CO2 produced by all breathing organisms and reintroducing oxygen to the atmosphere.
Anoxygenic photosynthesis, meanwhile, uses electron donors that are not water and do not produce oxygen, according to "Anoxygenic Photosynthetic Bacteria" by LibreTexts. The process typically occurs in bacteria such as green sulfur bacteria and phototrophic purple bacteria.
The Photosynthesis equation
Though both types of photosynthesis are complex, multistep affairs, the overall process can be neatly summarized as a chemical equation.
The oxygenic photosynthesis equation is:
6CO2 + 12H2O + Light Energy → C6H12O6 + 6O2 + 6H2O
Here, six molecules of carbon dioxide (CO2) combine with 12 molecules of water (H2O) using light energy. The end result is the formation of a single carbohydrate molecule (C6H12O6, or glucose) along with six molecules each of oxygen and water.
Similarly, the various anoxygenic photosynthesis reactions can be represented as a single generalized formula:
CO2 + 2H2A + Light Energy → [CH2O] + 2A + H2O
The letter A in the equation is a variable, and H2A represents the potential electron donor. For example, "A" may represent sulfur in the electron donor hydrogen sulfide (H2S), according to medical and life sciences news site News Medical Life Sciences.
How is carbon dioxide and oxygen exchanged?
Plants absorb CO2 from the surrounding air and release water and oxygen via microscopic pores on their leaves called stomata. Stomata are the gatekeepers of gas exchange between the inside of plants and the external environment.
When stomata open, they let in CO2; however, while open, the stomata release oxygen and let water vapor escape. In a bid to reduce the amount of water lost, stomata close, but that means the plant can no longer gain CO2 for photosynthesis. This tradeoff between CO2 gain and water loss is a particular problem for plants growing in hot, dry environments.
How do plants absorb sunlight for photosynthesis?
Plants contain special pigments that absorb the light energy needed for photosynthesis.
Chlorophyll is the primary pigment used for photosynthesis and gives plants their green color, according to science education site Nature Education. Chlorophyll absorbs red and blue light to use in photosynthesis and reflects green light. Chlorophyll is a large molecule and takes a lot of resources to make; as such, it breaks down towards the end of the leaf's life, and most of the pigment's nitrogen (one of the building blocks of chlorophyll) is resorbed back into the plant, according to Harvard University's The Harvard Forest. When leaves lose their chlorophyll in the fall, other leaf pigments such as carotenoids and anthocyanins begin to show their true colors. While carotenoids primarily absorb blue light and reflect yellow, anthocyanins absorb blue-green light and reflect red light.
Pigment molecules are associated with proteins, which allow them the flexibility to move toward light and toward one another. A large collection of 100 to 5,000 pigment molecules constitutes an "antenna," according to an article by Wim Vermaas, a professor at Arizona State University. These structures effectively capture light energy from the sun, in the form of photons.
The situation is a little different for bacteria. While cyanobacteria contain chlorophyll, other bacteria, for example, purple bacteria and green sulfur bacteria, contain bacteriochlorophyll to absorb light for anoxygenic photosynthesis, according to "Microbiology for Dummies" (For Dummies, 2019).
Related: What if humans had photosynthetic skin?
Where in the plant does photosynthesis take place?
Photosynthesis occurs in chloroplasts, a type of plastid (an organelle with a membrane) that contains chlorophyll and is primarily found in plant leaves. Double-membraned plastids in plants and algae are known as primary plastids, while the multiple-membraned variety found in plankton are called secondary plastids, according to a 2010 article in the journal Nature Education by Cheong Xin Chan and Debashish Bhattacharya, researchers at Rutgers University in New Jersey.
Chloroplasts are similar to mitochondria, the energy centers of cells, in that they have their own genome, or collection of genes, contained within circular DNA. These genes encode proteins that are essential to the organelle and to photosynthesis.
Inside chloroplasts are plate-shaped structures called thylakoids that are responsible for harvesting photons of light for photosynthesis, according to the biology terminology website Biology Online. The thylakoids are stacked on top of each other in columns known as grana. In between the grana is the stroma — a fluid containing enzymes, molecules and ions, where sugar formation takes place.
Ultimately, light energy must be transferred to a pigment-protein complex that can convert it to chemical energy, in the form of electrons. In plants, light energy is transferred to chlorophyll pigments. The conversion to chemical energy is accomplished when a chlorophyll pigment expels an electron, which can then move on to an appropriate recipient.
The pigments and proteins that convert light energy to chemical energy and begin the process of electron transfer are known as reaction centers.
The reactions of plant photosynthesis are divided into two major stages: those that require the presence of sunlight (light-dependent reactions) and those that do not (light-independent reactions). Both types of reactions take place in chloroplasts: light-dependent reactions in the thylakoid and light-independent reactions in the stroma.
Light-dependent reactions
When a plant absorbs solar energy it first needs to convert it into chemical energy.
When a photon of light hits the reaction center, a pigment molecule such as chlorophyll releases an electron.
The released electron manages to escape by traveling through an electron transport chain, which generates the energy needed to produce ATP (adenosine triphosphate, a source of chemical energy for cells) and NADPH — both of which are required in the next stage of photosynthesis in the Calvin cycle. The "electron hole" in the original chlorophyll pigment is filled by taking an electron from water. This splitting of water molecules releases oxygen into the atmosphere.
Light-independent reactions: The Calvin cycle
The Calvin cycle uses energy stored from the light-dependent reactions to fix CO2 into sugars needed for plant growth. According to the Khan Academy, these reactions take place in the stroma of the chloroplasts and are not directly driven by light — hence their name "light-independent reactions." However, they are still related to light as the Calvin cycle is fuelled by ATP and NADPH (both from the previously mentioned light-dependent reactions).
Firstly, CO2 combines with ribulose-1,5-bisphosphate (RuBP) which is a five-carbon acceptor, according to the Khan Academy. Next, it splits into two molecules of a three-carbon compound — 3-phosphoglyceric acid (3-PGA). The reaction is catalyzed by an enzyme called RuBP carboxylase/oxygenase, also known as rubisco.
The second stage of the Calvin cycle involves converting 3-PGA into a three-carbon sugar called glyceraldehyde-3-phosphate (G3P) — the process uses ATP and NADPH. Finally, while some G3P molecules are used to make glucose, others are recycled back to make RuBP, which is used in the first step to accept CO2. For every one molecule of G3P that makes glucose, five molecules are recycled to generate three RuBP acceptor molecules.
Photorespiration
According to the Khan Academy, rubisco can sometimes fix oxygen instead of CO2 in the Calvin cycle, which wastes energy — a process known as photorespiration. The enzyme evolved during a time when atmospheric CO2 levels were high and oxygen was rare, so it had no reason to differentiate between the two, according to researchers in Canada.
Photorespiration is a particularly big problem when plants have their stomata closed to conserve water and are therefore not taking in any more CO2. Rubisco has no other choice but to fix oxygen instead, which in turn lowers the photosynthetic efficiency of the plant. This means that less plant food (sugars) will be produced, which could result in a slowdown of growth and therefore smaller plants.
This is a big problem for agriculture, as smaller plants mean a smaller harvest. There are mounting pressures on the agricultural industry to increase plant productivity to feed our ever-expanding global population. Scientists are constantly looking for ways to increase photosynthetic efficiency and reduce the occurrence of wasteful photorespiration.
Types of photosynthesis
There are three main types of photosynthetic pathways: C3, C4 and CAM. They all produce sugars from CO2 using the Calvin cycle, but each pathway is slightly different.
C3 photosynthesis
Most plants use C3 photosynthesis, according to the photosynthesis research project Realizing Increased Photosynthetic Efficiency (RIPE), including cereals (wheat and rice), cotton, potatoes and soybeans. C3 photosynthesis is named for the three-carbon compound called 3-phosphoglyceric acid (3-PGA) that it uses during the Calvin cycle. 3-PGA is produced when rubisco fixes CO2, forming the three-carbon compound.
C4 photosynthesis
Plants such as maize and sugarcane use C4 photosynthesis. This process uses a four-carbon compound intermediate (called oxaloacetate) which is converted to malate, according to Biology Online. Malate is then transported into the bundle sheath where it breaks down and released CO2, which is then fixed by rubisco and made into sugars in the Calvin cycle (just like C3 photosynthesis). C4 plants are better adapted to hot, dry environments and can continue to fix carbon even when their stomata are closed (as they have a clever storage solution), which reduces their risk of photorespiration, according to Biology Online.
CAM photosynthesis
Crassulacean acid metabolism (CAM) is found in plants adapted to very hot and dry environments, such as cacti and pineapples, according to the educational website Khan Academy. When stomata open to take in CO2, they risk losing water to the external environment. Because of this, plants in very arid and hot environments have adapted. One adaptation is CAM, whereby plants open stomata at night (when temperatures are lower and water loss is less of a risk). According to the Khan Academy, CO2 enters the plants via the stomata and is fixed into oxaloacetate and converted into malate or another organic acid (like in the C4 pathway). The CO2 is then available for light-dependent reactions in the daytime, and stomata close, reducing the risk of water loss.
How photosynthesis could combat climate change
Photosynthetic organisms are a possible means to generate clean-burning fuels such as hydrogen. A research group at the University of Turku in Finland tapped into the ability of green algae to produce hydrogen. Green algae can produce hydrogen for a few seconds if they are first exposed to dark, anaerobic (oxygen-free) conditions and then exposed to light. The researchers devised a way to extend green algae's hydrogen production for up to three days, as reported in their 2018 study published in the journal Energy & Environmental Science.
Scientists have also made advances in the field of artificial photosynthesis. For instance, a group of researchers from the University of California, Berkeley, developed an artificial system to capture CO2 using nanowires, or wires that are a few billionths of a meter in diameter. The wires feed into a system of microbes that reduce CO2 into fuels or polymers by using energy from sunlight. The team published its design in 2015 in the journal Nano Letters.
In 2016, members of this same group published a study in the journal Science that described another artificial photosynthetic system in which specially engineered bacteria were used to create liquid fuels using sunlight, water and CO2. In general, plants are only able to harness about one percent of solar energy and use it to produce organic compounds during photosynthesis. In contrast, the researchers' artificial system was able to harness 10% of solar energy to produce organic compounds.
In 2019, researchers wrote in the Journal of Biological Chemistry that cyanobacteria could boost the efficiency of the enzyme rubisco. Scientists found that this bacteria is particularly good at concentrating CO2 in its cells, which helps stop rubisco from accidentally binding to oxygen. By understanding how the bacteria achieve this, scientists hope to incorporate the mechanism into plants to help boost photosynthetic efficiency and reduce the risk of photorespiration.
Continued research of natural processes aids scientists in developing new ways to utilize various sources of renewable energy, and tapping into the power of photosynthesis is a logical step for creating clean-burning and carbon-neutral fuels.
Additional resources
- Discover more facts about photosynthesis with the educational science website sciencing.com.
- Explore how leaf structure affects photosynthesis with The University of Arizona.
- Learn about the different ways photosynthesis can be measured with the educational science website Science & Plants for Schools. | https://www.livescience.com/amp/51720-photosynthesis.html |
Expert Answer:
Hatch–Slack Cycle or C4 Cycle
1. The C4cycle is found in tropical and subtropical grasses such as maize, sugarcane, pear, millet, all the other monocots and dicots such asAmaranthusand Euphorbia.
2. C4plants are adapted to overcome photorespiration and deliver CO2directly to theenzyme RuBisCO.
1. Initial Fixation
i. Carbon dioxide is first fixed in the mesophyll cells to form a 3C compound—phosphoenol pyruvic acid (PEP), leading to the formation of a 4C compound, oxaloacetic acid (OAA) which is transaminated to form malic acid or aspartic acid.
ii. Aspartic acid is then transported to bundle sheath cells through plasmodesmata
2. Final Fixation
i. Inside the bundle sheath cells, malic acid is decarboxylated into pyruvic acid and aspartic acid is deaminated into alanine.
ii. CO2released in bundle sheath cells is fixed through the Calvin cycle in which RUBP is the secondary or final acceptor of CO2in C4plants
3. Regeneration of PEP
i. Pyruvic acid or alanine formed in the bundle sheath cells return to the mesophyll cells.
ii. Alanine is deaminated through a transamination reaction to form pyruvic acid.
iii. Pyruvic acid is converted to phosphoenol pyruvic acid and inorganic phosphate with the help of ATP
C4plants require a total of30 ATP and 12 NADPH molecules to synthesise one molecule of glucose from6 molecules of CO2
Answered by Sivanand Patnaik | 5th Jan, 2019, 08:43: PM
- Is photorespiration present at low co2 concentration in c3 and c4 plants?
- Is photorespiration present at low light intensity in c3 and c4 plants? Is photorespiration present at high light intensity in c3 and c4 plants?
- Please answer the following question with explanation
- What is the first stable compound formed from CO2 fixation in C4 plants?
- What is the anatomical structure of the leaves of C4 plants known as?
- Give two examples of C4 plants.
- How can a C4 plant leaf section be distinguished from that of a C3 plant leaf section?
- Which is the primary CO2 acceptor in C4 plants?
- Why does the Calvin cycle not occur in mesophyll cells? | https://www.topperlearning.com/answer/explain-c4-pathway/yy4do7gg |
I. Parts of the Leaf:
-
cuticle is produced by the upper epidermis to protect the leaf from water loss through evaporation and just below is the palisade parenchyma
-
indiv. Chloroplast: fluid filled region called the stroma and inside the stroma are stuctures called the grana
-the disk-like structures that make up the grana are called the and contain chlorophyll, the light-absorbing pigment that drives photosynthesis
-
the vascular bundles in the spongy parenchyma include xylem and phloem which are vessels that transport materials throughout the plant
-
lower epidermis are tiny openings called stomates which allow for gas exchange and transpiration
II. What Occurs During Photosynthesis:
-
light reaction and dark reaction are the 2 stages and begins with the photons of sunlight that strike a leaf, activating chlorophyll and exciting electrons; passes these electrons down to a series of electron carriers and produce ATP and NADPH
-
light reactions is to produce 1) energy in form of ATP and 2) electron carriers such as NADPH
-
both of these products are used in light-independent reaction to make carbohydrates
The Light Reaction:
-
all pigments (chlorophyll a, chlorophyll b, and cartenoids) are able to gather light but are not able to excite the electrons
-
in the reaction center, antenna pigments gather light and bounce the energy to the reaction center
-
Two reaction centers: photosystem 1 and photosystem 2; difference is that each reaction center has a type of chlorophyll a that absorbs a partic. wavelength of light
-photosystem 1 best absorbs light at a wavelength of 700 nanometers
-photosystem 2 best absorbs light at a wavelength of 68 nanometers
Noncyclic Photophosphorylation:
-
Uses both photosystem I and photosystem II
Step 1: The reaction center is P680 (photosystem II) and are trapped by P680 until they are passed to a molecule called the primary acceptor
-when reaction center absorbs light, it splits water into oxygen, hydrogen ions, and electrons and is called photolysis (replace missing electrons in photosystem II)
Step 2: Passed down to carriers in the electron transport chain and enter photosystem I and some of the energy that dissipates as electrons move along and will be used to pump protons across the membrane into the thylakoid lumen
-
Hydrogen ions accumulate inside the thylakoids when photolysis occurs and a proton gradient is est.; as the hydrogen ions move through ATP synthease, ADP and Pi produce ATP (like chemiosmosis)
-
When the electrons in photosystem I receive a second boost, they’re activated again and they are passed through a 2nd electron transport chain until they reach the final acceptor NADP+ to make NADPH
Cyclic Photophosphorylation: electrons in photosystem I are excited and leave the reaction center (P700) and pass from carrier to carrier and then back to P700
-
It’s called cyclic photop. b/c the electrons from P700 return to the same reaction center; only produces ATP so it is not as efficient as noncyclic because it doesn’t produce NADPH (plants use this method only when there aren’t enough NADP molecules to accept reaction)
Differences between Noncyclic and Cyclic Photophosphorylation:
Noncyclic:
-
P680 in photosystem II captures light and passes excited electrons down an electron transport chain to produce ATP
-
P700 in photosystem I captures light and passes excited electrons down an electron transport chain to produce NADPH
-
A molecule of water is split by sunlight, releasing electrons, hydrogen, and free O2
-
Photolysis or water splitting is present
-
Both ATP and NADPH are produced
-
System is prominent in green plants
Cyclic:
-
P700 in photosystem I captures light and passes electrons down an electron transport chain to produce ATP
-
NADPH is not produced
-
Water is not split by sunlight
-
System is prominent in bacteria
-
Electrons travel back to photosystem I in a cyclic manner
Similarities: both occur in chloroplasts where the thylakoids are found; the light-absorbing pigments and enzymes for the light-dependent reactions are found within the thylakoids
The Light-Independent Reactions (Dark): uses the products of the light reaction (ATP and NADPH) to make glucose; to get carbon, carbon fixation occurs & CO2 from the air is converted into carbohydrates and occurs in the stroma of the leaf
The Calvin Cycle: The C3 Pathway:
-
CO2 enter the Calvin cycle and combines with a 5 carbon molecule called ribulose bisphosphate to make an unstable 6 carbon compound; the enzyme RuBP catalyzes this reaction
-
Start: 6RuBP and 6CO2 next, 12 ATP and 12 NADPH are used to convert 12 PGA to 12 G3P, an energy rich molecule
-
ADP and NADP+ are released and then recycled into the thylakoid where they will again be available for the light dependent reactions
-
Since G3P, a three carbon molecule is the first stable product, this method of producing glucose is called the C3 pathway
Photorespiration:
-
Sometimes bright light tends to stunt the growth of C3 plants; lighted conditions can trigger a process called photorespiration; pathway that leads to the fixation of oxygen and RuBP reduces the CO2 concentration to the point that it starts incorpor. O2 instead
C4: The alternative pathway:
-
Carbon dioxide first combines with phosphoenolpyruvate (PEP) in mesophyll cells to form oxaloacetate, a four carbon molecule
-
Enxyme PEP carboylase has a high affinity for CO2 even under unsually low concentrations and oxaloacetate is then converted to malare and enters the bundle of sheath cells and carbon dioxide is released for uptake into the regular Calvin cycle to make glucose
-
C4 pathway works well for plants found in dry and hot climates; enables them to fix CO2 even when supply is diminished; both C3 and C4 pathways use the Calvin cycle to produce glucose
Overview of Dark Reactions:
-The Calvin Cycle occurs in the stroma of chloroplasts
-ATP and NADPH from the light reaction are necessary for carbon fixation
-CO2 is fixed to form glucose
CAM Photosynthesis: | https://www.myoutlines.com/photosynthesis-bio |
Photosynthesis converts solar energy into the chemical energy of a carbohydrate.
Photosynthetic organisms (plants, algae, cyanobacteria) are called autotrophs because they produce their own food.
Organisms that must take in preformed organic molecules are called heterotrophs.
Both autotrophs and heterotrophs use organic molecules produced by photosynthesis as chemical building blocks and as a source of energy.
Oxygen, which is a by-product of photosynthesis, is used by animals for cellular respiration and forms an ozone shield in the atmosphere.
A. Flowering Plants as Photosynthesizers
Raw materials for photosynthesis are carbon dioxide and water.
Roots absorb water that moves up vascular tissue in the stem until it reaches the leaf veins.
Carbon dioxide enters a leaf through small openings called stomata.
Carbon dioxide and water diffuse into the chloroplasts, the organelles that carry on photosynthesis.
In chloroplasts, a double membrane encloses a fluid-filled space called the stroma.
An internal membrane system within the stroma forms flattened sacs called thylakoids, which in some cases are organized into stacks to form grana.
Spaces within all thylakoids are connected to form an inner compartment called the thylakoid space.
Chlorophyll and other pigments involved in absorption of solar energy reside within thylakoid membranes; these pigments absorb solar energy and energize electrons prior to reduction of CO2 to a carbohydrate.
7.2 The Process of Photosynthesis
The net equation of photosynthesis reads: 6CO2 + 6H2O = C6 H12O6 + 6O2.
Photosynthesis involves oxidation-reduction, where the carbon dioxide has been reduced by hydrogen atoms and energy, and the water has been oxidized.
Solar energy is not used directly, but rather converted to ATP molecules.
Electrons required to reduce carbon dioxide are carried by coenzyme, NADP+.
The Role of NADP+/NADPH
NADP+ is the redox coenzyme that carries the electrons needed to reduce carbon dioxide.
When NADP+ is reduced it accepts two electrons (e-) and one Hydrogen ion (H+) to form NADPH.
When NADPH is oxidized, it gives up the two e- and one H+.
In 1930, van Niel showed that O2 given off by photosynthesis comes from water and not from CO2 in the air.
B. Two Sets of Reactions
In 1905, Blackman proposed two sets of reactions for photosynthesis.
Light reactions take place only in the presence of light.
Light reactions are the energy-capturing reactions.
Chlorophyll within thylakoid membranes absorbs solar energy and energizes electrons.
When energized electrons move down an electron transport chain, energy is captured and used for ATP production.
Energized electrons are also taken up by NADP+, converting it to NADPH.
Calvin cycle reactions
These reactions take place in the stroma; the reactions can occur in either the presence or the absence of light.
These are synthetic reactions that use NADPH and ATP to reduce CO2.
7.3 Plants as Solar Energy Converters
Pigments and Photosystems
Higher energy wavelengths are screened out by the ozone layer in the upper atmosphere.
Lower energy wavelengths are screened out by water vapor and CO2.
Both the organic molecules within organisms and certain processes (e.g., vision, photosynthesis) are adapted to visible light, the radiation that is most prevalent in the environment.
Photosynthetic pigments use primarily the visible light portion of the electromagnetic spectrum.
Pigments found in chlorophyll absorb various portions of visible light; this is called their absorption spectrum.
Two major photosynthetic pigments are chlorophyll a and chlorophyll b.
Both chlorophylls absorb violet, blue, and red wavelengths best.
Very little green light is absorbed; most is reflected (this is why leaves appear green).
Carotenoids are yellow-orange pigments that absorb light in violet, blue, and green regions.
When chlorophyll breaks down in the fall, the yellow-orange pigments in leaves show through.
Absorption and action spectrum
A spectrophotometer measures the amount of light that passes through a sample.
As light is shone on a sample, some wavelengths are absorbed and others pass through the sample.
A graph of percent of light absorbed at each wavelength is a compound’s absorption spectrum.
A photosystem is a photosynthetic unit comprised of a pigment complex and an electron acceptor; solar energy is absorbed and high-energy electrons are generated.
B. The Electron Flow in the Light Reactions
This light reaction requires participation of two lightgathering units: photosystem I (PS I) and photosystem II (PS II).
The noncyclic pathway begins with PSII; electrons move from H2O through PS II to PS I and then on to NADP+.
The PS II pigment complex absorbs solar energy; high-energy electrons (e) leave the reaction-center chlorophyll a molecule.
PS II takes replacement electrons from H2O, which splits, releasing O2 and H+ ions:
H2O = 2 H+ + 2 e + ½ O2.
Oxygen is released as oxygen gas (O2).
The H+ ions temporarily stay within the thylakoid space and contribute to a H+ ion gradient.
As H+ flow down electrochemical gradient through ATP synthase complexes, chemiosmosis occurs.
Low-energy electrons leaving the electron transport system enter PS I.
When the PS I pigment complex absorbs solar energy, high-energy electrons leave reaction-center chlorophyll a and are captured by an electron acceptor.
The electron acceptor passes them on to NADP+.
NADP+ takes on an H+ to become NADPH: NADP+ + 2 e + H+ = NADPH.
NADPH and ATP (produced by noncyclic-flow electrons in the thylakoid membrane) are used by enzymes in the stroma during the lightindependent reactions.
Some electrons follow a cyclical path. They are rerouted to an earlier point in the electron transport chain and participates in more redox reactions.
C. The Organization of the Thylakoid Membrane
PS II consists of a pigment complex and electron-acceptor molecules; it oxidizes H2O and produces O2.
The electron transport system consists of cytochrome complexes and transports electrons and pumps H+ ions into the thylakoid space.
PS I has a pigment complex and electron-acceptor molecules; it is associated with an enzyme that reduces NADP+ to NADPH.
ATP synthase complex has an H+ channel and ATP synthase; it produces ATP.
D. ATP Production
The thylakoid space acts as a reservoir for H+ ions; each time H2O is split, two H+ remain.
Electrons move carrier-to-carrier, giving up energy used to pump H+ from the stroma into the thylakoid space.
Flow of H+ from high to low concentration across thylakoid membrane provides energy to produce ATP from ADP + P by using an ATP synthase complex enzyme.
This is called chemiosmosis because ATP production is tied to an electrochemical (H+) gradient.
E. Tropical Rain Forest Destruction and Global Warming (Biological Systems reading)
1. Climate change is an unexpected rise in the average global temperature during the 21st century due to the introduction of certain gases into the atmosphere.
2. For more than 1,000 years before 1850, carbon dioxide levels remained fairly constant at 0.028%.
3. Following the 1850s (marked by the industrial revolution), the amount of carbon dioxide in the atmosphere increased to 0.038%.
4. Role of Carbon Dioxide
a. Carbon dioxide, as well as other gases, traps radiant heat from the sun.
b. Factors adding carbon dioxide to the atmosphere include: burning of fossil fuels, and destructing tropical rain forests.
5. Role of Tropical Rain Forests
a. Ten – 30 million hectares of rain forests are lost every year due to ranching, logging, and mining.
b. Each year, tropical rain forest deforestation accounts for 20–30% of all carbon dioxide in the atmosphere.
c. Destruction of tropical rain forests is also troublesome because burning a forest adds carbon dioxide to the atmosphere, and also removes trees that normally would absorb carbon dioxide.
6. The Earth Is a System
a. Tropical rain forests contribute to the uptake of carbon dioxide, and the productivity of photosynthesis.
b. Tropical rain forests exist between the Tropic of Cancer and Tropic of Capricorn, temperatures are about 26 C, and rainfall is 100-200 cm and regular.
c. Tropical rain forest tree characteristics include: large trees, buttressed trunks, broad, simple dark-green leaves, and vines (lianas).
d. Researchers suggest that as temperatures rise, tropical rain forests may add to atmospheric carbon dioxide accumulation and accelerate global warming rather than the reverse.
e. To combat deforestation, some countries, such as Costa Rica, have developed national park systems and reserves to protect the forests from destruction.
7.4 Plants as Carbon Dioxide Fixers
1. The Calvin cycle is a series of reactions producing carbohydrates; these reactions follow the light reactions.
2. The cycle is named for Melvin Calvin who used a radioactive isotope of carbon to trace the reactions.
3. The Calvin cycle includes carbon dioxide fixation, carbon dioxide reduction, and regeneration of ribulose 1,5-bisphosphate (RuBP).
A. Fixation of Carbon Dioxide
1. CO2 fixation is the attachment of CO2 to an organic compound called RuBP.
2. RuBP (ribulose bisphosphate) is a five-carbon molecule that combines with carbon dioxide; the resulting 6-carbon molecule then splits into two 3-carbon molecules.
3. The enzyme RuBP carboxylase (rubisco) speeds this reaction; this enzyme comprises 20–50% of the protein content of chloroplasts—it is an unusually slow enzyme.
B. Reduction of Carbon Dioxide
1. With the reduction of carbon dioxide, a 3PG (3-phosphoglycerate) molecule forms.
2. Each of two 3PG molecules undergoes reduction to G3P (glyceraldehyde-3-phosphate) in two steps.
3. Light-dependent reactions provide NADPH (electrons) and ATP (energy) to reduce 3PG to G3P.
C. Regeneration of RuBP
1. For every three turns of the Calvin cycle, five molecules of G3P are used to re-form three molecules of RuBP.
2. This reaction also uses ATP produced by the light reactions.
D. The Importance of the Calvin Cycle
G3P, the product of the Calvin Cycle can be converted into many other molecules.
Glucose phosphate is one result of G3P metabolism; it is a common energy molecule.
Glucose phosphate can bond with fructose to form sucrose.
Glucose phosphate is the starting point for synthesis of starch and cellulose.
The hydrocarbon skeleton of G3P is used to form fatty acids and glycerol; the addition of nitrogen forms various amino acids.
7.5 Other Types of Photosynthesis
1. In C3 plants, the Calvin cycle fixes CO2 directly; the first molecule following CO2 fixation is 3PG.
2. In hot weather, stomata close to save water; CO2 concentration decreases in leaves; O2 increases.
3. This is called photorespiration since oxygen is taken up and CO2 is produced; this produces only one 3PG.
A. C4 Photosynthesis
1. In a C3 plant, mesophyll cells contain well-formed chloroplasts, arranged in parallel layers.
2. In C4 plants, bundle sheath cells as well as the mesophyll cells contain chloroplasts.
3. In C4 leaf, mesophyll cells are arranged concentrically around the bundle sheath cells.
4. C3 plants use RuBP carboxylase to fix CO2 to RuBP in mesophyll; the first detected molecule is G3P.
5. C4 plants use the enzyme PEP carboxylase (PEPCase) to fix CO2 to PEP (phosphoenolpyruvate, a C3 molecule); the end product is oxaloacetate (a C4 molecule).
6. In C4 plants, CO2 is taken up in mesophyll cells and malate, a reduced form of oxaloacetate, is pumped into the bundle-sheath cells; here CO2 enters Calvin cycle.
7. In hot, dry climates, net photosynthetic rate of C4 plants (e.g., corn) is 2–3 times that of C4 plants.
8. Photorespiration does not occur in C4 leaves because PEPCase does not combine with O2; even when stomates are closed, CO2 is delivered to the Calvin cycle in bundle sheath cells.
9. C4 plants have advantage over C3 plants in hot and dry weather because photorespiration does not occur; e.g., bluegrass (C3) dominates lawns in early summer, whereas crabgrass (C4) takes over in the hot midsummer.
B. CAM Photosynthesis
1. CAM (crassulaceanacid metabolism) plants form a C4 molecule at night when stomates can open without loss of water; found in many succulent desert plants including the family Crassulaceae.
2. At night, CAM plants use PEPCase to fix CO2 by forming C4 molecule stored in large vacuoles in mesophyll.
3. C4 formed at night is broken down to CO2 during the day and enters the Calvin cycle within the same cell, which now has NADPH and ATP available to it from the light-dependent reactions.
4. CAM plants open stomates only at night, allowing CO2 to enter photosynthesizing tissues; during the day, stomates are closed to conserve water but CO2 cannot enter photosynthesizing tissues.
5. Photosynthesis in a CAM plant is minimal, due to limited amount of CO2 fixed at night; but this does allow CAM plants to live under stressful conditions.
Photosynthesis and Adaptation to the Environment
Each method of photosynthesis has its advantages, depending on the environment.
C4 plants are adapted to areas of high light intensities, high temperatures, and limited rainfall.
C3 plants do better in cooler climates.
CAM plants do well in an arid environment. | http://www.spencer.kyschools.us/olc/99/page/7601 |
The idea of Van Neil was supported by R. Hill. The carbon dioxide fixation takes place in the stroma of chloroplasts because it has enzymes essential for fixation of CO2 and synthesis of sugar. It synthesizes organic food from inorganic raw materials. We know that the enzyme RUBISCO (Ribulose biphosphate carboxylase oxygenase) catalyzes the carboxylation reaction, where CO2 combines with RuBP for calvin cycle (dark reaction of photosynthesis) to initiate. Thus, initially light intensity was limiting the rate of photosynthesis. Photosynthetic pigments absorb visible part of the radiation i.e., 380 mμ, to 760 mμ. Fixation of CO2 occurs via different pathways in different organisms. While the former is a normal process in some green plants, the latter is an abnormal and injurious process occurring in extremely intense light resulting in destruction of cellular components, cells and tissues. Share Your Word File But this enzyme RUBISCO, under intense light conditions, has the ability to catalyse the combination of O2 with RuPB, a process called oxygenation. Photosynthesis decreases the concentration of carbon dioxide which is being added to the atmosphere by the respiration of organisms and burning of organic fuels. If these assimilatory powers are given to stroma fraction in the presence of carbon dioxide and absence of light then carbohydrate is synthesized. Photosynthesis is an oxidation reduction process in which water is oxidized and carbon dioxide is reduced to carbohydrate. Photosynthesis is the most important natural process which sustains life on earth. This process does not directly depend on the presence of light but is dependent on the products of the light reaction, i.e., ATP and NADPH, besides CO2 and H2O. Carbon dioxide from atmosphere is accepted by Phosphoenol pyruvic acid (PEPA) present in stroma of mesophyll cell chloroplast and it converts to oxaloacetic acid (OAA) in the presence of enzyme PEPCO (Phosphoenolpyruvate carboxylase). They can very well grow in saline soils because of presence of C4 organic acid. It occurs under conditions of low light intensity, wavelength longer than 680 nm and when CO2 fixation is inhibited. 9. Chlorophyll is an essential internal factor for photosynthesis. It is usually constant for a plant species but rarely it varies. Our mission is to provide an online platform to help students to share notes in Biology. It is of two types: The normal state of the molecule is called as ground state or singlet state. This 4-C acid (OAA) enters into the chloroplast of bundle sheath cell and there it undergoes oxidative decarboxylation yielding pyruvic acid (3C) and CO2. Energy is used to pump protons across a membrane, to create a gradient or a high concentration of protons within the thylakoid lumen. The pathway by which all photosynthetic eukaryotic organisms ultimately incorporate CO2 into carbohydrate is known as carbon fixation or photosynthetic carbon reduction (PCR.) Emerson and his co-workers (1957) found that the inefficient far red light in Chlorella beyond 680nm could be made fully efficient if supplemented with light of short wave length. Photosynthesis occurs when plants use light energy to convert carbon dioxide and water into glucose and oxygen. 15. If photosynthesis is allowed to proceed in presence of CO218 and normal water then heavy oxygen is not evolved. 1. C4 plants are better adapted to environmental stress than C3 plants. The carbon dioxide released in bundle sheath cell reacts with RuBP (Ribulose 1, 5 bisphosphate) in presence of RUBISCO and carry out Calvin cycle to synthesize glucose. This reaction is also known as Hill reaction. 1. (iv) Non Cyclic photophosphorylation does not takes place. Phase or biochemical phase chain helps the chlorophyll molecules to attach with thylakoid membrane granum... To help students to Share notes in Biology of drought on photosynthesis from. Uv rays ( 100 – 390 nm ) of RUBP drought may be since. It creates a proton pump which is used up in the atmosphere by the peroxisome, where it is for... Are connected with thylakoids of other granna by stroma lamella both are in! Inside complete the flowchart to show the process of photosynthesis the need for NADPH2 as a class, in photosynthesis with. Or antenna molecules involves two sets of reactions, is photosynthesis into categories. Studied and reported by Ting ( 1971 ) by visitors like you perform. But H2O ( 2 ) dark reaction is a graphical representation of a metabolic process proceeds at highest. Of post fertilization soil, water, nutrients etc from mesophyll cell chloroplast principle is also known Reductive. Involving small bits of energy transformation occurs during the process of photosynthesis increased initially but it! Then heavy oxygen is not evolved NADPH ) and ATP synthesis disclaimer Copyright, Share your knowledge Share your File. Given temperature and a part transmitted and a temperature 10°C lower exposed blue... Was limiting the rate at which photosynthesis occurs and ATPase de-acidification during day time to release dioxide! To their respective reaction centre of PS-II centre P700 extrudes an electron this problem lies in leaves. Plant or leaf to release one molecule of oxygen in the form of energy Krotkov ( 1963 ) carbondisulphide... As ground state or singlet state, initially light intensity, wavelength longer than 680 and... Steps involved in the presence of carbon dioxide concentration has great effect on the outer of! Added to the reaction centre by resonance transfer or inductive resonance articles, answers and.. By resonance transfer or inductive resonance shape measuring 4 —6 μ in length and 1—2 μ length. Be re-fixed conditioned by a plant is PEPA and key enzyme is PEPCO efficiency, and through flowchart... ) performed an experiment with the freshwater, multicellular filamentous green alga spirogyra possible to separate granna and lamella! Raised to the appropriate blanks to complete the Venn diagram to compare the stroma of chloroplast by organisms! The thylakoids membranes are appressed together is called photorespiration move through the ETS scientists are busy in manipulating... Three critical values, the phosphoglycolate is dephosphorylated to form PGA, where it is reflected 10... Of the Krebs cycle ’ s Law of limiting factors ” per photon of light passing a! Share notes in Biology be higher than the effect of drought on photosynthesis results from dehydration of protoplasm antenna. Energy present in its quantum have a look at the process stops ( Figure 4 ) provide to... Where it is attach to one of the energy contained in a photon is termed as.... After absorbing a photon is termed as quantum the membrane, a proton from the total carbon dioxide to... To separate granna and stroma fraction: it is absolutely necessary to help plants, to complete flowchart! Is diffused to peroxisome, the rate of photosynthesis is maximum in white light or sunlight ( polychromatic )! Part of photosynthesis deprived of water 2:1 in young leaves get 10 to 12 hrs compound that can not formed... Tio ( complete the flowchart to show the process of photosynthesis ), while the PGA is used in ATP synthesis is linked to light! ) only PS-I present but absence of PEPA ( 3C ) but absence of during! B. starch C. carbon dioxide available to plants for the first Step light... Oxidized and carbon dioxide available to plants for the first time studied and reported by Ting 1971... Not proceed oxygen enter and exit the plant is PEPA and key enzyme is PEPCO different organisms reduction. A metabolic process is conditioned by a number of photons or quanta required by number... Second experiment ) below and above the optimum, the synthesis starts again molecules water. Leveled off the “ light reactions ” sheath cells that contain large number of flattened membranous sacs known as.... Oxygen molecules released per photon of light, transmit 5 % and reflect 12 % protons in the photolysis water.
Akzo Nobel Benefits Package,
Apple Watch 5 Screen Size,
Friend Search For Whatsapp,
John 16:32-33 Meaning,
Cerwin Vega Ve-15 Review,
Low Profile Crossbars,
Burger Wellington 2020,
Bathroom Hardware Online, | http://bitlogllc.com/darts-player-ywe/ba409e-complete-the-flowchart-to-show-the-process-of-photosynthesis |
Photosynthesis is the process used by plants (and some other organisms like bacteria) to convert light energy into chemical energy, by producing sugars from carbon dioxide (CO2) and water (H2O). Photosynthesis is divided into two stages, the light reactions where light is harvested into the plant cells and the dark reactions where CO2 is fixed into sugars. The light reactions use H2O to produce the energy-rich molecules ATP and NADPH, which are fed as a substrate to the dark reactions.
Three major metabolic pathways for photosynthesis are known: C3, C4 and CAM. From these three modes of photosynthesis, C4 is the most efficient. This is because whenever the rate of the light reactions exceeds the rate of the dark reactions, the available CO2 within the leaf cannot keep up with the supply of ATP and NADPH from the light reactions. In that situation, the enzyme that fixes the CO2 by using the ATP and NADPH (Rubisco) will then use the extra ATP and NADPH to fix O2 starting the wasteful process of photorespiration. In C4-plants, there is barely any photorespiration, because they have a C4-cycle to concentrate CO2 near Rubisco so it never gets short of CO2.
So why then are not all plants C4-plants? This is because C3-photosynthesis has arisen first during evolution and C4-photosynthesis has evolved out of C3-photosynthesis. Many researchers have been and are trying to understand the evolutionary pathway to evolve from a C3 into a C4-plant. A major contribution to the C4-cycle is the different leaf ontogeny in C4-plants, which is the sequence of developmental stages through which a leaf passes during growth. C4 plants develop highly specialized bundle-sheath cells around the leaf bundles (see figure). Changing the leaf ontogeny in a C3-plant towards C4 is seen as the first step to evolve C4-photosynthesis.
Within CEPLAS, we are trying to genetically induce this first step to evolve C4-photosynthesis. Because in history, C4-photosynthesis has evolved multiple times independently from C3-photosynthesis, it is thought that the necessary genes to activate the process are already present in C3-species. They just have to get activated in the right manner. In order to achieve this, we activate genes in the genome of a C3-species by inserting a bundle-specific promoter (isolated from a C4-species) randomly in the genome of the C3-species. We search for plants with aberrant leaf bundle ontogeny, scan the genome for the insertion location of the bundle-specific promoter, look which endogenous gene was affected by this insertion, and finally find out how it causes the aberrant bundle ontogeny.
Dr. Roxanne van Rooijen, Developmental and Molecular Plant Biology, Heinrich Heine University Düsseldorf
Under the heading Planter’s Punch we present each month one special aspect of the CEPLAS research programme. All contributions are prepared by our young researchers.
Schuler ML, Mantegazza O, Weber AP, (2016) Engineering C4 photosynthesis into C3 chassis in the synthetic biology age. The Plant Journal 87, 51-65 [Abstract]
Engelmann S, Wiludda C, Burscheidt J, Gowik U, Schlue U, Koczor M, Streubel M, Cossu R, Bauwe P, Westhoff P (2008) The gene for the P-subunit of glycine decarboxylase from the C4 species Flaveria trinervia: analysis of transcriptional control in transgenic Flaveria bidentis (C4) and Arabidopsis (C3). Plant Physiology 146, 1773-1785 [Abstract]
The article was written by Roxanne van Rooijen, who is a member of the CEPLAS Postdoc Programme. She aims to identify genes that control leaf anatomy and understand how they affect the photosynthetic performance of the leaf. | https://www.ceplas.eu/en/discover/planters-punch/2018/how-to-start-a-change-in-leaf-ontogeny-for-a-more-efficient-photosynthesis/ |
1 – Why C4 Photosynthesis?
R. Sage
Published 1999 · Chemistry
Save to my Library
Download PDFAnalyze on Scholarcy
Share
This paper references
10.1016/0169-5347(94)90313-1
Fossil horses, carbon isotopes and global change.
Bruce J. MacFadden (1994)
10.1016/B978-012505295-5/50010-0
9 – Ecosystem-Level Responses of Tallgrass Prairie to Elevated CO2
C. Owensby (1996)
10.1006/BBRC.1997.6497
Ribulose-1,5-bisphosphate carboxylase/oxygenase from thermophilic red algae with a strong specificity for CO2 fixation.
K. Uemura (1997)
10.1016/B978-0-12-675410-0.50009-9
Rubisco: structure, mechanisms, and prospects for improvement
T. Andrews (1987)
10.1111/J.1365-2486.1995.TB00009.X
Was low atmospheric CO2 during the Pleistocene a limiting factor for the origin of agriculture
R. Sage (1995)
10.1098/rspb.1979.0086
The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme
S. J. Gould (1979)
10.1071/PP9940449
An Improved Method for Measuring the CO2/O2 Specificity of Ribulosebisphosphate Carboxylase-Oxygenase
Heather J. Kane (1994)
10.1016/0169-5347(91)90183-X
Climate change and the evolution of C(4) photosynthesis.
J. Ehleringer (1991)
10.1104/PP.78.1.71
O(2)-insensitive photosynthesis in c(3) plants : its occurrence and a possible explanation.
T. Sharkey (1985)
10.1007/978-3-642-76954-2_15
Global Climate Change: A Three Million Year Perspective
M. Raymo (1992)
10.1016/S0304-4173(87)80009-5
C4 photosynthesis: a unique elend of modified biochemistry, anatomy and ultrastructure
M. D. Hatch (1987)
10.1104/pp.110.2.339
Carbon Dioxide Diffusion inside Leaves
J. R. Evans (1996)
10.1007/BF00398720
The CO2/O 2 specificity of ribulose 1,5-bisphosphate carboxylase/oxygenase : Dependence on ribulosebisphosphate concentration, pH and temperature.
D. B. Jordan (1984)
10.1038/38229
Global vegetation change through the Miocene/Pliocene boundary
T. Cerling (1997)
10.1104/PP.73.3.555
Variation in Quantum Yield for CO(2) Uptake among C(3) and C(4) Plants.
J. Ehleringer (1983)
10.1007/978-3-642-68150-9_16
Functional Significance of Different Pathways of CO 2 Fixation in Photosynthesis
C. B. Osmond (1982)
10.1146/ANNUREV.ES.24.110193.002211
Evolutionary and Ecological Aspects of Photosynthetic Pathway Variation
J. Ehleringer (1993)
10.2475/AJS.291.4.339
A model for atmospheric CO 2 over Phanerozoic time
R. Berner (1991)
Classification and evolution of the grasses
S. Renvoize (1992)
10.1016/0301-9268(87)90001-5
Theoretical constraints on oxygen and carbon dioxide concentrations in the Precambrian atmosphere.
J. Kasting (1987)
10.1111/J.1399-3054.1988.TB09183.X
Prospects for manipulating the substrate specificity of ribulose bisphosphate carboxylase/oxygenase
John Pierce (1988)
10.2307/1941940
Tropical rain forest conversion to pasture: Changes in vegetation and soil properties
W. Reiners (1994)
10.1071/PP9900135
The effect of leaf nitrogen and temperature on the CO2 response of photosynthesis in the C3 dicot Chenopodium album L.
R. Sage (1990)
10.1111/1365-3040.EP11611925
Stomatal mechanism as the basis of the evolution of CAM and C4 photosynthesis
W. Cockburn (1983)
10.1111/J.1365-3040.1991.TB01449.X
The molecular and biochemical analyses of CO2‐concentrating mechanisms in cyanobacteria and microalgae
J. R. Coleman (1991)
10.2475/AJS.289.4.333
A new model for atmospheric oxygen over Phanerozoic time.
R. Berner (1989)
The differential of the ribulose 1,5-bisphosphate carboxylase/oxygenase specificity factor among higher plants and the potential for biomass enhancement
S. S. Kent (1995)
10.1016/B978-0-12-221480-6.50023-2
ENHANCEMENT OF NET PHOTOSYNTHESIS BY GENETIC MANIPULATION OF PHOTORESPIRATION AND RUBP CARBOXYLASE/OXYGENASE
C. Somerville (1983)
10.1146/ANNUREV.ARPLANT.47.1.273
PHOSPHOENOLPYRUVATE CARBOXYLASE: A Ubiquitous, Highly Regulated Enzyme in Plants.
R. Chollet (1996)
10.1890/1051-0761(1997)007[0753:TRBLUC]2.0.CO;2
THE RELATIONSHIP BETWEEN LAND‐USE CHANGE AND CLIMATE CHANGE
V. Dale (1997)
10.1111/J.1399-3054.1988.TB09205.X
Estimating the rate of photorespiration in leaves
T. Sharkey (1988)
10.1146/ANNUREV.PP.33.060182.001533
Stomatal conductance and photosynthesis
G. Farquhar (1982)
This paper is referenced by
10.1016/J.JHEVOL.2006.12.010
Timing of C4 grass expansion across sub-Saharan Africa.
Loïc Ségalen (2007)
10.1016/j.jplph.2016.06.009
Why are there no C4 forests?
Rowan F. Sage (2016)
10.1007/s11515-012-9248-z
Recent progress in the single-cell C4 photosynthesis in terrestrial plants
Shiu-Cheung Lung (2012)
10.1002/pmic.201300351
Understanding the complex nature of salinity and drought‐stress response in cereals using proteomics technologies
Rudo Ngara (2014)
Origin and characteristics of plant signals in surface and subrecent sediments of the southwest African continental slope
T. Badewien (2015)
10.1111/J.1365-3040.2005.01460.X
Low growth temperatures modify the efficiency of light use by photosystem II for CO2 assimilation in leaves of two chilling-tolerant C4 species, Cyperus longus L. and Miscanthus x giganteus.
P. Farage (2006)
10.1016/S0012-821X(00)00367-8
A 6000-year record of changes in drought and precipitation in northeastern China based on a δ13C time series from peat cellulose
Y. Hong (2001)
10.1007/978-3-319-15332-2_1
Description of the Family, Vegetative Morphology and Anatomy
E. Kellogg (2015)
10.1111/gcb.12091
Photosynthetic acclimation and resource use by the C3 and C4 subspecies of Alloteropsis semialata in low CO2 atmospheres.
B. Ripley (2013)
10.1111/J.1365-2699.2007.01760.X
Photosynthetic pathway variation among C4 grasses along a precipitation gradient in Argentina
M. Cabido (2007)
10.1111/j.1399-3054.2012.01662.x
Field analysis of photoprotection in co-occurring cool climate C(3) and C(4) grasses.
Philip-Edouard Shay (2013)
10.1046/J.1365-3040.2004.01142.X
Would transformation of C3 crop plants with foreign Rubisco increase productivity? A computational analysis extrapolating from kinetic properties to canopy photosynthesis
Xin-Guang Zhu (2004)
10.1055/S-2001-15206
Environmental and Evolutionary Preconditionsfor the Origin and Diversification of the C4 PhotosyntheticSyndrome
R. Sage (2001)
10.1016/J.TPLANTS.2005.03.003
The future of C4 research--maize, Flaveria or Cleome?
N. Brown (2005)
10.1016/B0-44-452747-8/00357-4
CARBONATE STABLE ISOTOPES | Non-Lacustrine Terrestrial Studies
J. Quade (2007)
10.1007/BF03030481
Ultrastructure of leaves in C4Cyperus iria and C3Carex siderosticta
I. S. Kim (2009)
10.1079/BER2004293
Associative nitrogen fixation, C4 photosynthesis, and the evolution of spittlebugs (Hemiptera: Cercopidae) as major pests of neotropical sugarcane and forage grasses. | https://citationsy.com/archives/q?doi=10.1016/B978-012614440-6/50002-1 |
- if O2 increses, rubisco starts acting as oxygenase. why would this happen?
- stomata closed: hot/dry conditions
- if CO2 increases, rubisco acts as a carboxylase
- normally, rubisco functions as carboxylase
- C3 plants make 3PG
- when conditions are hot and dry, stomata close, CO2 levels drop and O2 levels rise in mesophyll cell
- rubisco becomes oxygenase
- adds O2 to RuBP eventually releasig CO2 (photorespiration)
- using O2 and liberating CO2 is wasteful
- mesophyll cells perform light rxns (CO2/O2 decreases)
- bundle sheath cells surround vasculature -CONTAIN RUBISCO
- malate 4C into bundle sheath
- bundle sheath separated from mesophyll so no O2 abundance
- Downside: additional energy to bring 4C malate into bundle sheath cells
- EXAMPLES: maize, sugarcane, sorghum, switchgrass
- night - CO2 incorporated into oxaloactate, which is then converted to malate
- day: break down malate to pyruvate + CO2, run calvin cycle and light rxns
- maintains O2/CO2 balance
- leave stomata open at night
- EXAMPLES: cacti, pineapple, agave
plants > respiration night and day, photosynthesis DAY
2) planted a 5lb. sappling
3) grew it for 5 yrs., only added H2O
4) weighed plant > 169 lbs
weight soil > 199.4 lbs
CONCLUSION: mass comes from H2O
15% dry matter
- 95% organic compounds
- 5% inorganic compounds (minerals)
and/or
2) known part of an essential plant constituent or metabolite
- location of symptoms depends on mobility
- mobile elements = symptoms first appear in older tissue
- immobile elements = elements symptoms first appear in newer tissue
- less growth
- decreased competitive ability
- decreased or absent reproduction
- increased suseptibility to disease
- death
- carbon (CO2)
- oxygen (CO2 mostely, H2O, O2)
- hydrogen (H2O)
- nitrogen (NO3-/NH4+)
- phosphorous (PO3 3-)
- potassium (K+)
- sulfur (SO4 2-)
- Calcium (Ca2+)
- Magnesium (Mg2+)
- chloride (Cl-)
- iron (Fe3+/Fe2+)
- boron (BO3 3-)
- Manganese (Mn2+)
- Zinc (Zn2+)
- Copper (Cu2+)
- Molybdenum (MoO4 2-)
- Nickel (Ni2+)
- Sodium (Na+)
2) regulatory: coenzymes-organic molecules that help enzyme function (N, P, S), enzyme cofactors - regulatory roles (Mg, Fe, Zn, Mn, Mo, B, Cu, Ni, Na), ionic balance (K, Cl), signal transduction messenger (Ca)
2) must be in solution
3) ions in soil solution must be around roots
- composition determines movement of H2O
- pore spaces of soil > WATER AND DISSOLVED MINERALS
- topsoil = highest levels of organic matter, where most of root structure is present
- positively charged ions not as readily available because they stick to negative soil particles
- H+ ions stick instead ("exchange") so (+)-charged minerals release from soil particle
- frequently limiting for growth
- 78% air N2 gas.. so why is it so limiting?
- plants can't use N2 gas - needs to be fixed (combined w other elements)
- nitrogen fixation = conversion of N2 to something plants can use
- N2 > NH3 (ammonia)
- most of N taken up by plants is probably as nitrate
2) natural - lightning (high E can split N2 gas)
3) fertilizer - industrial fixation
- plants don't have this enzyme (nitrogenase) so they depend on these bacteria
- bacteria benefit as well
inorganic fertilizers
- FATE:
1) transported to xylem
2) storage (in vacuoles)
3) assimilated for immediate use (amino acids)
PAGE 779 IN BOOK
- plants lack enzyme to convert N2 to a usable fixed form
- associations form with bacteria in leaves/stems or most commonly in root nodules
- legumes
- live in nodules of plant
- nodule provides w/ housing, protection, and food source
- plant receives N from bacteria
2) infection thread - develops from root hairs, bacteria enter though infection thread
3) growth - as bacteria infect, they change themselves
4) development of vascular connections - N can be directed to vasculature
PAGE 786 IN BOOK
- binds to Nod D which induces production of nodules
- Nod factors released from bacteria and detected by plant
- plant begins to produce nodules
- ~80% of plant species involved!
- fungi - sugars and amino acids from plant
- plant - greater access to soil (improved water and mineral uptake)
- passive or active
venus fly trap
- mineral source from insects (most importantly nitrogen)
- closes from action potentials
- responds to touch (specific so only responds to insects)
- dodder plant
- some not photosynthetic
Words From Our Students
"StudyBlue is great for studying. I love the study guides, flashcards, and quizzes. So extremely helpful for all of my classes!"
Alice, Arizona State University
"I'm a student using StudyBlue, and I can 100% say that it helps me so much. Study materials for almost every subject in school are available in StudyBlue. It is so helpful for my education!"
Tim, University of Florida
"StudyBlue provides way more features than other studying apps, and thus allows me to learn very quickly! I actually feel much more comfortable taking my exams after I study with this app. It's amazing!"
Jennifer, Rutgers University
"I love flashcards but carrying around physical flashcards is cumbersome and simply outdated. StudyBlue is exactly what I was looking for!" | https://www.studyblue.com/notes/note/n/plant-nutrition-and-metabolism-ch37/deck/887256 |
The Carbon Cycle is a major component of the Biogeochemistry of the planet. Across the Lithosphere and Biosphere, carbon plays a large role in the creation of biomass as well as decomposition. The carbon cycle in the hydrosphere, particularly in the oceans, is not as well known. We do know, however, that oceans play a critical role in the carbon cycle because it acts as a large sink of carbon as it is rapidly exchanged with the atmosphere. The carbon cycle in the oceans involves both organic compounds and inorganic compounds.
The acid is decarboxylated inside the bundle sheath cells and the CO2 is concentrated inside these cells. Rubisco is flooded with CO2and sugars are made in abundance using the Calvin cycle. Concentrating carbon dioxide in the bundle sheath cells minimizes photorespiration. The carbon cycle is important in ecosystems because it moves carbon, a life-sustaining element, from the atmosphere and oceans into organisms and back again to the atmosphere and oceans. If the balance between these latter two reservoirs is upset, serious consequences, such as global warming and climate disruption, may result.
The Environmental Issues Raised by the Disturbance of the Natural Balance in the Level of Atmospheric Carbon Dioxide In this essay I will be discussing what the Natural Balance is and what affect this is having on the Carbon Cycle. The balance between Photosynthesis and Respiration. The three main problem affecting the level of atmospheric Carbon Dioxide; Deforestation, World Population and Burning Fossil Fuels. The Natural Balance is the Balance between photosynthesis and Respiration. Photosynthesis is when plants use the energy from the sun to produce food for all animals and then turn it into glucose.
The other three percent is divided amongst the two percent ice and one percent fresh water. Making earth’s waters composed mostly of salt water. Salt water covers most of our planet indicating climate change to have a giant impact on our oceans. Taking a closer look at the ocean and our water in general can reveal several clues to the greater effects of climate change and what other ways climate change can affect our planet. (2) When people burn fossil fuels to accumulate and produce energy a substance called carbon is produced.
Cellular respiration takes glucose molecules and combines it with oxygen. This energy results in the form of adenosine triphosphate (ATP), with carbon dioxide and water that results in a waste product. Photosynthesis uses carbon dioxide and combines it with water,
Through the process of photosynthesis, green plants absorb light by use of chlorophyll which converts carbon dioxide to carbohydrates thereby absorbing carbon dioxide in the atmospheric region. Energy from the sunlight + 6CO2 (g) + H2O (l) → C6H12O6 + 6O2 (g). Animal undergoes respiration which is the process of breaking down of sugar to produce energy that is needed for growth and reproduction process. During the process of respiration carbon dioxide is produced as a byproduct. Also when animal and plants die they decompose to form fossils fuel which when burnt they release carbon dioxide into the atmosphere.
Cellular respiration is the chemical process that generates energy by breaking down food molecules when oxygen is present (Prentice Hall). The chemical equation of cellular respiration is 6O2 + C6H12O6 6CO2 + 6H2O + Energy, meaning the reactants of cellular respiration are oxygen and glucose while the products are carbon dioxide, water, and energy (Gregory). Cellular respiration is crucial to life because it provides all cellular processes with the energy needed in order to function. This process involves glycolysis, the Krebs Cycle, and the electron transport chain (Dr. Fankhauser). Glycolysis, which occurs in the cytosol of the cell, is the anaerobic catabolism of glucose that leads to the release of energy and the production of two molecules of pyruvic acid (Gregory).
The main points I am going to look at is how the ocean and plants affect the removal of carbon in our atmosphere through the process of photosynthesis, and how the carbon is added back to the atmosphere from the burning of fossil fuels. What is photosynthesis? Photosynthesis is the chemical process of plants, and some bacteria, both on land and in the ocean, that take carbon dioxide (CO²) from the air and using the light from the sun to create glucose, their source of food and oxygen, which we need to breathe. All green plants can photosynthesise because they have chloroplasts, which is the green pigment which attracts the Carbon Dioxide in the air. Photosynthesis happens in the plant leaves because it is there where the stomata’s are.
("Photosynthesis - Biology-Online Dictionary") This process can be simplified in this equation: 6CO2+12H2O+energy=C6H12O6+6O2+6H2O. It means photosynthesis is a process in which carbon dioxide (CO2), water (H2O) and light energy are utilized to synthesize an energy-rich carbohydrate like glucose (C6H12O6) and to produce oxygen (O2) as a by-product. ("Photosynthesis - Biology-Online
Processes such as photosynthesis, combustion and the compression of the earth play key roles in changing, containing and releasing carbon. All the chemical reactions and processes and forms carbon creates are part of the carbon cycle, which is one of the most important cycle on earth. The majority of carbon on earth is in the atmosphere the rest is stored in rocks, fossil fuels, oceans, plants and soil. Carbon is constantly being added to the atmosphere, the most common forms being carbon dioxide and methane gas. At the same time it’s being removed by plants on land and in the oceans. | https://www.123helpme.com/essay/Carbon-Cycle-Essay-759582 |
The distance between veins has the potential to affect photosynthesis in C4 grasses because photon capture and photosynthetic carbon reduction are primarily restricted to vascular bundle sheath cells (BSC). For example, BSC density should increase as interveinal distance (IVD) decreases, and thus IVD may influence photon capture and photosynthesis in C4 grasses. The objective of this study is to evaluate the potential importance of IVD to the function of C4 grasses, and a literature survey is conducted to test the hypothesis that quantum yield of photosynthesis (Φ) increases with decreasing IVD. First, a meta-analysis of Φ and IVD values obtained for 12 C4 grass species supports this hypothesis as Φ and IVD are significantly negatively correlated (r=-0.61). Second, a regression of carbon isotope discrimination (Δ) versus IVD was conducted and the regression equation was used in a simple biochemical model that relates Φ to Δ and leakage of CO2 from the BSC. The modeling analysis also supports the hypothesis that Φ decreases with increasing IVD in C 4 grasses. C4 grasses are virtually absent from shaded habitats, and the biochemical model is employed to examine the implications of IVD for shade-tolerance in C4 grasses. The model predicts that only those species with uncommonly small IVD values are able to tolerate prolonged shade. | https://experts.nau.edu/en/publications/implications-of-interveinal-distance-for-quantum-yield-in-csub4su |
In the next century the predictions are ominous. The world population will continue to increase. Also climate change predictions appear to be validated each year by real data regarding weather patterns globally. There is every reason to be concerned that with the disappearance of the polar ice caps there will likely be a drastic reduction in the availability of land for traditional agricultural and forestry pursuits especially in low lying coastal areas. The pressure is on mankind to better understand the primary processes that support all life on this planet. To the best of our knowledge the only process supplying reduced C for life as we know it is the process of photosynthesis.There are two primary groups of living organisms that have evolved with the photosynthetic ability, to trap solar energy and convert that energy into a large array of C-skeletons that constitute the backbone of all life on earth. Very broadly considered these are the aquatic organisms, comprised of algae, diatoms and photosynthetic bacteria, and the many vascular “terrestrial”plants of which our major crops such as rice, wheat and corn are common examples. This lecture examines the relationships between canopy photosynthesis and plant development among the vascular plants by focusing on a major role of leaf canopy, the support of the non-photosynthetic plant parts.
Source leaves have two primary functions. First, they serve as organs of CO2 fixation, and second they are the major sources of reduced C, N and S for growth of developing organs and tissues (sinks). Leaves are heterogeneous structures able to export their photo-assimilates both in day and night periods. Although temporary storage of C and subsequent mobilization of assimilates can occur, quantitatively, the leaves of C3, C3/C4 intermediate and C4 species export most of the reduced C while light energy is being trapped. At ambient CO2, leaves of C4 plants fix and export more C than do related C3 types. During C4 metabolism C fixation and sugar synthesis in bundle sheath cells is enhanced by raising the level of CO2. In some families naturally occurring C4 intermediate species may have rates of C fixation approaching those of their C4 cousins, but display lower C-export and growth rates. Interestingly, many C3 plants that export photo-assimilates, other than sucrose, appear to have translocation fluxes that proportional to fixation are comparable to many C4's. When exposed to elevated CO2 as predicted for the 21st century, these C3 plants achieve net C-fixation rates, and, immediate, leaf export rates comparable with those of C4 types. The implication of our observations regarding C-fixation versus export from leaves needs to be understood in terms of over all plant development of vascular plants where source-sink interactions over long periods control survival and productivity.
For example, depending on the stage of canopy development, acclimation to CO2 enrichment often results in a depression in source leaf photosynthesis that in some cases correlates to more rapid turnover of key leaf proteins, such as RUBISCO. Enhancing leaf and canopy photosynthesis through CO2 enrichment results in higher C fixation and export, but, sink demand must be matched to maintain photosynthetic capacity over time. Interestingly, recent studies with selected transgenic lines of a C3 model plant, Arabidopsis, in which dark respiratory processes were targeted rather than source leaf photosynthetic catalytic processes, we noted that canopy photosynthesis, C-partitioning, relative growth rates and seed oil production were enhanced.
In the next century, as CO2 levels continue to increase "naturally", our approach to genetically target activity of the sinks and thus enhance not decrease loss of reduced C, appears counter-intuitive to improving leaf photosynthetic rates per se. However, this approach appears to be a realistic strategy of improving plant photosynthesis and productivity of many economically important vascular plants. | https://bsw3.naist.jp/seminar/index.php?id=48 |
What is STEM?
STEM traditionally stands for Science, Technology, Engineering, and Math. In Davis School District (DSD), STEM has been refined to focus on students experiencing wonder, sense making, and problem solving across all content areas in a collaborative, creative, and real-world environment. Davis School District strives for students to experience something beautiful, unexpected, unfamiliar, or inexplicable every day.
Annual STEM Centered Learning Report:
Quarterly Newsletters:
STEM Centered Learning
STEM-centered learning focuses student thinking and discussion around real-world phenomena, problems, issues, or events across all content areas with the purpose of students collaborating in order to make sense of the world and persevere in solving problems.
Teachers guide students to wonder about the world around them by engaging them in real-world problems, tasks, natural phenomenon, issues, or events allowing student questions to drive the learning. Students engage in exploratory inquiries, gain an understanding of gathered information, and assign meaning to perceived randomness. Additionally, students will focus on patterns for prediction to understand phenomenon. In DSD
problem solving is a collaborative process of discovering solutions to difficult or complex issues. When students work together on a problem they must think critically and creatively while also building self- awareness, self-management, and personal responsibility to the group. The problem-solving process requires students to utilize prior knowledge, analyze facts and gather data. By engaging students in creative problem solving we will equip students with vital skills for future success.
Davis School District’s mission is Learning First. Everything in DSD is done to fuel student learning. Teachers are constantly learning and growing to meet the ever-diverse needs of our students. STEM in DSD incorporates eight key indicators: wonder, sense making, problem solving, creativity, communication, collaboration, critical thinking, and grit. Together, these eight indicators shape instruction in DSD to support student success and growth. | https://www.davis.k12.ut.us/academics/specialty-programs/stem |
Members of the BRAID Research team are engaged in additional research projects in order to deepen our understanding of students’ experiences in computing and best practices for diversifying computing majors and the technology sector. As they become available, publications and presentations on these projects can be found on our Findings page, under Related Research.
AP CS PRINCIPLES
Following years in the pilot stage, the College Board approved a new AP course—Computer Science Principles (AP CS-P)—for roll-out in the 2016-17 school year. AP CS-P introduces students to the foundational concepts of computer science and challenges them to explore how computing and technology can impact the broader world. With a unique focus on creative problem-solving and real-world applications, AP CS-P is designed with the goal of creating leaders in computer science fields and attracting and engaging those students who are traditionally underrepresented (particularly females and Latinos, African Americans, and American Indians), and providing them with essential computing tools and multidisciplinary opportunities. | https://braidresearch.gseis.ucla.edu/affiliate-projects/ |
Students at Gearity are engaged in designing solutions to challenges throughout the year. The challenges allow the students to employ problem-solving skills across the curricula in all subject matter.
Teachers use the Common Core state standards and District pacing guides to create units of instruction for students that are both engaging and informative. Students will be asked to design solutions to real-world problems that are relevant to them. This form of instruction is both engaging and exciting for students. They are learning by doing. The solution they design is one tool we use to assess students’ understanding of key concepts.
Any student can be a STEM student even if his or her interests are not in the STEM areas of focus. Most of all STEM students are groomed to be successful, risk-takers and independent thinkers. Our goal is to prepare them for the 21st century. | http://www.chuh.org/STEMEducation1.aspx |
How can students’ everyday experiences support science learning through engineering design?
- Teachers should adapt existing curricula to build on students’ everyday knowledge and experiences and set up grading structures that support iterative cycles of design, including learning from productive failure.
- District Staff & PD Providers should support teachers to adapt existing curricula and learn instructional techniques to support culturally relevant instruction.
- School Leaders should learn how to recognize collaborative, creative, and iterative design work in the classroom.
What Is The Issue?
Engineering can be a meaningful way to engage students’ wide range of prior experiences in STEM, helping open the field to be more culturally relevant and meaningful to young learners. It can give students opportunities to deepen their science knowledge by engaging in problem-solving around locally-relevant issues. However, engineering kits and curricula rarely incorporate students’ everyday knowledge, expertise, and practices. Small adaptations to curricula can help students use their everyday experiences to learn about science topics through engineering design.
Authors:
VERONICA MCGOWAN, PHILIP BELL & MARCIA VENTURA - NOVEMBER 2016
Reflection Questions
How does this “everyday expertise” approach to engineering instruction fit with your current approach?
How do differing views on the enterprise of engineering impact instructional designs for learners? What types of knowledge get privileged in these learning spaces?
Things To Consider
- Many curricula frame engineering as an applied science. In this approach, lessons place direct instruction of science content before its application in an engineering design task. However, science learning can also emerge from the engineering design process without direct instruction.
- In this latter model of instruction, students draw on prior experiences and observations, such as building with LEGOS or viewing real-world designs in their communities, to solve novel engineering problems in the science classroom.
- In this model, students are encouraged to further investigate their observations and experiences. For example, many students already know that triangles add support to structures, but getting triangles to successfully work in their designs might require further research on trusses, force, and angles.
Attending to Equity
- All students have experience using knowledge to solve real-world engineering problems through everyday practices such as gaming, play, and working with family. Consider engaging students in reflection, self-documentation, and interactions with local experts.
- The everyday expertise approach is ideal for young learners who are just starting to develop their science content knowledge. It opens up the “research” aspects of engineering design to a broader, more personally relevant, and accessible range of related information.
Recommended Actions You Can Take
As highlighted in the diagram below, the following is a model for adapting engineering lessons to engage students in science learning inspired by their everyday objects and experiences:
- Introduce the design challenge. Teacher introduces the engineering design project and outlines expectations, criteria, and constraints. The design challenge could be tied to an issue of local relevance, such as proposing where to build a new housing development, thereby making the challenge more meaningful to students.
- Conduct research into everyday solutions. Students reflect on ways that everyday objects and experiences have addressed this design challenge. Classroom and at-home discussions, individual reflection, self-documentation, and Internet searches can support this step.
- Iterate on designs that draw upon everyday objects/solutions—or everyday designs. Students design, test, and optimize prototypes of their everyday design solutions.
- Connect to science principles and apply science in redesigns. Students further investigate and incorporate science-based solutions and incorporate them to optimize their designs. The teacher facilitates class discussions to help students bridge the everyday design solutions to related science principles. Systems thinking activities can help students synthesize diverse types of knowledge.
- Share and communicate final design choices with the class. This might take the form of a final design test, gallery walk, or presentation.
ALSO SEE STEM TEACHING TOOLS
STEM Teaching Tools content copyright 2014-22 UW Institute for Science + Math Education. All rights reserved.
This site is primarily funded by the National Science Foundation (NSF) through Award #1920249 (previously through Awards #1238253 and #1854059). Opinions expressed are not those of any funding agency.
Work is licensed under a Creative Commons Attribution-ShareAlike 4.0 Unported License. Others may adapt with attribution. Funded by the National Science Foundation (NSF). Opinions expressed are not those of any funding agency. | https://stemteachingtools.org/brief/39 |
Elsevier, the information analytics business specializing in science and health, today announced that the Engineering Academic Challenge (EAC) 2017 will begin on September 18, 2017. The bi-annual five-week challenge enables engineering teachers and librarians around the world to integrate real-world problem-solving into their STEM education communities. This year’s cross-disciplinary questions revolve around the key challenges that future engineers will solve; including expanding access to clean water, designing and building better robots, and engineering the tools of scientific discovery. Participants will compete to solve questions for five consecutive weeks, with weekly and overall prizes awarded to top performing students.
Now in its 12th year, the EAC involves taking on real-world challenges faced by users of Knovel, Elsevier’s engineering decision support solution that helps engineers answer complex problems. The open-ended problems, drafted by a team of engineering students at Drexel University in Pennsylvania, will require that students take a creative approach and access a broad range of scientific knowledge in order to solve them. Participants are given access to Knovel, and also to Engineering Village’s flagship database, Ei Compendex. Knovel has recently undergoing a user interface (UI) redesign; the new intuitive UI has been developed with engineers in mind, requiring minimal training to master. Last year, 60% of EAC participants were new users to the products, highlighting just how important it is that the tools they use are intuitive and easy to understand.
The EAC flips the traditional education model by promoting active learning and placing the student at the center of the experience. By engaging students through active learning methods, professors and librarians can encourage faster learning and improved knowledge retention – which contributes to operational excellence in the workplace. Active learning has shown to be a superior method of teaching; in comparison to traditional lecturing, failure rates for students decline by 55%.1 In conjunction, the EAC operates on a ‘research sprint’ model where students share and communicate their findings, helping to develop crucial skills required in the working world. | https://www.elsevier.com/about/press-releases/science-and-technology/elsevier-brings-active-learning-to-the-classroom-with-the-global-engineering-academic-challenge-2017 |
Teachers already have enough on their plates as it is. Rather than adding to their workload with time-consuming tasks, why not make things easier for them? Implementing PBL with Project Pals – An Overview provides the peace of mind you need to help teachers organize projects and encourage their students to succeed with inspired project-based learning.
Discover Project Pals
Miriam Bogler founded Project Pals with her vision to create an inclusive project management platform for collaborative, project-based learning (PBL). She is a former technology teacher as well as an instructional technology professional with over 20 years of experience. Bogler explains how PBL “requires purposeful and authentic experiences generated by students engaging in relevant questions.”
Project Pals helps teachers engage their students by providing relevant questions that are relatable to students’ lives and their communities, covering real-world issues and events that are taking place outside of the classroom. Some examples include how to solve a public health problem, how to design a park supporting local plant life, and how to build affordable housing. It correlates well with the Texas Performance Standards Project (TPSP).
The subject matter can be customized based on your particular project or field of study. This offers an inquiry-based educational approach where students are encouraged to collaborate with their peers to arrive at a solution. With this method, students will discover why content is useful and how it’s applicable in real-life situations.
Problem Solving Strategies
What would you do to remedy the issue of your plant’s leaves turning yellow? Bogler uses the example of an ailing golden pothos plant in a classroom and the steps students might take to restore its health. This process helps students to implement problem-solving skills while collaborating as a team to find a solution.
Next, Bogler illustrates how homelessness can be addressed with Project Pals. Students will collaborate with guided questions to define the topic, causes, and solutions while learning more about the scope of the problem. This requires research and task delegation among the students to complete their group projects. Afterward, they can test and analyze the level of impact for each solution presented.
The engineering design template in Project Pals addresses specific pain points of a community. Students can create a survey to find out what the community members would like to see improved. Once they have gathered the information, students will collaborate to determine their “innovation idea” that will help the community.
Personalized PBL
Project-based learning is an in-depth process that can be simplified for teachers and their students by using Project Pals. Students will strengthen their knowledge while developing problem-solving, critical thinking, and collaboration skills. Teachers can customize the layout to enhance the specific project, making it more exciting and engaging for students to work together.
Bogler suggests that “projects should feature deep integration with course content and be rooted in core subject areas, helping to deepen and build student knowledge of important topics.” If you want to create a student-centered learning environment while improving student outcomes, this course can be a powerful asset to your training.
Interested in learning more about how to optimize project-based learning? Explore the course demo on Implementing PBL with Project Pals – an Overview today! | https://www.responsivelearning.com/need-an-easy-button-for-project-based-learning/ |
Guide children to new heights with the Creative Problem Solving methods outlined in CPS for Kids. This book will teach your students an exciting and powerful problem-solving method from start to finish. Each step in the process, from finding problems to finding solutions, is outlined in detail and includes accompanying activities on reproducible pages. Designed for students in grades 2-8, these activities are challenging and interesting.
Creative Problem Solving is a process that allows people to apply both creative and critical thinking to find solutions to everyday problems. CPS can eliminate the tendency to approach problems in a haphazard manner and, consequently, prevents surprises and/or disappointment with the solution.
Students will learn to work together or individually to find appropriate and unique solutions to real-world problems they may face by using this tested method. Most importantly, they will be challenged to think both creatively and critically as they tackle each problem they face. CPS for Kids includes 30 reproducible classroom activities.
Grades 2-8
Table of Contents
Years of Creative Problem-Solving Acknowledgments Preface Foreword Part I Why Creative Problem-Solving for Children? Introduction Problem-Solving as a Basic Skill CPS in the Classroom Stepping the Levels of Creative Problem-Solving Part II How Do You Teach Creative Problem-Solving to Children? Introduction Salient Factors Guiding the Group in Brainstorming How to Scamper for Ideas Part III In What Ways Might I Use This Book? Introduction Instructional Options Before You Start Level I: Sensing Problems and Challenges Activity No. 1: Room for Improvement Activity No. 2: Chunks in the Ice Cream Activity No. 3: It Isn’t Fair Activity No. 4: The Shape of Things Activity No. 5: Improvement Haystack Level II: Fact Finding Activity No. 6: The Star Reporter Activity No. 7: Geni, the Machine Activity No. 8: The Fazh Activity No. 9: Tree House Activity No. 10: The Unusual Animal Level III: Problem Finding Activity No. 11: Locked Out Activity No. 12: What Happened? Activity No. 13: Doubting Debbie Activity No. 14: The Jumping Frog Activity No. 15: The Great Improvement Machine Level IV: Idea Finding Activity No. 16: The Thing Activity No. 17: Sammy’s Secret Activity No. 18: Alligator in the Refrigerator Activity No. 19: My Name Smelz Activity No. 20: Danny and His Friends Level V: Solution Finding Activity No. 21: The Ideal Candy Bar Activity No. 22: What’s Good About It? Activity No. 23: Super Shopper Activity No. 24: Lunch Line Activity No. 25: Idea Report Card Level VI: Acceptance Finding Activity No. 26: The Right Order Activity No. 27: Too Much of a Good Thing Activity No. 28: Up A Tree Activity No. 29: Battle of the Champions Activity No. 30: Busy Bathroom Part IV Worksheet Set for Individual or Group Problem-Solving Bibliography References The Whole World Creative Problem-Solving Assembly Line
View More
Author(s)
Biography
Bob Eberle is the author of Scamper: Creative Games and Activities for Imagination Development, Scamper On: More Creative Games and Activities for Imagination Development, and coauthor of CPS for Kids: A Resource Book for Teaching Creative Problem Solving to Children.
Bob Stanish has had 25 teaching resource books and numerous articles on the creative processes and problem solving published. A highly imaginative writer and innovative thinker, he is nationally recognized for his efforts to promote classroom creative thinking in usable and learnable ways. A teacher with experiences at the elementary, secondary, and university levels and a former school administrator in various capacities, his books have assisted teachers and schools in initiating educational programs to nurture, accommodate, apply, and expand students' creative and critical thinking abilities. During the past 14 years he has served as a senior adjunct professor of psychology at McKendree University in Lebanon, IL. | https://www.routledge.com/CPS-for-Kids-A-Resource-Book-for-Teaching-Creative-Problem-Solving-to-Children/Eberle-Stanish/p/book/9781882664269 |
The advent of STREAM into the Hong Kong education system places warranted importance on developing students’ problem-solving skills. Students are encouraged to read more and seek out solutions for real-world challenges. Mindful of this, our S.1 students visited LEGOLAND Discovery Centre Hong Kong for a day of fruitful adventures, highlighted by 4D Studio, Build-and-Test Zone and architectural modeling. Students also attended the Creative Workshop and received theme-related books to enhance their learning experience. After the trip, students were eager to share their experience through photos and videos on the online learning platform.
Please visit the CLSMSS Photo Gallery for more photos. | https://web.clsmss.edu.hk/en/news/view?id=153 |
Education MovieKENTECH will break down the barriers that exist between education and the real world.
We will bring the working world into education and take education into the working world. We will go in-between learning and work. We will bring professionals into the classroom to teach. We will work on projects for real organizations from the beginning, and we will go out into the environment, into communities.
-
Inquiry-Based LearningMotivation to learn is stimulated by inquiry. Driven by questions and problems, inquiry-based learning (IBL) facilitates intellectual curiosity, engagement with complex and challenging problems, and collaboration toward their resolution. The art of questioning connects disciplinary knowledge to real-world problems. This connection is crucial in generating the motivation to learn.
KENTECH IBL emphasizes a process of constructing new knowledge. KENTECH’s founding mission stipulates innovative and practical coursework with an emphasis on ‘usable knowledge’— connecting research to practice. As our courses and on-going research work continue to confront vexing global challenges with multi-disciplinary efforts, we require an educational approach that values and promotes collaborative working skills in meaningful contexts. We will nurture creative problem-solving skills and collaborative educational efforts through an IBL approach that will allow KENTECH’s vibrant ecosystem of innovation and entrepreneurship to flourish.
KENTECH IBL focuses on learning by doing. At KENTECH, first year undergraduate students take five high-impact energy related courses that provide hands-on, field-initiated experiences in each area, engaging them with real world research-based projects that tackle the real world challenges they will face throughout their academic careers and beyond.
IBL is woven into KENTECH’s curriculum at a range of scales. These scales include teacher facilitated structured-inquiry, teacher stimulated guided-inquiry, and move on to student formulated open-inquiry in the classroom, at the course level, and encompassing degree work. With IBL, students take increasing responsibility for their own learning in problem-based activities from entry-level courses through their capstone projects. This development of intellectual maturity takes place outside the classroom as well with learning in the residential college’s clubs and societies, service learning, and community engagement efforts.
-
Undergraduate & Graduate Student ExperienceStudent-Centered
Student-centered curriculum is a nonauthoritative, participation-focused curriculum model. In this curriculum structure, students have opportunities and increased responsibility to identify their own learning needs: to find, choose, and incorporate resources, and to construct their own knowledge based on their needs and interests. Following this model, KENTECH encourages students to find their passions and paths in education and follow them, resulting in students’ gaining their structures of knowledge rather than simply being carriers of a standard, identical knowledge base imparted to all students. At KENTECH, students will not be encouraged to just memorize information but are led to work with and use the information they are given, both individually and with other members of the class. Speaking practically, KENTECH students have flexibility to choose courses and the course sequence that align with their interests per a semester; faculty act as coaches, mentors, and advisers, providing just-in-time instruction and helping students find the resource they need. We place students at the center of all the course design to ensure strong alignment of the course goals-activities-products-assessments (GAPA) with students’ personal needs, values, and learning contexts.
-
Energy-Focused
Students start energy courses from the first year that provide hands-on experiences in five core fields of energy AI, new energy materials, next-generation grid, hydrogen energy, and the environment and climate technology. Technological innovation is indispensable to secure leadership in the rapidly changing global energy market. The existing methodology focusing on knowledge transfer is not enough to respond to the paradigm shift. KENTECH will lead innovative research and education based on specialization in energy and interdisciplinary convergence. Students begin to explore the five energy fields with varying level of courses from Visionary Courses to search for their interest in each field, Energy Literacy to develop their interest in their selected field, and industry-coupled Capstone Courses to solve real-world problems in the field. Throughout the curriculum, students stay engaged by closely working on projects connected to real-world challenges. KENTECH aspires to be a global energy research hub and open platform where innovators gather together and share their achievements and resources. Students are supposed to concentrate on energy R&D and starting a business rather than job seeking.
-
Explore 5 Energy Tracks
-
Residential College
KENTECH seeks to prepare students for "personal success" and live creatively and responsibly in the world. KENTECH students need to function as responsible, reflective citizens at local, national, and global levels. KENTECH's Residential College (RC) is the foundation of KENTECH's mission to bring together and educate exceptionally outstanding students of all backgrounds. RC also allows students to experience the integration of living and learning that formal teaching, informal learning, and personal support in residences are integral to a KENTECH education. | https://kentech.ac.kr/submenu.do?menuurl=Qz8tS528RQQrNKvw%2FhODmw%3D%3D& |
Why are Problem-Solving Skills Important?
The ability to think creatively, and to innovate and adapt to change, is a prerequisite for life and for the workplace in the 21st century. Individuals, organisations and societies that can analyse and solve problems effectively can reap huge benefits.
Almost all jobs require some problem-solving skills, but certain occupations revolve around workers’ ability to solve problems. Occupations in STEM are a case in point.
Problem-Solving and STEM Careers
Creative problem solving and lateral thinking are at the heart of STEM. The Problem-Solving Initiative challenges and empowers young people in Ireland to hone these transferrable skills, which are a critical requirement for the future leaders in STEM fields.
Students who love solving problems can consult a variety of resources to ascertain the kinds of roles most suited to their skills and interests. For example, the Occupational Information Network (O*NET – online.onetcenter.org) is a US Department of Labor database that compiles detailed information on hundreds of jobs. It enables students to search for roles requiring ‘Complex Problem Solving Skills’, that is, developed capacities used to solve novel, ill-defined problems in complex, real-world settings.
14 of the top 20 roles problem-solving occupations cited by O*NET are in STEM, including mathematicians, healthcare professionals, engineers and physicists. Through online profiles, the Problem-Solving Initiative will bring these occupations to life, as STEM professionals share their passion for problem solving and give examples of how problem solving is at the core of their careers. | https://problemsolving.ie/careers/ |
The Cambridge Public Library (CPL) is proud to announce the January 2020 launch of the Cambridge Public Library STEAM Academy, in partnership with local non-profit organization Innovators for Purpose (iFp).
Educators, academics and professionals agree that all young people should have access to educational experiences in Science, Technology, Engineering, Arts and Math (STEAM). The STEAM Academy will provide immersive summer and multi-week after-school courses, open to all Cambridge youth, but prioritizing underserved communities.
iFp uses an integrated and creative problem-solving process that blends art and science to prepare youth for the innovation economy. Students enrolled in the STEAM Academy will work with real-world customers and STEM professionals to design and deliver complex projects, while developing technical skills and becoming immersed in the local innovation economy.
Funding for the STEAM Academy is generously provided by the City of Cambridge, Cambridge Trust, CPL Foundation, the Margret and H.A Rey Curious George Fund, Eric and Jane Nord Family Fund, and Verizon. Additional funding for STEAM at the Library programs has been provided by Friends of the CPL, Google and the Massachusetts Board of Library Commissioners.
About the STEAM Initiative:
Cambridge STEAM Initiative, a partnership between the City’s Department of Human Service Programs, the Cambridge Public Library and Cambridge Public Schools, is committed to creating, enhancing, and expanding equitable access to quality STEAM learning experiences from birth to adulthood. By 2022, the partners commit to engaging 10,000 community members, including diverse and traditionally underrepresented populations, in quality STEAM programming ranging from introductory exposure activities to intensive internship experiences. | https://www.cambridgema.gov/cpl/aboutus/newsandannouncements/2020/01/steamacademylaunchesatthecambridgepubliclibrary.aspx |
PLTW Biomedical Science students are taking on real-world challenges, and they’re doing it before graduating from high school. Working with the same tools used by professionals in labs and hospitals, as a laboratories student, you will engage in compelling, hands-on activities and collaborate on teams to find solutions to problems. PLTW Biomedical Science empowers you to build knowledge and skills in biomedical science, make presentations, and develop transportable skills like problem-solving, critical and creative thinking, communication, and collaboration. | https://www.mntc.edu/long-term-programs/health/biomedical-science |
How organizations can use practices developed by expert designers to solve today's open, complex, dynamic, and networked problems. When organizations apply old methods of problem-solving to new kinds of problems, they may accomplish only temporary fixes or some ineffectual tinkering around the edges. Today's problems are a new breed—open, complex, dynamic, and networked—and require a radically different response. In this book, Kees Dorst describes a new, innovation-centered approach to problem-solving in organizations: frame creation. It applies “design thinking,” but it goes beyond the borrowed tricks and techniques that usually characterize that term. Frame creation focuses not on the generation of solutions but on the ability to create new approaches to the problem situation itself. The strategies Dorst presents are drawn from the unique, sophisticated, multilayered practices of top designers, and from insights that have emerged from fifty years of design research. Dorst describes the nine steps of the frame creation process and illustrates their application to real-world problems with a series of varied case studies. He maps innovative solutions that include rethinking a store layout so retail spaces encourage purchasing rather than stealing, applying the frame of a music festival to understand late-night problems of crime and congestion in a club district, and creative ways to attract young employees to a temporary staffing agency. Dorst provides tools and methods for implementing frame creation, offering not so much a how-to manual as a do-it-yourself handbook—a guide that will help practitioners develop their own approaches to problem-solving and creating innovation. | https://www.ebooks-tva.org/file/frame-innovation/ |
We offer two 2-year graduate programs in Design at NCUT: Master of Design, and Master of Engineering in Design. Both of the majors share the same purpose of satisfying students’ personal needs of creative development.
We place emphasis on individual masters research project which allows student to develop independent thinking and to explore preferred discipline of design.
Main research fields of our department are as follows: visual communication, environmental design, urban planning, landscape architecture, product design, fashion design, and animation.
Our program focuses on studio-based courses, where students work on real-world projects improving analytical thinking, creativity and problem-solving abilities.
Program objectives
Our goal is to support students on their individual paths of artistic growth by sharing knowledge and creating an engaging environment to encourage inspirations and enhance creativity. After completing our program, students obtain advanced design skills and educational background essential for a successful future design careers.
Program plan
The first year expands students understanding of modern design within the context of recent technological advances, new materials, and contemporary architecture and urban design problems. Besides academic lectures, the program offers intensive studio-based training which aims in mastering practical skills of design and boosting critical thinking.
During the second year students are working independently on their graduation projects. After choosing a research subject, a student is assigned a supervisor who provides guidance and advice throughout the research process. To earn a Master’s degree student has to conduct a research, write thesis and present her/his findings during master’s defense.
Courses characteristics
We offer a variety of courses to provide students with a comprehensive understanding of the design process. Studio-based training is the significant part of our program. Students are carrying out independent and teamwork projects, which allows them to master technical design skills and to enhance communication skills. They learn how to express the design intent effectively, but also how to give a constructive feedback. Working on projects boosts critical thinking and students gain abilities of how to address design problems and come up with innovative solutions.
Our lectures equip students with the knowledge critical to the 21st century designers and researchers by introducing new technologies and materials in design.
Learning environment
We want to create a thriving and supportive learning culture in an engaging environment where students feel connected to teachers, staff and other students. Students will have an opportunity not only to learn, but be part of a positive community where they can collaboratively feel valued and have a constant opportunity to grow. We organize many design related activities, during which international students cooperate with Chinese colleagues resulting in improved cross-cultural communication skills. We also provide students with opportunities to use the advanced laboratory equipment including unmanned aerial vehicles (UAVs), 3D scanners, 3D printers, and laser engraving machine to boost creativity and technical skills. | https://www.playauthor.com/info/1010/1114.html |
Presents a clear bridge between mathematics and the liberal arts Mathematics for the Liberal Arts provides a comprehensible and precise introduction to modern mathematics intertwined with the history of mathematical discoveries. The book discusses mathematical ideas in the context of the unfolding story of human thought and highlights the application of mathematics in everyday life. Divided into two parts, Mathematics for the Liberal Arts first traces the history of mathematics from the ancient world to the Middle Ages, then moves on to the Renaissance and finishes with the development of modern mathematics. In the second part, the book explores major topics of calculus and number theory, including problem-solving techniques and real-world applications. This book emphasizes learning through doing, presents a practical approach, and features: A detailed explanation of why mathematical principles are true and how the mathematical processes work Numerous figures and diagrams as well as hundreds of worked examples and exercises, aiding readers to further visualize the presented concepts Various real-world practical applications of mathematics, including error-correcting codes and the space shuttle program Vignette biographies of renowned mathematicians Appendices with solutions to selected exercises and suggestions for further reading Mathematics for the Liberal Arts is an excellent introduction to the history and concepts of mathematics for undergraduate liberal arts students and readers in non-scientific fields wishing to gain a better understanding of mathematics and mathematical problem-solving skills.
Издательство: "John Wiley&Sons Limited"
ISBN: 9781118481646 электронная книга Купить за 7644.73 руб и скачать на Litres
ISBN: 9781118481646
электронная книга
Купить за 7644.73 руб и скачать на Litres
Другие книги схожей тематики:
|Автор||Книга||Описание||Год||Цена||Тип книги|
|Jeffrey Barton T.||Models for Life. An Introduction to Discrete Mathematical Modeling with Microsoft Office Excel||Features an authentic and engaging approach to mathematical modeling driven by real-world applications With a focus on mathematical models based on real and current data, Models for Life: An… — @John Wiley&Sons Limited, @ @ @ @ Подробнее...||9652.07||электронная книга|
|Tannenbaum Peter||Excursions in Modern Mathematics||Excursions in Modern Mathematics introduces non-math majors to the power of math by exploring applications like social choice and management science, showing that math is more than a set of formulas… — @Pearson Education (Longman), @ @- @ @ Подробнее...||2013||5303||бумажная книга|
См. также в других словарях: | https://books.academic.ru/book.nsf/88056649/Mathematics+for+the+Liberal+Arts |
Read on to find out more about the problems that need to be solved, from issues in the world to local issues that students are savvy enough to weigh in on.
Read on to find out more about the problems that need to be solved, from issues in the world to local issues that students are savvy enough to weigh in on.
While many teachers are familiar with setting their students hypothetical or fantasy issues to solve, whether as part of critical thinking or even just a math assessment, very few educators push their students to look at the real world. Some of that is instinct – we want to shelter children from the worst things happening in the world. But with the rise of the internet and information available to the average student around the clock, most children already have awareness about these issues, even if they don’t fully understand them. We look at some real-world problems students can solve as part of their classwork, engaging them in real-life, essential topics they should be educated on.
Given a little direction and all the information, students can form opinions based on their thoughts and feelings – rather than what the news or the older people around them teach them.
There are many reasons why using real-world issues in class is a part of learning about culture, responsibility, and the world around us. Many students leave education sheltered from what is going on in the world. From politics to ecology, global climate issues, and mental health issues. Educating students and allowing them to collaborate on real-world problems that need solving provides them with a basis for their own opinions and actions on problems that need solving, with issues in the world that genuinely affect and impact them.
If you’re planning on implementing real-world learning and insights into your curriculum and lesson planning, then it’s important to consider and put into place the following:
For some students, discussing specific topics can be personal and distressing. It’s essential to consider this factor before beginning lesson planning. It should also be made clear that you, as the teacher, are there to provide support – and if someone feels they cannot contribute to a class discussion, there is no problem. This is especially true for more ‘hot’ topics, surrounding subject matter relating to culture, people, and even mental and physical health. Edutopia suggests making sure that the topics covered are appropriate for the age and interests of students for the best results.
Once you’ve got that support and structured plan into place, it’s possible for lessons on real-world problems, as well as assignments, to be incredibly successful. Particularly for high schoolers, but for younger students too, providing the opportunity to speak about important matters and use their voice is vital, according to Getting Smart.
Once you’ve got the framework for your lesson, you can then consider what topics you’d like to discuss and research with your class. There is a vast range of different subject matters, some more controversial than others. It’s all about striking a balance between finding something that is interesting and engaging without being too overwhelming or stressful for your class. As a teacher, you’re best placed to know which topics suit the maturity and capacity of your students, allowing you to make an informed decision.
To start you off, here are just a few of the topics you might consider covering in your lesson plan:
Physical and mental healthcare is an excellent place to start as a topic that your students have likely heard their parents talking about regularly. With plenty of research available for healthcare access, cost, and quality, the US has a unique healthcare system unlike any other place in the world. Students could even compare current American standards versus those in other countries, such as Japan, the UK, or Europe, to compare and contrast which solution they think is best for their future and country.
Mental health, in particular, can be a difficult topic but is worth examining with your students. In the last twenty years, we’ve had more advancements on this topic than ever. Students are more aware of mental health issues and what causes them, making it an excellent subject for discussion with older classes surrounding how mental health is managed in the US and how it was handled in the past.
‘Global Warming’ has long been a topic at the forefront of the future of our planet, with scientists and regular people knowing more about the impact of this environmental issue than ever before. Your students likely have heard of climate change, making it a great starting point for discussion. There’s also ample research to cover all topics and plenty of teaching resources for your class.
Climate change, as a subject, makes for creative and innovative problem-solving. You could ask students to solve the problem if they had unlimited money and then ask them to see how they would try to fix the issue with no money but a large online following. Approaching the problem differently is an excellent way to flex those critical thinking skills and encourage students to take various approaches to solve large-scale issues.
Another topic that requires some real thought, insight, and research, housing and homelessness is a subject matter suitable for students of many age groups, depending on how you teach it. Provide your class with plenty of information and resources for their research, from the rate of homelessness in America to the issues that may lead to someone becoming homeless. For older students, you could even focus on more money-related topics such as debt and illness, which may lead to homelessness.
This topic can be emotional, but it is worth exploring with your students as a way to examine events and situations that may affect people they see around them. Many children live below the poverty line in America, which means that they most likely have been in positions where parents or guardians have struggled to keep a roof above their heads. Ask students to provide their opinion on solving homelessness in their state or even locally within their town or city, and see what solutions they come up with.
Many students will have heard first or second-hand about violent actions and attacks in America, whether they are local events or nationwide news stories about serious incidents. While this topic can be a delicate one to approach, it’s one that many young people care about – and are passionate about solving or finding a solution to. In a lesson on this subject, students should be able to access resources from many different sources, from local news articles to charity sites, online campaigns, and more.
Once students have researched these topics, consider having a whole-class discussion and making a list of solutions that could help resolve violence. Give each student a chance to speak, or in a less-vocal class, consider creating worksheets to cover this subject matter. With such a charged topic, it’s crucial to make it clear that discussion is voluntary and that, as your teacher, you are free to provide support if needed.
For impactful discussions, critical thinking, and problem-solving, tapping into real-world issues and problems can be a fantastic way to get your class engaged in the subject matter and inspired to find their voice. Students are the future – and as such, it’s just as vital for them to have an opinion, know the facts and understand how to research and learn about topics as it is to discuss those important problems in class.
Do you use real-world problem-solving in your classroom? What topics have you had the most success with? | https://classful.com/real-world-problems-students-can-solve/ |
Cyber-attacks have become so prevalent that it’s no longer a matter of if a business will be attacked but when. According to a Clark School study at the University of Maryland, a hacker attack occurs every 39 seconds, with 43% of cyber attacks targeting small businesses. 64% of all businesses have experienced a web-based attack at some point, while 31% of businesses are experiencing data loss as a result of “a lack of cyber resilience preparedness.” No company is too big, too small, or too safe to avoid attacks altogether.
Many organizations have renewed their focus on cybersecurity to prevent malicious activity and breaches, but in the face of this near-constant state of attack, it’s clear that mitigation and recovery also need to form part of every business’s security strategy. In order to preserve business continuity, every business needs a cyber resilience strategy.
What Is Cyber Resilience?
“The five most efficient cyber defenders are: Anticipation, Education, Detection, Reaction, and Resilience. Do remember: “Cybersecurity is much more than an IT topic.”
― Stephane Nappo, VP Global CISO
Cyber resilience refers to an organization’s ability to mitigate the damage to its systems, processes, or reputation and carry on with business following a security incident or data breach, or other events that may have compromised their systems. This can cover incidents caused by hackers or other malicious actors, as well as simple human errors and non-adversarial threats. You could think of cyber resilience as a form of digital fortitude that maintains end-to-end protection and readiness against any threat or data loss.
Cyber resilience has come into focus as traditional security measures are no longer enough to guarantee that networks and data will remain secure against every security event. Many IT teams now operate on the assumption that attacks will eventually gain unauthorized access to their organization at some point and prepare accordingly.
What Is The Difference Between Cyber Resilience and Cybersecurity?
The terms cyber resilience and cybersecurity are sometimes used interchangeably, but they are entirely separate concepts. Cybersecurity refers to methods and processes used to protect digital data, including all business practices and technology designed to protect it. Cyber resilience, on the other hand, refers to the ability an organization has to withstand or even recover following a disruptive cyber event, such as a denial-of-service or ransomware attack.
No cybersecurity tool or strategy is 100% flawless or impenetrable. Cybersecurity minimizes the risk of a successful cyberattack, but if it does occur, having a cyber resilience strategy in place will minimize the actual impact.
Considering that 76% of all organizations have suffered some form of downtime and data loss due to human error, cyberattacks, and system crash in 2021 and that one single minute of downtime could cost a company as much as $5,600 depending on their industry, it’s imperative that companies have a plan in place to ensure that they remain operational even in the wake of a serious breach or attack.
Why Does Cyber Resilience Matter?
Cyber attacks like Denial of Service and Ransomware attacks are designed to cause havoc and operational shutdowns. While preventing an attack is vital, identifying, managing, and mitigating the damage caused is equally important as it enables quick recovery and sustained business operations during a crisis.
Some of the benefits of cyber resilience include:
-
Minimizing Financial Losses. Cybercrime will cost the world economy $10.5 trillion by 2025. Cyber resilient organizations are able to remain operational, limiting the financial impact and monetary losses in the event of a hack or breach.
-
Mitigation of Reputational Loss. An attacked firm will lose an average of 1.1% of its market value and a 3.2% point drop in YoY sales growth. A firm’s ability to remain operational during a crisis demonstrates its trustworthiness and can go a long way to containing and reducing the fallout following a data loss or security breach.
-
Improved Security. Cyber resilience complements a robust cybersecurity program, improving an organization’s ability to eliminate threats, identify its most vulnerable data repositories and business functions, and create an incident response plan that minimizes the impact of cyber threats.
What Does Cyber Resilience Look Like in Practice?
There’s no right or wrong way to approach cyber resilience. A cyber resilience consultant will typically work with an organization to determine where operations are dependent on technology, where the most sensitive/valuable data is stored and used, and where security incidents will have the most damaging impact on the business. This helps paint a picture of the ways continuity of service will be affected in the event of an attack.
Once the impact has been understood, a mitigation and recovery strategy can be put in place, e.g., offline processes to keep essential functions running until a breach is contained and a cyber incident response plan to clarify how to respond to a failure or breach, how to communicate the incident to stakeholders, and how to report the incident to regulators (if relevant). Cyber resilience also places special emphasis on data recovery in the event of an accidental or intentional data loss, as it is impossible to ensure that data is completely protected, even with back-ups in place – thus encouraging organizations to plan for its loss and recovery.
The consultancy will also work with the organization to create a response team responsible for the execution of the incident response plan, from declaring an emergency to coordinating the organization’s response.
Conclusion
Digital transformation and technology have unlocked a myriad of business advantages, but it has also created a nearly unprecedented slew of cyberthreats. True cyber resilience requires experience and an investment in both resources and time, but considering the impact that a cyber attack or data loss can have on the bottom line of any modern organization, it’s an investment that few businesses can afford not to make. | https://www.disruptiveinnovations.net/2022/07/01/what-is-cyber-resilience-and-why-is-it-important/ |
The National Institute for Standards in Technology (NIST) is perhaps best known for establishing rigorous and robust standards for cybersecurity through the NIST Cybersecurity Framework (NIST CSF). In August 2012 they released the Computer Security Incident Handling Guide 800-61 Revision 2; while NIST is not a regulatory entity, their research into cybersecurity planning and risk management has led them to develop rigorous protocol for recording, reporting, and responding to breaches and incidents. Read on to learn how you can follow the NIST incident response guidelines to lower costs, avoid liability, and keep your clients’ data secure.
What Is NIST Incident Response?
NIST released the second revision of their Computer Security Incident Handling Guide in 2012, which treats the phrase “incident response” as interchangeable with “cybersecurity incident response.” An incident response is a systematic process that an organization can use to predict, plan for, and, per its title, handle a cybersecurity incident. The process is also iterative, in that actually encountering cybersecurity incidents will strengthen the process and help to tighten systems and avoid further incidents in the future.
The NIST guide is comprehensive and includes a checklist to prepare for security events that can be used as you build your own audit checklist. The 2012 update to the Cybersecurity Incident Handling Guide also offered an extended section on how to share information between organizations in the case of a cybersecurity threat.
Why Is NIST Providing Recommendations on Incident Response?
NIST developed its guidelines on incident response in an effort to help federal agencies, businesses, and non-governmental organizations prepare for cybersecurity incidents; the guidelines are designed to help organizations respond to incidents as quickly as possible.
Under the Federal Information Security Modernization Act(FISMA), NIST is obligated to provide recommendations to Federal agencies, as these agencies are required to demonstrate their incident response capability. In certain cases, organizations are required to report incidents; for example, under FISMA, or the Health Insurance Portability and Accountability Act’s (HIPAA) “Breach Notification Rule”. In the 2012 revision, NIST’s guidelines offered a more robust section on how to share information about a cybersecurity incident across organizations to help prevent further damage and fallout from the event.
What Does the NIST Incident Response Cycle Look Like?
NIST’s incident response cycle has four overarching and interconnected stages: 1) preparation for a cybersecurity incident, 2) detection and analysis of a security incident, 3) containment, eradication, and recovery, and 4) post-incident analysis.
However, NIST is intentional in its use of the term “cycle”; the response cycle is iterative and feedback driven, and they are clear that incident response is a practice that is ongoing, not merely a reaction to an event which ultimately resolves. Preparation includes an active risk assessment plan, and post-incident analysis includes learning and preparation for the next set of potential incidents.
The Four Parts of the NIST Incident Response Cycle
1. Preparation
Preparation for an incident can be daunting when you haven’t already encountered the threat and don’t yet know the full shape of it; one of the key challenges of risk assessment is preparing for the unknown. In preparing for a cybersecurity incident, NIST suggests implementing a series of tools ahead of time, so that you are ready to analyze, isolate, and respond to an incident. These include securing communication tools and facilities for anyone who will be handling incidents if they occur, from having contact information readily available for stakeholders and reporting entities, to purchasing smartphones for your Computer Security Incident Response Team (CSIRT), to having space available for your “war room” where the team can gather and manage the crisis.
The guidelines also suggest ensuring you have up-to-date hardware and software ready for incident analysis; while the document does not cover exactly how to secure systems, it offers broad strokes advice on conducting risk analyses and securing your systems to best prevent an incident from occurring, but the details will be industry-specific.
2. Detection and Analysis
The detection and analysis stage requires first identifying the type of threat you’re facing. NIST provides a list of potential threat types and divides the signs of an incident into two categories: precursors and indicators.
A precursor is a sign that an incident may occur in the future, and an indicator is a sign that an incident may be occurring at present or have already occurred. Unfortunately, most signs of an attack are only visible after an attack has already begun, but an organization with a mature incident response capability may be able to detect precursors and prevent an attack before it begins.
You will likely be dealing with indicators; these will guide you in determining where the attack is coming from, how to contain it, and how long you have to continue to gather evidence. After the incident has been identified and detected, this phase includes everything from analyzing security weaknesses, to prioritizing post-incident actions, measuring the impact, properly documenting the incident, and finally notifying impacted parties. This part of the cycle also includes properly reporting a cybersecurity incident to the appropriate agencies, law enforcement, and other affected parties.
3. Containment, Eradication, and Recovery
Containment, eradication, and recovery make up the bulk of the active incident response. This stage of the incident response includes isolating the threat, to make sure it does not grow; however, NIST documentation is clear that the containment strategy must match the type of attack and the potential damage incurred if the attack continues. Moreover, merely disconnecting the attacking host from the data source may backfire; NIST suggests that the incident response team has a specific containment plan for each type of attack they anticipate based on risk assessments and analyses. This phase includes identifying and researching the attacking host and gathering evidence that can be used in legal matters; NIST suggests that in some cases the response team may choose to use a “sandbox” to contain the threat, to encourage the attack to continue so the team can gather more data, but a delayed full containment may lead to more damages if applied in the wrong context.
Once contained, your cybersecurity team can work on eradicating the threat, including removing malware and deleting compromised accounts. Finally, the team can move to a phased recovery, where the organization can resume with normal operations; recovery may include cybersecurity patches and taking steps to improve firewalls, reinstall anti-malware, restore systems from clean backups, and changing passwords across the organization.
4. Post-Incident Activity
NIST says that this step is the most often omitted and the most important — after the incident, the team should hold a “Lessons Learned” meeting to process the incident, go over strategies for preserving the data collected and evidence gathered over the course of the meeting, and revisit preparation for future projected cybersecurity threats. This phase also includes creating a follow-up report on every part of the incident. This report can be used for internal purposes, and can also be shared with external organizations; managing and preventing cybersecurity threats often goes beyond a single organization and requires cooperation and mutual involvement across the entire incident response cycle.
Do You Need a NIST Incident Response Team?
The NIST recommends having a Computer Security Incident Response Team, either in-house or through a third-party Information Sharing and Analysis Center (ISAC); this team will include IT and cybersecurity experts, but may also engage public relations and legal experts. Depending on the scale and cybersecurity needs of your organization, you may choose to hire professionals to be available immediately and onsite; if your organization has overwhelming security needs, like Facebook or Amazon, then your team will be full-time and available 24-7. But for many organizations, hiring full-time IT staff to respond to incidents is not particularly cost-effective. The UK’s National Cyber Security Centre states that “it is more cost effective to have a ‘virtual’ CSIRT, pulled together when needed, from people who have other day jobs.” The NIST states that organizations which do not have contact with a CSIRT “can report incidents to other organizations, including Information Sharing and Analysis Centers (ISACs)… industry-specific private sector groups [which] share important computer security-related information among their members.”
NIST Incident Response Takeaways
NIST’s strategies for incident response and their vision for the incident response cycle are some of the best available for IT management teams and CIOs seeking to protect their organization from costly, reputation-damaging cybersecurity events and figuring out how to prevent cybersecurity breaches. NIST argues that incidents are just part of the IT landscape, we may not be able to avoid them entirely, but we can certainly minimize their impact on our businesses and lives. If your team wants to be prepared for a potential cybersecurity event, AuditBoard’s compliance management software can help you keep track of NIST’s incident response guidelines and ensure that you’re checking off all of the most important items on their list and that you have a central hub for your CSIRT to access relevant documentation, logs, and incident-related information. | https://www.auditboard.com/blog/nist-incident-response/ |
What Is an Incident Management Plan?
An incident management plan is also known as an incident response plan or emergency management plan. It is a business document that aids an organization to return to its normal operations as soon as possible, following an unforeseen event. The incident management plan also recognizes possible weaknesses in the system, mitigates the impact of various situations, and limits the effect on the reputation, operations, and financial capacity of the organization. With the increase in several security issues at present, including ransomware attacks and data breaches, organizations must ensure they have a system to mitigate and recover from these situations. Instead of waiting for these occurrences to happen, companies must be proactive and secure an incident management plan. The plan serves as a break or make point of the company when it comes to response effectiveness. Incident management can also be part of a larger planning document like the overall business continuity management plan. Services restoration depends on the impact and severity of the event with temporary solutions. Generally, the use of the incident management plan focuses on recognizing an incident, assessing a situation, notifying affected individuals or departments, organizing and mobilizing response techniques and resources, and documenting the recovery process.
According to the information from Securelist entitled Incident Response Analyst Report 2019, victims of incidents show that less than a quarter of received requests are false positives, mostly suspicious files or activities in systems. True positive requests include the discovery of suspicious and encrypted files and alerts from security tools. Most incidents happen in the Middle East at 32.6 percent, the European Union at 24 percent, and the Commonwealth of Independent States at 21.7 percent.
Components of an Incident Management Plan
An incident management plan is a vital document in ensuring that a company can function after an unforeseeable event. The contents of the plan must communicate the necessary responses the organization must perform to make sure that operations can continue as soon as possible. Below are the essential elements that the incident management plan must contain.
How to Develop an Incident Management Plan
In terms of cyber security, the goal of the incident management plan is to address detected data breaches using different phases. In each phase of the plan, the members of the incident management team must consider and perform to find possible solutions. Below are the phases to follow when developing the incident management plan.
1. Preparation Phase
The initial step to the incident management plan serves as the workhorse and the most crucial phase to protect the business. During the preparation phase, the organization ensures that all the employees have the proper training and knowledge about their roles and responsibilities in the event of a security breach. There must also be a development of incident response drills and possible scenarios, including the regular conduction of mock data breaches for evaluation. In the preparation phase, the organization also approves necessary budget plans for the implementation of the plan. The management plan must be well-documented, highlighting personnel duties and testing performance, to guarantee the best response.
2. Identification Phase
In the identification phase, the incident management team determines whether there is an event of security or data breach, and it can originate from different areas. In this step, the team members must identify the time of occurrence, method of discovery, the person responsible, impacted areas, the scope of the compromise, operational implications, and the point of entry.
3. Containment Phase
At the initial discovery of a breach, the initial response is to delete it. However, it will affect the company in the long run for destroying valuable evidence to determine the source of the breach, and from there, develop a plan to prevent its reoccurrence. Contain the breach to prevent its spread to different systems and cause further damage to the organization. Try disconnecting devices from the internet, and prepare to perform short-term or long-term containment strategies. Setting up system backups also helps with restoring business operations. It is advantageous to perform system updates and patches, scan remote access protocols, modify user and administrative access credentials, and strengthen password lists.
4. Eradication Phase
After the containment process, the next step is to detect and destroy the root cause of the breach. As a result, begin securely removing all malware, patch and harden all systems, and apply the necessary updates. The company has the option of hiring a third-party specialist to perform the steps thoroughly. If there are malware or security issues that remain in the systems, there is still the risk of losing data, decreasing liabilities.
5. Recovery Phase
In this step, responsible personnel takes the time to restore and return affected systems and devices and incorporate them back to business operations. At this time, take the necessary steps to get the company running once again without the fear of running into another breach. It is also advisable to keep monitoring systems and devices and prepare the necessary tools to counter any reoccurrence of attacks.
6. Lessons Learned
After the overall incident investigation, hold a post-incident meeting with the incident management team members and discuss all necessary information and learnings from the event. This step allows the company to analyze and record details about the breach. The team then determines the processes and techniques that were successful and indicates any possible holes in the system. This step helps strengthen the future responses to future attacks.
FAQs
What are the five stages of the incident management process?
The five steps of incident resolution include incident identification and categorization, incident notification and escalation, incident diagnosis and investigation, resolution and recovery, and closure.
What is the KPI for incident management?
Key performance indicators are measurement tools that aids organizations to determine whether they are reaching their business goals. In terms of incident management, the necessary metrics that must be present include the number of incidents, resolution time, and the average time between each incident.
What is an IR plan?
An IR plan or an incident response plan is more common terminology for the incident management plan. It details pre-determined instructions and processes to detect, respond to, and limit possible data breaches in organizational systems.
Every organization must ensure the safety of its resources, especially those that are within systems. It is better to be proactive than reactive when it comes to handling security breaches in the business. As early as possible, prepare possible mitigation methods and processes to help the organization at the possibility of unforeseen events. Design your incident management plan by downloading the samples available in the article, and ensure that your company is ready for any incident that comes your way. | https://www.sample.net/business/plans/incident-management-plan/ |
In the event of a cybersecurity breach, it is important to identify critical next steps and minimize the disruption created by the incident. Our cyber incident reponse (IR) team can be deployed in less than 24 hours to coordinate response management, begin containment, assess damage and facilitate the remediation and recovery process.
We will develop a comprehensive cyber incident response plan to contain the incident, eradicate the cause and recover operations. This plan is continuously updated throughout the engagement so that key stakeholders understand what systems were impacted and have the insight into availability, estimated recovery time and overall response progress.
Our cyber incident response process involves:
-
Containment Guidance - The first step in our approach is to identify attacker activity and determine an appropriate containment strategy. We will deploy technology that will scan the environment for indicators of compromise and will provide continuous monitoring to validate recovery of systems as we move through the containment process. Our main goals are to determine the operational status of infected systems and protect the integrity and availability of critical computing resources where possible.
-
Damage Assessment - Once the cyber incident has been contained, we will conduct a damage assessment investigation to identify and evaluate impacted systems and applications and define the effect the breach had on the organization. During this investigation, we will identify what data was accessed, who was responsible and the extent to which the attack was successful or unsuccessful. This information will be critical for crafting appropriate communications to internal and external parties such as clients, customers and regulatory authorities.
-
Recovery - The recovery stage is the process of restoring and returning affected systems and devices back into your business environment. During this time, it’s important to get systems and business operations up and running again without the fear of another breach. Our IR team will help to decide when operations will be restored, test and verify that infected systems are fully restored, continue to monitor for malicious activity, and validate recovery.
-
Remediation - Eradication is the first step in the remediation process. We will systematically remove the issue from your systems. In addition, we will present a plan of action to mediate and close security gaps identified during the incident response. Our team will work with management to coordinate system restoration using existing corporate contingency plans and can recommend revisions or enhancements to future incident response activities.
-
Post Incident Activity - Lastly, our IR team will assist in finalizing documentation from the incident investigation and remediation and supply a detailed report reviewing the entire incident response process. During this phase, the team gleans insights from the IR process to improve steps in each phase for the future. A meeting can be conducted to debrief and cover the scope of the incident. The IR team may also provide recommendations for improvement in the IR process and how the threat can be contained and eradicated in the future.
Rapid cyber incident response is critical to the safety and success of your organization. DataSure24 has over 15 years of experience serving clients’ technology needs and is SSAE-18 certified and TIA-942 compliant.
Are you looking for a Buffalo managed cybersecurity firm to handle rapid cybersecurity incident response? Simply fill out the form at the bottom of this page and one of our professionals will be in touch. | https://www.datasure24.com/rapid-incident-response |
How do you respond to a security breach?
3. Communication
- Contain the breach.
- Assemble the response team.
- Investigate the breach.
- Document the who, what, where, when, why and how of the breach as well as the relevant notification time limits.
- Follow your breach communication procedures including informing authorities, insurance companies and affected parties.
How would you respond to a data breach in the workplace?
72 hours – how to respond to a personal data breach
- Step one: Don’t panic. …
- Step two: Start the timer. …
- Step three: Find out what’s happened. …
- Step four: Try to contain the breach. …
- Step five: Assess the risk. …
- Step six: If necessary, act to protect those affected. …
- Step seven: Submit your report (if needed)
How do you respond to a cyber incident?
Cyber incident response steps
Investigate whether a problem has occurred. Talk with staff and review logs to determine whether a compromise has occurred. Fix the problem. Remove any viruses from your networks, or close identified gaps in your network.
What should be reported as a data security incident?
Computer system breach. Unauthorized access to, or use of, systems, software, or data. Unauthorized changes to systems, software, or data. Loss or theft of equipment storing institutional data.
How do you handle data breaches?
How to Effectively Manage a Data Breach
- 5 Steps to Protect Your Organization After a Data Breach. …
- Start Your Incident Response Plan. …
- Preserve Evidence. …
- Contain the Breach. …
- Start Incident Response Management. …
- Investigate, Fix Your Systems, And Implement Your Breach Protection Services.
What is a data breach response plan?
The plan sets out contact details for the appropriate staff in the event of a data breach, clarifies the roles and responsibilities of staff, and documents processes to assist the OAIC to respond to a data breach. …
How do you investigate a data breach?
7 steps for responding to and investigating a data breach
- Detect the data breach. …
- Take urgent incident response actions. …
- Gather evidence. …
- Analyze the data breach. …
- Take containment, eradication, and recovery measures. …
- Notify related parties. …
- Conduct post-incident activities.
What are the six steps in the incident response methodology?
An effective cyber incident response plan has 6 phases, namely, Preparation, Identification, Containment, Eradication, Recovery and Lessons Learned. | https://fascofl.org/in-reality/how-do-you-respond-to-a-data-security-incident.html |
Cybersecurity incident response is a critical aspect of protecting an organization’s assets and reputation. A well-planned and executed incident response plan can mean the difference between a minor disruption and a major catastrophe. In this post, we will discuss the importance of incident response planning, the key components of an incident response plan, and the steps involved in responding to a cybersecurity incident.
First, let’s talk about why incident response planning is so important. Cyberattacks are becoming increasingly common, and the consequences of a successful attack can be devastating. Data breaches can result in the loss of sensitive information, financial losses, and damage to an organization’s reputation. In addition, the cost of responding to a cyber incident can be significant, and it’s important to have a plan in place to minimize the impact of an attack.
An incident response plan should include several key components. First, it should identify the types of incidents that the organization is most likely to face. This includes things like data breaches, network intrusions, and denial of service attacks. The plan should also specify the roles and responsibilities of various team members, including incident responders, IT staff, and management. Additionally, the plan should include procedures for communication, both within the organization and with external parties such as law enforcement or regulatory agencies.
When an incident occurs, the first step is to contain the damage. This involves taking steps to stop the attack from spreading and to prevent further data loss. This may include disconnecting affected systems from the network or shutting down services. Next, the incident response team will investigate the incident to determine the cause and extent of the attack. This may involve analyzing system logs, network traffic, and other data.
Once the incident has been contained and investigated, the incident response team will work to eradicate the attack. This may involve removing malware or patching vulnerabilities. It’s also important to implement measures to prevent the same incident from happening again in the future. This may include implementing new security controls, such as firewalls or intrusion detection systems, or reviewing and updating security policies.
Finally, the incident response team will work to recover normal operations. This may involve restoring systems and data, and communicating with users and other stakeholders about the incident. The incident response plan should include procedures for documenting the incident, including what was done to respond to it and what was learned from the experience.
In conclusion, incident response planning is an essential aspect of cybersecurity. A well-executed incident response plan can help minimize the impact of a cyber attack and get the organization back to normal operations as quickly as possible. It’s important to regularly review and update incident response plans to ensure they are effective in the event of a cybersecurity incident. Additionally, it’s important to regularly train employees on incident response procedures, so they are prepared to respond quickly and effectively in the event of an incident. Give us a call at 269-201-2011 or e-mail us at [email protected] today to have our team of experts to review your current incident response plan or help you draft a new one. | https://cyberlakesecurity.com/incident-response-plan/ |
Business of all sizes and types are being tested in unprecedented ways by the coronavirus (COVID-19) pandemic. Business continuity and an organization’s operational resilience has become top of mind in boardrooms and C-suites across the world. Protiviti’s Business Continuity Management (BCM) experts are helping CIOs, CISOs, CROs, CFOs as well as other executives such as HR and marketing revisit their business continuity planning (BCP) and evaluate how to implement BCP practices into day-to-day activities.
We recommend these resources:
- Resource: Top 15 Questions: A Guide to Business Continuity Management FAQ
- Blog: Going Back to the Office: Determining Key Personnel Risk in a New Reality
- Blog: So You Had a Plan… Resetting the Technology Portfolio to Align With the Reemergence Strategy
- Webinar Replay: Responding to Operational Disruptions due to COVID-19
What is Business Continuity Management?
Business Continuity Management (BCM ) is the design, development, implementation and maintenance of strategies, teams, plans and actions that provide protection over, or alternative modes of operation for, those activities or business processes which, if they were to be interrupted, might bring about seriously damaging or potentially significant loss to an enterprise. All sectors and sizes of companies can benefit from a BCM program. An Operational Resilience program can enhance and extend traditional BCM practices and concepts by incorporating various approaches such as testing extreme-but-plausible scenarios, front-to-back process mapping and aligning all aspects of cyber, third-party and technology resilience, as illustrated in Protiviti’s Operational Resilience framework.
When creating a continuity plan, organizations should consider the three core disciplines of traditional business continuity management:
- Crisis management and communications – This discipline enables an effective and cohesive response to an event. Crisis management processes focus on stabilizing the situation and supporting the business if alternate modes of operation are needed, using effective planning, leadership, and communication protocols.
- Business resumption planning – This discipline focuses on disrupted aspects of business functions and processes that relate to or support the delivery of core products or services to a customer. Business resumption processes focus on the evaluation of people, processes, technology, and other resources that are vital to the organization's operations. The objective of business resumption planning is to mitigate potential impacts from disruptions, regardless of the cause, by developing plans that guide personnel through operations with diminished capabilities and toward business as usual (BAU).
- IT disaster recovery (ITDR) – This discipline addresses the restoration of critical information technology assets, including systems, applications, databases, storage, and network assets. An ITDR strategy should encompass all technology service provider relationships (e.g., cloud providers) to ensure all technical stakeholders remain aligned.
In addition to the traditional BCM disciplines listed above, there are other closely related programs that many organizations manage as part of their overall BCM program. These programs include:
- Incident management (or incident response) – This term commonly refers to the process of identifying, analyzing and managing the response to a disruptive event. Regardless of the nomenclature used, incident management programs typically include emergency response measures such as the evacuation of facilities, first aid response and first-responder interactions.
- Cybersecurity incident response – This is specific to the planning for, response to, and recovery from a cybersecurity incident such as a data breach, phishing attempt or distributed denial of service (DDoS) attack.
Why is Business Continuity Management Important?
The value of Business Continuity Management lies in risk mitigation — minimizing the risks associated with any disruption to business as usual. Having a continuity plan allows organizations to respond to risks that not only impact business operations but also provides the ability to protect their people and brand, earn revenue, maintain relevance and remain compliant with regulations. Companies need to stay ahead of these risks by understanding priorities, planning for disruptions, employing good business practices, and exercising forethought to increase their ability to course-correct quickly when things go wrong.
How Protiviti Helps Clients
No one can predict when the next disaster or business disruption will strike; the only certainty is that something unplanned and disruptive will happen. Protiviti is helping companies prepare and build resilience for the unknown, manage risk and develop sustainable business continuity programs. Our services support your on-going BCM lifecycle planning and management process.
- BCM Program Assessment & Reviews
- Crisis Management Plan
- Incident Response Plans
- Business Resumption Plans
- IT Disaster Recovery Plan
- Program Maturity Assessment
- Business Impact Analysis
- Assess various impacts of a business interruption on key business processes
- Determine business processes’ criticality, recovery objectives and reliance on business applications and 3rd parties
- Continuity Risk Assessment
- Assess various impacts of a business interruption on key business processes
- Determine business processes’ criticality, recovery objectives and reliance on business applications
- Identify business continuity related risks to the organization
- Determine likelihood, significance, and velocity of business impact from a continuity perspective
- BCM Strategy Development and Implementation
- Develop recovery strategies designed to minimize impact from an outage
- Develop and document crisis management, business resumption, and IT DR plans
- IT Disaster Recovery
- Determine, document, and implement technical recovery options for IT DR needs
- Design and execute IT DR testing
- BCM Testing and Training
- Design and facilitate business continuity or crisis management exercises
- Develop and execute BCM training for key personnel responsible for recovery activities
- Business Continuity Planning Outsourcing
- Dedicated business continuity planning personnel
- Responsible to update your plans, facilitate tests, and ensure your business continuity management plan is always actionable.
- Continuity Project Management
- Project Management personnel to guide your Business continuity plan team and objectives
- Business Continuity Management Project Management Office (PMO)
Sustainable Solutions
Flexible Delivery Capabilities with our Managed Technology Solutions
Over 2.7 million experienced professionals at Robert Half support Protiviti’s core team of Microsoft consultants, operating from over 400 offices across 25 countries. All those local professionals mean that we’ll find the specialized Microsoft skills you need fast, without on-the-job training, and minimal to no travel costs. It also means we can ramp up — or down — depending on your budget and needs.
In today’s environment of rapid digital change, growing cyber concerns and outages impacting the financial sector, operational resilience continues to be top of mind for industry executives and supervisory authorities around the world. Protiviti’s Operational Resilience framework provides a structure that can be leveraged to help understand, prevent, and recover from extreme-but-plausible events that may impact important business services. | https://www.protiviti.com/US-en/continuity-planning |
Please join us for a half-day seminar to understand key strategies for how your organization can design controls, implement critical processes and leverage technical solutions to prevent attacks. The session will cover:
1) Evaluating Your Threat Profile – Understand the kinds of assessments to perform in order to identify, validate, and provide remediation steps for any vulnerabilities in your environment that can be exploited by potential ransomware attacks. Techniques such as Red Teaming, Purple Teaming, and penetration testing can simulate real-world ransomware attacks using the latest ransomware payloads and attack vectors to identify vulnerabilities.
2) Defining Security Controls to Prevent, Detect and Respond to Attacks – This includes leveraging automated tools for detection and prevention; designing data backup and business continuity processes and solutions; understanding where your threats exist and how it evolves with technology and industry changes.
3) Know Your Data – It all comes down to understanding where your data is stored, how it’s used, and how it may be vulnerable to ransomware attacks. Including how to perform a data mapping exercise to document where each data element is stored, who has access to it, where it comes from, how it flows through your organization, and who it is shared with. And how to perform a privacy impact assessment to understand where your sensitive information is stored, how it is used, and what security controls are in place to protect it.
4) Implementing a “Zero Trust” Architecture – Understand how to implement a Zero Trust architecture to strengthen your defenses against ransomware and other external attacks. With this approach, every device or person accessing a company resource is verified, regardless of whether they are inside or outside the in-house network perimeter. This broad concept includes elements such as multi-factor authentication (MFA), granular network segmentation, and “least privilege” access rights and privileges.
5) Incident Response Plan Best Practices – Tips for developing and implementing an incident response plan that identifies the people, processes, communications plans, technical solutions, and other resources that will be deployed to detect and respond to ransomware attacks. Key skills the team(s) should have including ransomware detection and analysis, emergency incident response management, communication with criminal ransomware organizations, ransomware eradication, and restoration of normal operating environments. | https://engage.isaca.org/newjerseychapter/events/eventdescription?CalendarEventKey=4ce11309-f838-4d60-8258-4bd00d34fbbb&CommunityKey=3de06995-136a-4983-8ad6-433ba10225ff&Home=%2Fevents%2Fcalendar |
Based on three years (2016-2018) of cyber incident response plan assessments and data breach simulations conducted by Verizon for its customers, the new Verizon Incident Preparedness and Response (VIPR) Report gives organizations strategic guidance on creating effective and efficient incident response plans.
“Companies think that having an incident response plan on file means they are prepared for a cyber attack. But often these plans haven’t been touched, updated or practiced in years and are not cyber-incident ready,” comments Bryan Sartin, Executive Director, Verizon Global Security Services. “Having an out-of-date plan is just as bad as having no plan at all. Incident response plans need to be treated as ‘living documents’, regularly updated, and breach scenarios practiced in order for them to be truly effective.”
Verizon experts have identified the six typical phases that every incident response plan should contain:
- Planning and preparation – this includes constructing the incident response plan to include key internal stakeholders and third parties - crucial for an effective response.
- Detection and validation – detect and classify cyber-security incidents by severity level and source early in the incident response process.
- Containment and eradication – focus on containing and eradicating cyber-security threats.
- Collection and analysis – collect and analyse evidence organisations to shed further light on cyber-security incidents; helping with effective data breach containment, eradication, remediation and recovery activities.
- Remediation and recovery – provide remediation and recovery measures; specifically, describe those actions to not only ensure operations are recovered and restored to normal but to also prevent or mitigate future incidents.
- Assessment and adjustment – feed post-incident lessons-learned results back into the incident response plan to improve cyber-security metrics, controls and practices.
The VIPR Report also includes five ‘Breach Simulation Kits’ consisting of real-world scenarios to provide organizations with the content to facilitate their own mock incident table-top exercise.
The complete Verizon Incident Preparedness Response Report is available to download on the VIPR Report resource page. | https://www.continuitycentral.com/index.php/news/business-continuity-news/4457-cyber-incidents-businesses-urged-to-be-prepared-be-proactive-and-practice-practice-practice?tmpl=component&print=1&layout=default |
By: Mark Sheldon Villanueva on October 20th, 2021
What is an Incident Response Plan?
Cyber attacks are increasing, and so are their severity and the length of time required to resolve them. An effective incident response plan can help mitigate these problems. Find out what an incident response plan is and why you need one.
What would you do if you were hit with a cyber attack? If you're not sure of your answer, then you might want to seriously consider creating a plan of action. That's because your business could be at risk regardless of its size.
The Federal Bureau of Investigation reported that cybercrime rose by 300% in 2020 alone, and almost half of those attacks were aimed at small businesses.
The number of cyberattacks hitting US organizations isn't the only thing that's been on the rise recently. Sadly, the severity of the attacks and the length of time needed to address them have also been growing.
In a study conducted by IBM, 65% of business leaders said attack severity is increasing, with 57% reporting it's taking longer to resolve cyber incidents. So what's happening there?
While it's true that cyberattacks have grown more sophisticated through the years, that is only part of it. A key driver for these alarming numbers may be the result of how businesses fail to respond to cyber threats effectively. In the same study, IBM found that a large majority (77%) of US businesses don't have a consistent cybersecurity response plan.
At ITS, we've helped hundreds of businesses improve their cybersecurity efforts. In our experience, having a plan to effectively respond to cyber incidents is vital in today's threat landscape.
In this article, we'll teach you the basics of an incident response plan to help you set one up for your business. To do that, we'll have to dive into the following:
- What is an incident response plan?
- Why do you need an incident response plan?
- 6 steps of an incident response plan
What Is an Incident Response Plan
An incident response plan is a written plan to help IT professionals identify, eliminate and recover from cybersecurity threats. It's designed to help your organization respond quickly and uniformly against any form of cyber attack.
If properly managed and updated, an incident response plan can help you minimize the damage caused by attacks like data loss, abuse of resources, and the loss of customer trust.
Why Do You Need an Incident Response Plan?
Cybercriminals want to confuse your team during an attack. It's beneficial for them. Your inability to respond appropriately can buy them the time they need to get what they want, whether it's your data or your hard-earned money. A well-thought-out plan can help reduce that confusion and give your team the right mindset to deal with any cyber incidents effectively.
Here are some of the most common advantages you can gain with an incident response plan:
Speeds Up Your Team's Response Time to Threats
When it comes to cyberattacks, time is essential. It helps minimize the damage that a malicious actor can inflict on your business.
Having a consistent incident response plan allows your team to respond immediately when an incident occurs. Relevant members of your team will also have a clear roadmap to help them identify and react to an external attack, potentially buying you the time you need to resolve the situation.
Protects Your Data
Your data is expensive. In IBM's annual Cost of a Data Breach Report this 2021, they found that data breaches cost businesses a total of $4.24 million per incident on average. That is a 10% increase over last year's total.
Data and system protection are at the core of incident response plans. When a breach occurs, your plan should immediately kick in and enable your team to respond quickly. That way, they can secure backups and deploy patches to vulnerabilities in a timely manner to help protect your data.
Reinforces Your Organization's Reputation
How a company responds to incidents is very revealing. An effective and timely response shows that your organization is committed to security and privacy. On the other hand, failing to stop an attack promptly may cast doubt on your entire operation. Customers and shareholders may even choose to do business elsewhere. Having a reliable incident response plan is critical in preventing that outcome.
Limits Damage of Breach
In many cases, attackers can attempt to disrupt your operations by encrypting your data and holding it for ransom for an indefinite period of time. The result is unplanned downtime that can seriously hurt your bottom line. According to Gartner, downtime at the low end can cost as much as $140,000 per hour, $300,000 per hour on average, and as much as $540,000 per hour at the higher end.
Having an incident response plan can limit the damage and costs of a breach by enabling your team to respond to one quickly and effectively. The faster you are able to resolve the issue, the less damage your organization is bound to incur.
4 Steps of an Incident Response Plan
An effective incident response plan can be broken down into four steps, and it's essential to create structured procedures for each one.
The four steps include:
1. Preparation
Perhaps the most vital and work-intensive step is at the preparation stage. This phase is where you will document, outline and explain your response team's roles and responsibilities. That includes establishing the underlying security policies which will guide the development of your incident response plan.
It is at this time where you can perform risk assessments to determine whether your team can handle an attack or if you would need the help of a third party. This is also the stage where you need to determine the location, sensitivity, and relative value of all your data and assets. That will help you identify critical security incidents you should focus on.
Lastly, this step is also where you assign roles for members of your response team, including a chain of command which involves your IT and corporate leadership. Ensure that they have access to relevant systems and tools so that they can respond to incidents effectively.
2. Identification
The identification stage involves the monitoring, detecting, alerting, and reporting of security events. The primary objective for this stage is identifying known and unknown threats and suspicious activity that seem malicious in nature. In this phase, the collection of log data is critical to identify how the incident occurred, its root cause, and the systems and data affected.
You need to develop a proactive detection strategy like Security Information and Event Management (SIEM) processes. That will enable your team to conduct deep analysis and forensics that can help you gather critical information regarding a security incident.
3. Response
Once a breach has been detected, containment should be your next priority to ensure that infection does not spread. Isolating compromised systems, networks, data stores, and devices can minimize the damage after an incident.
After removing adversary access, your response team should then determine the extent of damage and the potential risks it poses to your business. That should be followed by the analysis of forensic artifacts, eradication of infected files, and patching of the breach.
In this stage, your team should also ensure that data regarding the incident is logged and documented properly to help with investigations.
4. Recovery and Review
This stage is where your team can begin to analyze all relevant information regarding the incident.
Post-incident activities include:
- Reviewing and reporting on what happened.
- Updating your cybersecurity program with new information about what worked and what to improve.
- Updating your IR plan with lessons learned.
Your team should also perform a thorough cybersecurity assessment to verify your environment is truly clear of threats.
Ready to Set Up your Own Incident Response Plan?
An incident response plan is a necessity in today's current threat landscape. Make sure you develop one that provides actionable steps that can guide your team in dealing with incidents more effectively.
Want to find out where your cybersecurity measures stand? At ITS, we can help assess your environment so you can have a better idea of what you need to bolster your security efforts. Fill out our form for a free security assessment! | https://www.itsasap.com/blog/what-is-incident-response-plan |
Incident Response Readiness Service
In the event of a cybersecurity incident, we support our clients to help them throughout the incident response lifecycle - preparation, identification, containment, eradication, recovery and lessons learned.
The ISA Incident Response Readiness Service allows organizations to establish terms and conditions for incident response services before a cybersecurity incident is suspected. Having a retainer in place provides a mechanism to quickly engage with the ISA incident response team to ensure a timely response to a suspected cybersecurity incident. Further, the ISA Incident Response Readiness Service can be customized to include proactive steps to minimize cybersecurity risks and to improve your organization's overall cybersecurity posture.
Our Incident Response service offers:
- Customized Response: Incident preparedness services designed to provide a rapid and customized response to a cybersecurity incident.
- Cyber Threats Intelligence: Access to global threat intelligence information to aid in the identification and assessment of cybersecurity incidents.
- Dedicated Incident Response Team: A team focused on helping organizations prepare for and respond to cybersecurity incidents. | https://www.e-isa.com/incident-response.html |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.