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tence can be rewritten to reduce possible misinterpretation, either by adding a comma after "taxes" to convey the first sense or by changing "which" to "that" to convey the second sense or by rewriting it in other ways. The devious politician hopes that each constituent will interpret the statement in the most desirable way, and think the politician supports everyone's opinion. However, the opposite can also be truean opponent can turn a positive statement into a bad one if the speaker uses ambiguity intentionally or not. The logical fallacies of amphiboly and equivocation rely heavily on the use of ambiguous words and phrases.
In continental philosophy particularly phenomenology and existentialism, there is much greater tolerance of ambiguity, as it is generally seen as an integral part of the human condition. Martin Heidegger argued that the relation between the subject and object is ambiguous, as is the relation of mind and body, and part and whole. In Heidegger's phenomenology, Dasein is always in a mean |
ingful world, but there is always an underlying background for every instance of signification. Thus, although some things may be certain, they have little to do with Dasein's sense of care and existential anxiety, e.g., in the face of death. In calling his work Being and Nothingness an "essay in phenomenological ontology" JeanPaul Sartre follows Heidegger in defining the human essence as ambiguous, or relating fundamentally to such ambiguity. Simone de Beauvoir tries to base an ethics on Heidegger's and Sartre's writings The Ethics of Ambiguity, where she highlights the need to grapple with ambiguity "as long as there have been philosophers and they have thought, most of them have tried to mask it... And the ethics which they have proposed to their disciples has always pursued the same goal. It has been a matter of eliminating the ambiguity by making oneself pure inwardness or pure externality, by escaping from the sensible world or being engulfed by it, by yielding to eternity or enclosing oneself in the pu |
re moment." Ethics cannot be based on the authoritative certainty given by mathematics and logic, or prescribed directly from the empirical findings of science. She states "Since we do not succeed in fleeing it, let us, therefore, try to look the truth in the face. Let us try to assume our fundamental ambiguity. It is in the knowledge of the genuine conditions of our life that we must draw our strength to live and our reason for acting". Other continental philosophers suggest that concepts such as life, nature, and sex are ambiguous. Corey Anton has argued that we cannot be certain what is separate from or unified with something else language, he asserts, divides what is not, in fact, separate. Following Ernest Becker, he argues that the desire to 'authoritatively disambiguate' the world and existence has led to numerous ideologies and historical events such as genocide. On this basis, he argues that ethics must focus on 'dialectically integrating opposites' and balancing tension, rather than seeking a priori |
validation or certainty. Like the existentialists and phenomenologists, he sees the ambiguity of life as the basis of creativity.
Literature and rhetoric
In literature and rhetoric, ambiguity can be a useful tool. Groucho Marx's classic joke depends on a grammatical ambiguity for its humor, for example "Last night I shot an elephant in my pajamas. How he got in my pajamas, I'll never know". Songs and poetry often rely on ambiguous words for artistic effect, as in the song title "Don't It Make My Brown Eyes Blue" where "blue" can refer to the color, or to sadness.
In the narrative, ambiguity can be introduced in several ways motive, plot, character. F. Scott Fitzgerald uses the latter type of ambiguity with notable effect in his novel The Great Gatsby.
Mathematical notation
Mathematical notation, widely used in physics and other sciences, avoids many ambiguities compared to expression in natural language. However, for various reasons, several lexical, syntactic and semantic ambiguities remain.
Names of |
functions
The ambiguity in the style of writing a function should not be confused with a multivalued function, which can and should be defined in a deterministic and unambiguous way. Several special functions still do not have established notations. Usually, the conversion to another notation requires to scale the argument or the resulting value; sometimes, the same name of the function is used, causing confusions. Examples of such underestablished functions
Sinc function
Elliptic integral of the third kind; translating elliptic integral form MAPLE to Mathematica, one should replace the second argument to its square, see TalkElliptic integralList of notations; dealing with complex values, this may cause problems.
Exponential integral
Hermite polynomial
Expressions
Ambiguous expressions often appear in physical and mathematical texts.
It is common practice to omit multiplication signs in mathematical expressions. Also, it is common to give the same name to a variable and a function, for example, . Then, |
if one sees , there is no way to distinguish whether it means multiplied by , or function evaluated at argument equal to . In each case of use of such notations, the reader is supposed to be able to perform the deduction and reveal the true meaning.
Creators of algorithmic languages try to avoid ambiguities. Many algorithmic languages C and Fortran require the character as symbol of multiplication. The Wolfram Language used in Mathematica allows the user to omit the multiplication symbol, but requires square brackets to indicate the argument of a function; square brackets are not allowed for grouping of expressions. Fortran, in addition, does not allow use of the same name identifier for different objects, for example, function and variable; in particular, the expression ffx is qualified as an error.
The order of operations may depend on the context. In most programming languages, the operations of division and multiplication have equal priority and are executed from left to right. Until the last centur |
y, many editorials assumed that multiplication is performed first, for example, is interpreted as ; in this case, the insertion of parentheses is required when translating the formulas to an algorithmic language. In addition, it is common to write an argument of a function without parenthesis, which also may lead to ambiguity.
In the scientific journal style, one uses roman letters to denote elementary functions, whereas variables are written using italics.
For example, in mathematical journals the expression
does not denote the sine function, but the
product of the three variables
,
,
, although in the informal notation of a slide presentation it may stand for .
Commas in multicomponent subscripts and superscripts are sometimes omitted; this is also potentially ambiguous notation.
For example, in the notation , the reader can only infer from the context whether it means a singleindex object, taken with the subscript equal to product of variables , and , or it is an indication to a trivalent tensor.
Exam |
ples of potentially confusing ambiguous mathematical expressions
An expression such as can be understood to mean either or . Often the author's intention can be understood from the context, in cases where only one of the two makes sense, but an ambiguity like this should be avoided, for example by writing or .
The expression means in several texts, though it might be thought to mean , since commonly means . Conversely, might seem to mean , as this exponentiation notation usually denotes function iteration in general, means . However, for trigonometric and hyperbolic functions, this notation conventionally means exponentiation of the result of function application.
The expression can be interpreted as meaning ; however, it is more commonly understood to mean .
Notations in quantum optics and quantum mechanics
It is common to define the coherent states in quantum optics with and states with fixed number of photons with . Then, there is an "unwritten rule" the state is coherent if there are more G |
reek characters than Latin characters in the argument, and photon state if the Latin characters dominate. The ambiguity becomes even worse, if is used for the states with certain value of the coordinate, and means the state with certain value of the momentum, which may be used in books on quantum mechanics. Such ambiguities easily lead to confusions, especially if some normalized adimensional, dimensionless variables are used. Expression may mean a state with single photon, or the coherent state with mean amplitude equal to 1, or state with momentum equal to unity, and so on. The reader is supposed to guess from the context.
Ambiguous terms in physics and mathematics
Some physical quantities do not yet have established notations; their value and sometimes even dimension, as in the case of the Einstein coefficients, depends on the system of notations. Many terms are ambiguous. Each use of an ambiguous term should be preceded by the definition, suitable for a specific case. Just like Ludwig Wittgenstein st |
ates in Tractatus LogicoPhilosophicus "...Only in the context of a proposition has a name meaning."
A highly confusing term is gain. For example, the sentence "the gain of a system should be doubled", without context, means close to nothing.
It may mean that the ratio of the output voltage of an electric circuit to the input voltage should be doubled.
It may mean that the ratio of the output power of an electric or optical circuit to the input power should be doubled.
It may mean that the gain of the laser medium should be doubled, for example, doubling the population of the upper laser level in a quasitwo level system assuming negligible absorption of the groundstate.
The term intensity is ambiguous when applied to light. The term can refer to any of irradiance, luminous intensity, radiant intensity, or radiance, depending on the background of the person using the term.
Also, confusions may be related with the use of atomic percent as measure of concentration of a dopant, or resolution of an imaging s |
ystem, as measure of the size of the smallest detail which still can be resolved at the background of statistical noise. See also Accuracy and precision and its talk.
The Berry paradox arises as a result of systematic ambiguity in the meaning of terms such as "definable" or "nameable". Terms of this kind give rise to vicious circle fallacies. Other terms with this type of ambiguity are satisfiable, true, false, function, property, class, relation, cardinal, and ordinal.
Mathematical interpretation of ambiguity
In mathematics and logic, ambiguity can be considered to be an instance of the logical concept of underdeterminationfor example, leaves open what the value of X iswhile its opposite is a selfcontradiction, also called inconsistency, paradoxicalness, or oxymoron, or in mathematics an inconsistent systemsuch as , which has no solution.
Logical ambiguity and selfcontradiction is analogous to visual ambiguity and impossible objects, such as the Necker cube and impossible cube, or many of the drawings |
of M. C. Escher.
Constructed language
Some languages have been created with the intention of avoiding ambiguity, especially lexical ambiguity. Lojban and Loglan are two related languages which have been created for this, focusing chiefly on syntactic ambiguity as well. The languages can be both spoken and written. These languages are intended to provide a greater technical precision over big natural languages, although historically, such attempts at language improvement have been criticized. Languages composed from many diverse sources contain much ambiguity and inconsistency. The many exceptions to syntax and semantic rules are timeconsuming and difficult to learn.
Biology
In structural biology, ambiguity has been recognized as a problem for studying protein conformations. The analysis of a protein threedimensional structure consists in dividing the macromolecule into subunits called domains. The difficulty of this task arises from the fact that different definitions of what a domain is can be used e.g. |
folding autonomy, function, thermodynamic stability, or domain motions, which sometimes results in a single protein having differentyet equally validdomain assignments.
Christianity and Judaism
Christianity and Judaism employ the concept of paradox synonymously with "ambiguity". Many Christians and Jews endorse Rudolf Otto's description of the sacred as 'mysterium tremendum et fascinans', the aweinspiring mystery which fascinates humans. The orthodox Catholic writer G. K. Chesterton regularly employed paradox to tease out the meanings in common concepts which he found ambiguous or to reveal meaning often overlooked or forgotten in common phrases. The title of one of his most famous books, Orthodoxy, itself employing such a paradox.
Music
In music, pieces or sections which confound expectations and may be or are interpreted simultaneously in different ways are ambiguous, such as some polytonality, polymeter, other ambiguous meters or rhythms, and ambiguous phrasing, or Stein 2005, p.79 any aspect of music |
. The music of Africa is often purposely ambiguous. To quote Sir Donald Francis Tovey 1935, p.195, "Theorists are apt to vex themselves with vain efforts to remove uncertainty just where it has a high aesthetic value."
Visual art
In visual art, certain images are visually ambiguous, such as the Necker cube, which can be interpreted in two ways. Perceptions of such objects remain stable for a time, then may flip, a phenomenon called multistable perception.
The opposite of such ambiguous images are impossible objects.
Pictures or photographs may also be ambiguous at the semantic level the visual image is unambiguous, but the meaning and narrative may be ambiguous is a certain facial expression one of excitement or fear, for instance?
Social psychology and the bystander effect
In social psychology, ambiguity is a factor used in determining peoples' responses to various situations. High levels of ambiguity in an emergency e.g. an unconscious man lying on a park bench make witnesses less likely to offer any |
sort of assistance, due to the fear that they may have misinterpreted the situation and acted unnecessarily. Alternately, nonambiguous emergencies e.g. an injured person verbally asking for help illicit more consistent intervention and assistance. With regard to the bystander effect, studies have shown that emergencies deemed ambiguous trigger the appearance of the classic bystander effect wherein more witnesses decrease the likelihood of any of them helping far more than nonambiguous emergencies.
Computer science
In computer science, the SI prefixes kilo, mega and giga were historically used in certain contexts to mean either the first three powers of 1024 1024, 10242 and 10243 contrary to the metric system in which these units unambiguously mean one thousand, one million, and one billion. This usage is particularly prevalent with electronic memory devices e.g. DRAM addressed directly by a binary machine register where a decimal interpretation makes no practical sense.
Subsequently, the Ki, Mi, and Gi pre |
fixes were introduced so that binary prefixes could be written explicitly, also rendering k, M, and G unambiguous in texts conforming to the new standardthis led to a new ambiguity in engineering documents lacking outward trace of the binary prefixes necessarily indicating the new style as to whether the usage of k, M, and G remains ambiguous old style or not new style. 1 M where M is ambiguously 1,000,000 or 1,048,576 is less uncertain than the engineering value 1.0e6 defined to designate the interval 950,000 to 1,050,000. As nonvolatile storage devices begin to exceed 1 GB in capacity where the ambiguity begins to routinely impact the second significant digit, GB and TB almost always mean 109 and 1012 bytes.
See also
References
External links
Collection of Ambiguous or InconsistentIncomplete Statements
Leaving out ambiguities when writing
Semantics
Mathematical notation
Concepts in epistemology
Barriers to critical thinking
Formal semantics natural language |
Abel is a Biblical figure in the Book of Genesis within Abrahamic religions. He was the younger brother of Cain, and the younger son of Adam and Eve, the first couple in Biblical history. He was a shepherd who offered his firstborn flock up to God as an offering. God accepted his offering but not his brother's. Cain then killed Abel out of jealousy.
According to Genesis, this was the first murder in the history of mankind.
Genesis narrative
Interpretations
Jewish and Christian interpretations
According to the narrative in Genesis, Abel Hbel, in pausa Hel; Hbel; , Hbl is Eve's second son. His name in Hebrew is composed of the same three consonants as a root meaning "breath". Julius Wellhausen has proposed that the name is independent of the root. Eberhard Schrader had previously put forward the Akkadian Old Assyrian dialect ablu "son" as a more likely etymology.
In Christianity, comparisons are sometimes made between the death of Abel and that of Jesus, the former thus seen as being the first martyr. I |
n Jesus speaks of Abel as "righteous", and the Epistle to the Hebrews states that "The blood of sprinkling ... speaks better things than that of Abel" . The blood of Jesus is interpreted as bringing mercy; but that of Abel as demanding vengeance hence the curse and mark.
Abel is invoked in the litany for the dying in the Roman Catholic Church, and his sacrifice is mentioned in the Canon of the Mass along with those of Abraham and Melchizedek. The Alexandrian Rite commemorates him with a feast day on December 28.
According to the Coptic Book of Adam and Eve at 2115, and the Syriac Cave of Treasures, Abel's body, after many days of mourning, was placed in the Cave of Treasures, before which Adam and Eve, and descendants, offered their prayers. In addition, the Sethite line of the Generations of Adam swear by Abel's blood to segregate themselves from the unrighteous.
In the Book of Enoch 227, regarded by most Christian and Jewish traditions as extrabiblical, the soul of Abel is described as having been appoi |
nted as the chief of martyrs, crying for vengeance, for the destruction of the seed of Cain. This view is later repeated in the Testament of Abraham A13 B11, where Abel has been raised to the position as the judge of the souls.
Sethian Gnostic interpretation
In the Apocryphon of John, a work belonging to Sethian Gnosticism, Abel is the offspring of Yaldaboath and Eve, who is placed over the elements of water and earth as Elohim, but was only given his name as a form of deception.
Mandaean interpretation
According to Mandaean beliefs and scriptures including the Qolast, the Book of John and Genz Rabb, Abel is cognate with the angelic soteriological figure Hibil Ziwa, , sometimes translated "Splendid Hibel", who is spoken of as a son of Hayyi or of Manda dHayyi, and as a brother to Anush Enosh and to Sheetil Seth, who is the son of Adam. Elsewhere, Anush is spoken of as the son of Sheetil, and Sheetil as the son of Hibil, where Hibil came to Adam and Eve as a young boy when they were still virgins, but was |
called their son. Hibil is an important lightworld being uthra who conquered the World of Darkness. As Yawar Hibil, he is one of multiple figures known as Yawar , being so named by and after his father.
Islamic interpretation
According to Shi'a Muslim belief, Abel "Habeel" is buried in the Nabi Habeel Mosque, located on the west mountains of Damascus, near the Zabadani Valley, overlooking the villages of the Barada river Wadi Barada, in Syria. Shi'a are frequent visitors of this mosque for ziyarat. The mosque was built by Ottoman Wali Ahmad Pasha in 1599.
Notes
References
Bereshit parashah
Biblical murder victims
Book of Genesis people
Children of Adam and Eve
Male murder victims
Shepherds
Uthras
Hebrew Bible people in Mandaeism |
An animal is a multicellular, eukaryotic organism of the kingdom Animalia or Metazoa.
Animal, Animals, or The Animal may also refer to
People
The Animal nickname, a set index of people nicknamed "The Animal" or "Animal"
Professional wrestlers
Road Warrior Animal, commonly shortened to "Animal", the bestknown ring persona of Joe Laurinaitis 19602020
Animal Hamaguchi, ring name of Japanese retired wrestler Heigo Hamaguchi born 1947
George Steele 19372017, American professional wrestler, author and actor known as "The Animal"
Dave Bautista born 1969, American retired professional wrestler whose nickname is "The Animal"
Books and publications
Animal book, full title Animal The Definitive Visual Guide to The World's WildLife, a 2003 nonfiction book by David Burnie and several coauthors
Animal, 2012 novel by K'wan Foye
Animal journal, full title Animal An International Journal of Animal Bioscience, British academic journal
Animals novel, a 2014 novel by Emma Jane Unsworth
Film and television
Film
Ani |
mal 1977 film, a French film L'Animal starring JeanPaul Belmondo and Raquel Welch
Animal 2001 film, an Argentine comedy film by Sergio Bizzio with Carlos Roff
Animal 2005 film, an American directtovideo action drama film starring Ving Rhames and Terrance Howard
Animal 2014 film, an American horror film starring Keke Palmer
Animals 2003 film, a standup show written and performed by Ricky Gervais
Animals 2012 film, a Spanish film
Animals 2014 film, a British drama film written by and starring David Dastmalchian
Animals 2017 film, a German film
Animals 2019 film, an Australian film
The Animal, a 2001 American comedy film featuring Rob Schneider
The Animals film, a 2012 Filipino comingofage film by Gino M. Santos
Television
Animals American TV series, a 20162018 animated series
Animals South Korean TV series, a 2015 realityvariety show
"Animals" The Goodies, a 1980 episode
"Animals" Men Behaving Badly, a 1992 episode
"Animals" Off the Air, a 2011 episode
"Animals" The Vicar of Dibley, a 1994 epis |
ode
"The Animals" Orange Is the New Black, a 2016 episode
Animal audio drama, a 2011 audio drama based on Doctor Who
Characters
Animal Muppet, a character from the television series The Muppet Show
Animal, a character in the television series Takeshi's Castle
Animal, played by Ken Hudson Campbell, a character on the TV sitcom Herman's Head
Dennis "Animal" Price, a character on the TV series Lou Grant
Music
The Animals, a British rock band
A.N.I.M.A.L., an Argentinian heavy metal band
Animal Nick Culmer lead singer of the AntiNowhere League
Albums
Animal Animosity album, 2007
Animal BarKays album, 1989
Animal Big Scary album, 2016
Animal Kesha album, 2010
Animal Lump album, 2021
Animal Motor Ace album, 2005
Animal Maria Becerra album, 2021
Animals Pink Floyd album, 1977
Animals This Town Needs Guns album, 2008
Animals EP by Ryan Starx, 2013
The Animals American album, by The Animals, 1964
The Animals British album, by The Animals, 1964
Animal, a 2009 album by AutoKratz
Animal, a 2013 |
album by Berlin
Animal, a 2008 album by Far East Movement
Animal!, a 2008 album by Margot the Nuclear So and So's
Songs
"Animal"
"Animal", by Against Me! from New Wave
"Animal" lvaro Soler song, 2017
"Animal", by Ani DiFranco from Educated Guess
"Animal", by Aurora from A Different Kind of Human Step 2
"Animal", by Black Light Burns from Cruel Melody
"Animal" Conor Maynard song, 2013
"Animal" Def Leppard song, 1987
"Animal", by Ellie Goulding from Lights
"Animal" Jebediah song, 1999
"Animal" Juvenile song, 2006
"Animal", by Karen O and the Kids from Where the Wild Things Are
"Animal", by Kat DeLuna from 9 Lives
"Animal", by Kesha from Animal
"Animal", by the Men from Open Your Heart, 2012
"Animal" Miike Snow song, 2009
"Animal", by Mindless Self Indulgence from If
"Animal", by Mudmen from Overrated
"Animal", by Nada Surf from You Know Who You Are, 2016
"Animal" Neon Trees song, 2010
"Animal" Pearl Jam song, 1994
"Animal" R.E.M. song, 2004
"Animal" R.I.O. song, 2011
"Animal", by Sub |
humans from Demolition War
"Animal", by Sunhouse from Crazy On The Weekend
"Animal", by The Kinks from To the Bone
"Animal", by Toto from Past to Present 19771990
"Animal" Troye Sivan song, 2018
"Animals"
"Animals" Architects song, 2020
"Animals", by CocoRosie from The Adventures of Ghosthorse and Stillborn
"Animals", by Coldplay as one of the Bsides for "Clocks"
"Animals", by Dead Poetic from Vices
"Animals" Kevin Ayers song, 1980
"Animals" Maroon 5 song, 2014
"Animals" Martin Garrix song, 2013
"Animals" Muse song, 2012
"Animals" Nickelback song, 2005
"Animals", by Talking Heads from Fear of Music
"Animals", by The End from Elementary
"Animals", by Todrick Hall featuring Matt Bloyd from Forbidden
"Animal Fk Like a Beast", by W.A.S.P., 1984
"The Animal"
"The Animal" Disturbed song, 2010
"The Animal", by Steve Vai from Passion and Warfare
Other
ANIMAL computer worm, an early selfreplicating computer program
ANIMAL image processing, an interactive software environment for image processin |
g
Animals Israeli organization, an animal rights group based in Israel
See also
Animals, Animals, Animals, an American educational television series 19761981
Animalia disambiguation
Animalism disambiguation
Operation Animals, a World War II Allied deception operation in Greece |
The aardvark ; Orycteropus afer is a mediumsized, burrowing, nocturnal mammal native to Africa. It is the only living species of the order Tubulidentata, although other prehistoric species and genera of Tubulidentata are known. Unlike most other insectivores, it has a long piglike snout, which is used to sniff out food. It roams over most of the southern twothirds of the African continent, avoiding areas that are mainly rocky. A nocturnal feeder, it subsists on ants and termites, which it will dig out of their hills using its sharp claws and powerful legs. It also digs to create burrows in which to live and rear its young. The animal is listed as "least concern" by the IUCN, although its numbers are decreasing. Aardvarks are afrotheres, a clade which also includes elephants, manatees, and hyraxes.
Name and taxonomy
Name
The aardvark is sometimes colloquially called the "African ant bear", "anteater" not to be confused with the South American anteater, or the "Cape anteater" after the Cape of Good Hope. Th |
e name "aardvark" is Afrikaans , comes from earlier Afrikaans erdvark and means "earth pig" or "ground pig" aarde "earthground", vark "pig", because of its burrowing habits. The name Orycteropus means "burrowing foot", and the name afer refers to Africa. The name of the aardvark's order, Tubulidentata, comes from the tubulestyle teeth.
Taxonomy
The aardvark is not closely related to the pig; rather, it is the sole extant representative of the obscure mammalian order Tubulidentata, in which it is usually considered to form one variable species of the genus Orycteropus, the sole surviving genus in the family Orycteropodidae. The aardvark is not closely related to the South American anteater, despite sharing some characteristics and a superficial resemblance. The similarities are based on convergent evolution. The closest living relatives of the aardvark are the elephant shrews, tenrecs and golden moles. Along with the sirenians, hyraxes, elephants, and their extinct relatives, these animals form the superord |
er Afrotheria. Studies of the brain have shown the similarities with Condylarthra, and given the clade's status as a wastebasket taxon it may mean some species traditionally classified as "condylarths" are actually stemaardvarks.
Evolutionary history
Based on fossils, Bryan Patterson has concluded that early relatives of the aardvark appeared in Africa around the end of the Paleocene. The ptolemaiidans, a mysterious clade of mammals with uncertain affinities, may actually be stemaardvarks, either as a sister clade to Tubulidentata or as a grade leading to true tubulidentates.
The first unambiguous tubulidentate was probably Myorycteropus africanus from Kenyan Miocene deposits. The earliest example from the genus Orycteropus was Orycteropus mauritanicus, found in Algeria in deposits from the middle Miocene, with an equally old version found in Kenya. Fossils from the aardvark have been dated to 5 million years, and have been located throughout Europe and the Near East.
The mysterious Pleistocene Plesioryct |
eropus from Madagascar was originally thought to be a tubulidentate that was descended from ancestors that entered the island during the Eocene. However, a number of subtle anatomical differences coupled with recent molecular evidence now lead researchers to believe that Plesiorycteropus is a relative of golden moles and tenrecs that achieved an aardvarklike appearance and ecological niche through convergent evolution.
Subspecies
The aardvark has seventeen poorly defined subspecies listed
Orycteropus afer afer
O. a. adametzi Grote, 1921
O. a. aethiopicus Sundevall, 1843
O. a. angolensis Zukowsky Haltenorth, 1957
O. a. erikssoni Lnnberg, 1906
O. a. faradjius Hatt, 1932
O. a. haussanus Matschie, 1900
O. a. kordofanicus Rothschild, 1927
O. a. lademanni Grote, 1911
O. a. leptodon Hirst, 1906
O. a. matschiei Grote, 1921
O. a. observandus Grote, 1921
O. a. ruvanensis Grote, 1921
O. a. senegalensis Lesson, 1840
O. a. somalicus Lydekker, 1908
O. a. wardi Lydekker, 1908
O. a. wertheri Ma |
tschie, 1898
The 1911 Encyclopdia Britannica also mentions O. a. capensis or Cape antbear from South Africa.
Description
The aardvark is vaguely piglike in appearance. Its body is stout with a prominently arched back and is sparsely covered with coarse hairs. The limbs are of moderate length, with the rear legs being longer than the forelegs. The front feet have lost the pollex or 'thumb', resulting in four toes, while the rear feet have all five toes. Each toe bears a large, robust nail which is somewhat flattened and shovellike, and appears to be intermediate between a claw and a hoof. Whereas the aardvark is considered digitigrade, it appears at times to be plantigrade. This confusion happens because when it squats it stands on its soles. A contributing characteristic to the burrow digging capabilities of aardvarks is an endosteal tissue called compacted coarse cancellous bone CCCB. The stress and strain resistance provided by CCCB allows aardvarks to create their burrows, ultimately leading to a favora |
ble environment for plants and a variety of animals.
An aardvark's weight is typically between . An aardvark's length is usually between , and can reach lengths of when its tail which can be up to is taken into account. It is tall at the shoulder, and has a girth of about . It is the largest member of the proposed clade Afroinsectiphilia. The aardvark is pale yellowishgray in color and often stained reddishbrown by soil. The aardvark's coat is thin, and the animal's primary protection is its tough skin. Its hair is short on its head and tail; however its legs tend to have longer hair. The hair on the majority of its body is grouped in clusters of 34 hairs. The hair surrounding its nostrils is dense to help filter particulate matter out as it digs. Its tail is very thick at the base and gradually tapers.
Head
The greatly elongated head is set on a short, thick neck, and the end of the snout bears a disc, which houses the nostrils. It contains a thin but complete zygomatic arch. The head of the aardvark co |
ntains many unique and different features. One of the most distinctive characteristics of the Tubulidentata is their teeth, Instead of having a pulp cavity, each tooth has a cluster of thin, hexagonal, upright, parallel tubes of vasodentin a modified form of dentine, with individual pulp canals, held together by cementum. The number of columns is dependent on the size of the tooth, with the largest having about 1,500. The teeth have no enamel coating and are worn away and regrow continuously. The aardvark is born with conventional incisors and canines at the front of the jaw, which fall out and are not replaced. Adult aardvarks have only cheek teeth at the back of the jaw, and have a dental formula of These remaining teeth are peglike and rootless and are of unique composition. The teeth consist of 14 upper and 12 lower jaw molars. The nasal area of the aardvark is another unique area, as it contains ten nasal conchae, more than any other placental mammal.
The sides of the nostrils are thick with hair. The |
tip of the snout is highly mobile and is moved by modified mimetic muscles. The fleshy dividing tissue between its nostrils probably has sensory functions, but it is uncertain whether they are olfactory or vibratory in nature. Its nose is made up of more turbinate bones than any other mammal, with between 9 and 11, compared to dogs with 4 to 5. With a large quantity of turbinate bones, the aardvark has more space for the moist epithelium, which is the location of the olfactory bulb. The nose contains nine olfactory bulbs, more than any other mammal. Its keen sense of smell is not just from the quantity of bulbs in the nose but also in the development of the brain, as its olfactory lobe is very developed. The snout resembles an elongated pig snout. The mouth is small and tubular, typical of species that feed on ants and termites. The aardvark has a long, thin, snakelike, protruding tongue as much as long and elaborate structures supporting a keen sense of smell. The ears, which are very effective, are disprop |
ortionately long, about long. The eyes are small for its head, and consist only of rods.
Digestive system
The aardvark's stomach has a muscular pyloric area that acts as a gizzard to grind swallowed food up, thereby rendering chewing unnecessary. Its cecum is large. Both sexes emit a strong smelling secretion from an anal gland. Its salivary glands are highly developed and almost completely ring the neck; their output is what causes the tongue to maintain its tackiness. The female has two pairs of teats in the inguinal region.
Genetically speaking, the aardvark is a living fossil, as its chromosomes are highly conserved, reflecting much of the early eutherian arrangement before the divergence of the major modern taxa.
Habitat and range
Aardvarks are found in subSaharan Africa, where suitable habitat savannas, grasslands, woodlands and bushland and food i.e., ants and termites is available. They spend the daylight hours in dark burrows to avoid the heat of the day. The only major habitat that they are not |
present in is swamp forest, as the high water table precludes digging to a sufficient depth. They also avoid terrain rocky enough to cause problems with digging. They have been documented as high as in Ethiopia. They are present throughout subSaharan Africa all the way to South Africa with few exceptions including the coastal areas of Namibia, Ivory Coast, and Ghana. They are not found in Madagascar.
Ecology and behaviour
Aardvarks live for up to 23 years in captivity. Its keen hearing warns it of predators lions, leopards, cheetahs, African wild dogs, hyenas, and pythons. Some humans also hunt aardvarks for meat. Aardvarks can dig fast or run in zigzag fashion to elude enemies, but if all else fails, they will strike with their claws, tail and shoulders, sometimes flipping onto their backs lying motionless except to lash out with all four feet. They are capable of causing substantial damage to unprotected areas of an attacker. They will also dig to escape as they can. Sometimes, when pressed, aardvarks ca |
n dig extremely quickly
.
Feeding
The aardvark is nocturnal and is a solitary creature that feeds almost exclusively on ants and termites myrmecophagy; the only fruit eaten by aardvarks is the aardvark cucumber. In fact, the cucumber and the aardvark have a symbiotic relationship as they eat the subterranean fruit, then defecate the seeds near their burrows, which then grow rapidly due to the loose soil and fertile nature of the area. The time spent in the intestine of the aardvark helps the fertility of the seed, and the fruit provides needed moisture for the aardvark. They avoid eating the African driver ant and red ants. Due to their stringent diet requirements, they require a large range to survive. An aardvark emerges from its burrow in the late afternoon or shortly after sunset, and forages over a considerable home range encompassing . While foraging for food, the aardvark will keep its nose to the ground and its ears pointed forward, which indicates that both smell and hearing are involved in the sear |
ch for food. They zigzag as they forage and will usually not repeat a route for 58 days as they appear to allow time for the termite nests to recover before feeding on it again.
During a foraging period, they will stop to dig a "V" shaped trench with their forefeet and then sniff it profusely as a means to explore their location. When a concentration of ants or termites is detected, the aardvark digs into it with its powerful front legs, keeping its long ears upright to listen for predators, and takes up an astonishing number of insects with its long, sticky tongueas many as 50,000 in one night have been recorded. Its claws enable it to dig through the extremely hard crust of a termite or ant mound quickly. It avoids inhaling the dust by sealing the nostrils. When successful, the aardvark's long up to tongue licks up the insects; the termites' biting, or the ants' stinging attacks are rendered futile by the tough skin. After an aardvark visit at a termite mound, other animals will visit to pick up all the l |
eftovers. Termite mounds alone don't provide enough food for the aardvark, so they look for termites that are on the move. When these insects move, they can form columns long and these tend to provide easy pickings with little effort exerted by the aardvark. These columns are more common in areas of livestock or other hoofed animals. The trampled grass and dung attract termites from the Odontotermes, Microtermes, and Pseudacanthotermes genera.
On a nightly basis they tend to be more active during the first portion of night roughly the four hours between 800p.m. and 1200a.m.; however, they don't seem to prefer bright or dark nights over the other. During adverse weather or if disturbed they will retreat to their burrow systems. They cover between per night; however, some studies have shown that they may traverse as far as in a night.
Vocalization
The aardvark is a rather quiet animal. However, it does make soft grunting sounds as it forages and loud grunts as it makes for its tunnel entrance. It makes a b |
leating sound if frightened. When it is threatened it will make for one of its burrows. If one is not close it will dig a new one rapidly. This new one will be short and require the aardvark to back out when the coast is clear.
Movement
The aardvark is known to be a good swimmer and has been witnessed successfully swimming in strong currents. It can dig a yard of tunnel in about five minutes, but otherwise moves fairly slowly.
When leaving the burrow at night, they pause at the entrance for about ten minutes, sniffing and listening. After this period of watchfulness, it will bound out and within seconds it will be away. It will then pause, prick its ears, twisting its head to listen, then jump and move off to start foraging.
Aside from digging out ants and termites, the aardvark also excavates burrows in which to live, which generally fall into one of three categories burrows made while foraging, refuge and resting location, and permanent homes. Temporary sites are scattered around the home range and are |
used as refuges, while the main burrow is also used for breeding. Main burrows can be deep and extensive, have several entrances and can be as long as . These burrows can be large enough for a person to enter. The aardvark changes the layout of its home burrow regularly, and periodically moves on and makes a new one. The old burrows are an important part of the African wildlife scene. As they are vacated, then they are inhabited by smaller animals like the African wild dog, anteating chat, Nycteris thebaica and warthogs. Other animals that use them are hares, mongooses, hyenas, owls, pythons, and lizards. Without these refuges many animals would die during wildfire season. Only mothers and young share burrows; however, the aardvark is known to live in small family groups or as a solitary creature. If attacked in the tunnel, it will escape by digging out of the tunnel thereby placing the fresh fill between it and its predator, or if it decides to fight it will roll onto its back, and attack with its claws. The |
aardvark has been known to sleep in a recently excavated ant nest, which also serves as protection from its predators.
Reproduction
Aardvarks pair only during the breeding season; after a gestation period of seven months, one cub weighing around is born during MayJuly. When born, the young has flaccid ears and many wrinkles. When nursing, it will nurse off each teat in succession. After two weeks, the folds of skin disappear and after three, the ears can be held upright. After 56 weeks, body hair starts growing. It is able to leave the burrow to accompany its mother after only two weeks and eats termites at 9 weeks, and is weaned between three months and 16 weeks. At six months of age, it is able to dig its own burrows, but it will often remain with the mother until the next mating season, and is sexually mature from approximately two years of age.
Conservation
Aardvarks were thought to have declining numbers, however, this is possibly because they are not readily seen. There are no definitive counts bec |
ause of their nocturnal and secretive habits; however, their numbers seem to be stable overall. They are not considered common anywhere in Africa, but due to their large range, they maintain sufficient numbers. There may be a slight decrease in numbers in eastern, northern, and western Africa. Southern African numbers are not decreasing. It receives an official designation from the IUCN as least concern. However, they are a species in a precarious situation, as they are so dependent on such specific food; therefore if a problem arises with the abundance of termites, the species as a whole would be affected drastically.
Aardvarks handle captivity well. The first zoo to have one was London Zoo in 1869, which had an animal from South Africa.
Mythology and popular culture
In African folklore, the aardvark is much admired because of its diligent quest for food and its fearless response to soldier ants. Hausa magicians make a charm from the heart, skin, forehead, and nails of the aardvark, which they then procee |
d to pound together with the root of a certain tree. Wrapped in a piece of skin and worn on the chest, the charm is said to give the owner the ability to pass through walls or roofs at night. The charm is said to be used by burglars and those seeking to visit young girls without their parents' permission. Also, some tribes, such as the Margbetu, Ayanda, and Logo, will use aardvark teeth to make bracelets, which are regarded as good luck charms. The meat, which has a resemblance to pork, is eaten in certain cultures.
The ancient Egyptian god Set is usually depicted with the head of an unidentified animal, whose similarity to an aardvark has been noted in scholarship.
The titular character of Arthur, an animated television series for children based on a book series and produced by WGBH, shown in more than 180 countries, is an aardvark. In the first book of the series, Arthur's Nose 1976, he has a long, aardvarklike nose, but in later books, his face becomes more rounded.
Otis the Aardvark was a puppet charac |
ter used on Children's BBC programming.
An aardvark features as the antagonist in the cartoon The Ant and the Aardvark as well as in the Canadian animated series The Raccoons.
The supersonic fighterbomber F111FB111 was nicknamed the Aardvark because of its long nose resembling the animal. It also had similarities with its nocturnal missions flown at a very low level employing ordnance that could penetrate deep into the ground. In the US Navy, the squadron VF114 was nicknamed the Aardvarks, flying F4s and then F14s. The squadron mascot was adapted from the animal in the comic strip B.C., which the F4 was said to resemble.
Cerebus the Aardvark is a 300issue comic book series by Dave Sim.
Footnotes
References
External links
IUCNSSC Afrotheria Specialist Group
A YouTube video introducing the Bronx Zoo's aardvarks
"The Biology of the Aardvark Orycteropus afer" a diploma thesis without images
"The Biology of the Aardvark" Orycteropus afer" the thesis with images
Orycteropus
Mammals of Africa
Myrmecoph |
agous mammals
Mammals described in 1766
Extant Zanclean first appearances
Taxa named by Peter Simon Pallas |
The aardwolf Proteles cristata is an insectivorous mammal in the family Hyaenidae, native to East and Southern Africa. Its name means "earthwolf" in Afrikaans and Dutch. It is also called "maanhaarjackal" Afrikaans for "manejackal", "termiteeating hyena" and "civet hyena", based on its habit of secreting substances from its anal gland, a characteristic shared with the African civet. Unlike many of its relatives in the order Carnivora, the aardwolf does not hunt large animals. It eats insects and their larvae, mainly termites; one aardwolf can lap up as many as 250,000 termites during a single night using its long, sticky tongue. The aardwolf's tongue has adapted to be tough enough to withstand the strong bite of termites.
The aardwolf lives in the shrublands of eastern and southern Africa open lands covered with stunted trees and shrubs. It is nocturnal, resting in burrows during the day and emerging at night to seek food.
Taxonomy
The aardwolf is generally classified with the hyena family Hyaenidae, thoug |
h it was formerly placed in its own family Protelidae. Early on, scientists felt that it was merely mimicking the striped hyena, which subsequently led to the creation of Protelidae. Recent studies have suggested that the aardwolf probably diverged from other hyaenids early on; how early is still unclear, as the fossil record and genetic studies disagree by 10 million years.
The aardwolf is the only surviving species in the subfamily Protelinae. There is disagreement as to whether the species is monotypic, or can be divided into subspecies P. c. cristatus of Southern Africa and P. c. septentrionalis of East Africa.
Etymology
The generic name proteles comes from two words both of Greek origin, protos and teleos which combined means "complete in front" based on the fact that they have five toes on their front feet and four on the rear. The specific name, cristatus, comes from Latin and means "provided with a comb", relating to their mane.
Description
The aardwolf resembles a very thin striped hyena, but wit |
h a more slender muzzle, black vertical stripes on a coat of yellowish fur, and a long, distinct mane down the midline of the neck and back. It also has one or two diagonal stripes down the fore and hindquarters, along with several stripes on its legs. The mane is raised during confrontations to make the aardwolf appear larger. It is missing the throat spot that others in the family have. Its lower leg from the knee down is all black, and its tail is bushy with a black tip.
The aardwolf is about long, excluding its bushy tail, which is about long, and stands about tall at the shoulders. An adult aardwolf weighs approximately , sometimes reaching . The aardwolves in the south of the continent tend to be smaller about than the eastern version around . This makes the aardwolf, the smallest extant member of the Hyaenidae family. The front feet have five toes each, unlike the fourtoed hyena. The teeth and skull are similar to those of other hyenas, though smaller, and its cheek teeth are specialised for eating |
insects. It does still have canines, but, unlike other hyenas, these teeth are used primarily for fighting and defense. Its ears, which are large, are very similar to those of the striped hyena.
As an aardwolf ages, it will normally lose some of its teeth, though this has little impact on its feeding habits due to the softness of the insects that it eats.
Distribution and habitat
Aardwolves live in open, dry plains and bushland, avoiding mountainous areas. Due to their specific food requirements, they are only found in regions where termites of the family Hodotermitidae occur. Termites of this family depend on dead and withered grass and are most populous in heavily grazed grasslands and savannahs, including farmland. For most of the year, aardwolves spend time in shared territories consisting of up to a dozen dens, which are occupied for six weeks at a time.
There are two distinct populations one in Southern Africa, and another in East and Northeast Africa. The species does not occur in the intermediary |
miombo forests.
An adult pair, along with their mostrecent offspring, occupies a territory of .
Behavior
Aardwolves are shy and nocturnal, sleeping in burrows by day. They will, on occasion during the winter, become diurnal feeders. This happens during the coldest periods as they then stay in at night to conserve heat.
They have often been mistaken for solitary animals. In fact, they live as monogamous pairs with their young. If their territory is infringed upon, they will chase the intruder up to or to the border. If the intruder is caught, which rarely happens, a fight will occur, which is accompanied by soft clucking, hoarse barking, and a type of roar. The majority of incursions occur during mating season, when they can occur once or twice per week. When food is scarce, the stringent territorial system may be abandoned and as many as three pairs may occupy a single territory.
The territory is marked by both sexes, as they both have developed anal glands from which they extrude a black substance that |
is smeared on rocks or grass stalks in long streaks. Aardwolves also have scent glands on the forefoot and penile pad. They often mark near termite mounds within their territory every 20 minutes or so. If they are patrolling their territorial boundaries, the marking frequency increases drastically, to once every . At this rate, an individual may mark 60 marks per hour, and upwards of 200 per night.
An aardwolf pair may have up to 10 dens, and numerous feces middens, within their territory. When they deposit excreta at their middens, they dig a small hole and cover it with sand. Their dens are usually abandoned aardvark, springhare, or porcupine dens, or on occasion they are crevices in rocks. They will also dig their own dens, or enlarge dens started by springhares. They typically will only use one or two dens at a time, rotating through all of their dens every six months. During the summer, they may rest outside their den during the night, and sleep underground during the heat of the day.
Aardwolves are n |
ot fast runners nor are they particularly adept at fighting off predators. Therefore, when threatened, the aardwolf may attempt to mislead its foe by doubling back on its tracks. If confronted, it may raise its mane in an attempt to appear more menacing. It also emits a foulsmelling liquid from its anal glands.
Feeding
The aardwolf feeds primarily on termites and more specifically on Trinervitermes. This genus of termites has different species throughout the aardwolf's range. In East Africa, they eat Trinervitermes bettonianus, in central Africa, they eat Trinervitermes rhodesiensis, and in southern Africa, they eat T. trinervoides. Their technique consists of licking them off the ground as opposed to the aardvark, which digs into the mound. They locate their food by sound and also from the scent secreted by the soldier termites. An aardwolf may consume up to 250,000 termites per night using its long, sticky tongue.
They do not destroy the termite mound or consume the entire colony, thus ensuring that the t |
ermites can rebuild and provide a continuous supply of food. They often memorize the location of such nests and return to them every few months. During certain seasonal events, such as the onset of the rainy season and the cold of midwinter, the primary termites become scarce, so the need for other foods becomes pronounced. During these times, the southern aardwolf will seek out Hodotermes mossambicus, a type of harvester termite active in the afternoon, which explains some of their diurnal behavior in the winter. The eastern aardwolf, during the rainy season, subsists on termites from the genera Odontotermes and Macrotermes. They are also known to feed on other insects, larvae, eggs, and, some sources say, occasionally small mammals and birds, but these constitute a very small percentage of their total diet.
Unlike other hyenas, aardwolves do not scavenge or kill larger animals. Contrary to popular myths, aardwolves do not eat carrion, and if they are seen eating while hunched over a dead carcass, they are |
actually eating larvae and beetles. Also, contrary to some sources, they do not like meat, unless it is finely ground or cooked for them. The adult aardwolf was formerly assumed to forage in small groups, but more recent research has shown that they are primarily solitary foragers, necessary because of the scarcity of their insect prey. Their primary source, Trinervitermes, forages in small but dense patches of . While foraging, the aardwolf can cover about per hour, which translates to per summer night and per winter night.
Breeding
The breeding season varies depending on location, but normally takes place during autumn or spring. In South Africa, breeding occurs in early July. During the breeding season, unpaired male aardwolves search their own territory, as well as others, for a female to mate with. Dominant males also mate opportunistically with the females of less dominant neighboring aardwolves, which can result in conflict between rival males. Dominant males even go a step further and as the breed |
ing season approaches, they make increasingly greater and greater incursions onto weaker males' territories. As the female comes into oestrus, they add pasting to their tricks inside of the other territories, sometimes doing so more in rivals' territories than their own. Females will also, when given the opportunity, mate with the dominant male, which increases the chances of the dominant male guarding "his" cubs with her. Copulation lasts between 1 and 4.5 hours.
Gestation lasts between 89 and 92 days, producing two to five cubs most often two or three during the rainy season NovemberDecember, when termites are more active. They are born with their eyes open, but initially are helpless, and weigh around . The first six to eight weeks are spent in the den with their parents. The male may spend up to six hours a night watching over the cubs while the mother is out looking for food. After three months, they begin supervised foraging, and by four months are normally independent, though they often share a den wi |
th their mother until the next breeding season. By the time the next set of cubs is born, the older cubs have moved on. Aardwolves generally achieve sexual maturity at one and a half to two years of age.
Conservation
The aardwolf has not seen decreasing numbers and is relatively widespread throughout eastern Africa. They are not common throughout their range, as they maintain a density of no more than 1 per square kilometer, if food is abundant. Because of these factors, the IUCN has rated the aardwolf as least concern. In some areas, they are persecuted because of the mistaken belief that they prey on livestock; however, they are actually beneficial to the farmers because they eat termites that are detrimental. In other areas, the farmers have recognized this, but they are still killed, on occasion, for their fur. Dogs and insecticides are also common killers of the aardwolf.
Interaction with humans
Aardwolves are rare sights at zoos. Frankfurt Zoo in Germany was home to the oldest recorded aardwolf in cap |
tivity at 18 years and 11 months.
Notes
References
References
Further reading
External links
Animal Diversity Web
IUCN Hyaenidae Specialist Group Aardwolf pages on hyaenidae.org
Mammals described in 1783
Carnivorans of Africa
Hyenas
Mammals of Southern Africa
Fauna of East Africa
Myrmecophagous mammals
Taxa named by Anders Sparrman |
Adobe ; is a building material made from earth and organic materials, is Spanish for mudbrick. In some Englishspeaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of earthen construction, or various architectural styles like Pueblo Revival or Territorial Revival. Most adobe buildings are similar in appearance to cob and rammed earth buildings. Adobe is among the earliest building materials, and is used throughout the world.
Adobe architecture has been dated to before 5,100 B.C.
Description
Adobe bricks are rectangular prisms small enough that they can quickly air dry individually without cracking. They can be subsequently assembled, with the application of adobe mud to bond the individual bricks into a structure. There is no standard size, with substantial variations over the years and in different regions. In some areas a popular size measured weighing about ; in other contexts the size is weighing about . The maximum sizes can reach up to |
; above this weight it becomes difficult to move the pieces, and it is preferred to ram the mud in situ, resulting in a different typology known as rammed earth.
Strength
In dry climates, adobe structures are extremely durable, and account for some of the oldest existing buildings in the world. Adobe buildings offer significant advantages due to their greater thermal mass, but they are known to be particularly susceptible to earthquake damage if they are not reinforced. Cases where adobe structures were widely damaged during earthquakes include the 1976 Guatemala earthquake, the 2003 Bam earthquake, and the 2010 Chile earthquake.
Distribution
Buildings made of sundried earth are common throughout the world Middle East, Western Asia, North Africa, West Africa, South America, southwestern North America, Spain, and Eastern Europe. Adobe had been in use by indigenous peoples of the Americas in the Southwestern United States, Mesoamerica, and the Andes for several thousand years. Puebloan peoples built their ad |
obe structures with handsful or basketsful of adobe, until the Spanish introduced them to making bricks. Adobe bricks were used in Spain from the Late Bronze and Iron Ages eighth century BCE onwards. Its wide use can be attributed to its simplicity of design and manufacture, and economics.
Etymology
The word adobe has existed for around 4000 years with relatively little change in either pronunciation or meaning. The word can be traced from the Middle Egyptian c. 2000 BC word bt "mud brick" with vowels unwritten. Middle Egyptian evolved into Late Egyptian, Demotic or "preCoptic", and finally to Coptic c. 600 BC, where it appeared as tb. This was adopted into Arabic as aawbu or abu, with the definite article al attached. tuba, This was assimilated into the Old Spanish language as adobe , probably via Mozarabic. English borrowed the word from Spanish in the early 18th century, still referring to mudbrick construction.
In more modern English usage, the term "adobe" has come to include a style of architectur |
e popular in the desert climates of North America, especially in New Mexico, regardless of the construction method.
Composition
An adobe brick is a composite material made of earth mixed with water and an organic material such as straw or dung. The soil composition typically contains sand, silt and clay. Straw is useful in binding the brick together and allowing the brick to dry evenly, thereby preventing cracking due to uneven shrinkage rates through the brick. Dung offers the same advantage. The most desirable soil texture for producing the mud of adobe is 15 clay, 1030 silt, and 5575 fine sand. Another source quotes 1525 clay and the remainder sand and coarser particles up to cobbles , with no deleterious effect. Modern adobe is stabilized with either emulsified asphalt or Portland cement up to 10 by weight.
No more than half the clay content should be expansive clays, with the remainder nonexpansive illite or kaolinite. Too much expansive clay results in uneven drying through the brick, resulting in cr |
acking, while too much kaolinite will make a weak brick. Typically the soils of the Southwest United States, where such construction has been widely used, are an adequate composition.
Material properties
Adobe walls are load bearing, i.e. they carry their own weight into the foundation rather than by another structure, hence the adobe must have sufficient compressive strength. In the United States, most building codes call for a minimum compressive strength of 300 lbfin2 2.07 newtonmm2 for the adobe block. Adobe construction should be designed so as to avoid lateral structural loads that would cause bending loads. The building codes require the building sustain a 1 g lateral acceleration earthquake load. Such an acceleration will cause lateral loads on the walls, resulting in shear and bending and inducing tensile stresses. To withstand such loads, the codes typically call for a tensile modulus of rupture strength of at least 50 lbfin2 0.345 newtonmm2 for the finished block.
In addition to being an inexpen |
sive material with a small resource cost, adobe can serve as a significant heat reservoir due to the thermal properties inherent in the massive walls typical in adobe construction. In climates typified by hot days and cool nights, the high thermal mass of adobe mediates the high and low temperatures of the day, moderating the temperature of the living space. The massive walls require a large and relatively long input of heat from the sun radiation and from the surrounding air convection before they warm through to the interior. After the sun sets and the temperature drops, the warm wall will continue to transfer heat to the interior for several hours due to the timelag effect. Thus, a wellplanned adobe wall of the appropriate thickness is very effective at controlling inside temperature through the wide daily fluctuations typical of desert climates, a factor which has contributed to its longevity as a building material.
Thermodynamic material properties have significant variation in the literature. Some expe |
riments suggest that the standard consideration of conductivity is not adequate for this material, as its main thermodynamic property is inertia, and conclude that experimental tests should be performed over a longer period of time than usual preferably with changing thermal jumps. There is an effective Rvalue for a north facing 10in wall of R010 hr ft2 FBtu, which corresponds to thermal conductivity k10 in x 1 ft12 in R00.33 Btuhr ft F or 0.57 Wm K in agreement with the thermal conductivity reported from another source. To determine the total Rvalue of a wall, scale R0 by the thickness of the wall in inches. The thermal resistance of adobe is also stated as an Rvalue for a 10inch wall R04.1 hr ft2 FBtu. Another source provides the following properties conductivity0.30 Btuhr ft F or 0.52 Wm K; specific heat capacity0.24 Btulb F or 1 kJkg K and density106 lbft3 or 1700 kgm3, giving heat capacity25.4 Btuft3 F or 1700 kJm3 K. Using the average value of the thermal conductivity as k 32 Btuhr ft F or 0.55 Wm K, |
the thermal diffusivity is calculated to be 0.013 ft2h or 3.3x107 m2s.
Uses
Poured and puddled adobe walls
Poured and puddled adobe puddled clay, piled earth, today called cob, is made by placing soft adobe in layers, rather than by making individual dried bricks or using a form. "Puddle" is a general term for a clay or clay and sandbased material worked into a dense, plastic state. These are the oldest methods of building with adobe in the Americas until holes in the ground were used as forms, and later wooden forms used to make individual bricks were introduced by the Spanish.
Adobe bricks
Bricks made from adobe are usually made by pressing the mud mixture into an open timber frame. In North America, the brick is typically about in size. The mixture is molded into the frame, which is removed after initial setting. After drying for a few hours, the bricks are turned on edge to finish drying. Slow drying in shade reduces cracking.
The same mixture, without straw, is used to make mortar and often plaste |
r on interior and exterior walls. Some cultures used limebased cement for the plaster to protect against rain damage.
Depending on the form into which the mixture is pressed, adobe can encompass nearly any shape or size, provided drying is even and the mixture includes reinforcement for larger bricks. Reinforcement can include manure, straw, cement, rebar, or wooden posts. Straw, cement, or manure added to a standard adobe mixture can produce a stronger, more crackresistant brick. A test is done on the soil content first. To do so, a sample of the soil is mixed into a clear container with some water, creating an almost completely saturated liquid. The container is shaken vigorously for one minute. It is then allowed to settle for a day until the soil has settled into layers. Heavier particles settle out first, sand above, silt above that, and very fine clay and organic matter will stay in suspension for days. After the water has cleared, percentages of the various particles can be determined. Fifty to 60 per |
cent sand and 35 to 40 percent clay will yield strong bricks. The Cooperative State Research, Education, and Extension Service at New Mexico State University recommends a mix of not more than clay, not less than sand, and never more than silt.
During the Great Depression, designer and builder Hugh W. Comstock used cheaper materials and made a specialized adobe brick called "Bitudobe." His first adobe house was built in 1936. In 1948, he published the book PostAdobe; Simplified Adobe Construction Combining A Rugged Timber Frame And Modern Stabilized Adobe, which described his method of construction, including how to make "Bitudobe." In 1938, he served as an adviser to the architects Franklin Kump Associates, who built the Carmel High School, which used his Postadobe system.
Adobe wall construction
The ground supporting an adobe structure should be compressed, as the weight of adobe wall is significant and foundation settling may cause cracking of the wall. Footing depth is to be below the ground frost |
level. The footing and stem wall are commonly 24 and 14 inches thick, respectively. Modern construction codes call for the use of reinforcing steel in the footing and stem wall. Adobe bricks are laid by course. Adobe walls usually never rise above two stories as they are load bearing and adobe has low structural strength. When creating window and door openings, a lintel is placed on top of the opening to support the bricks above. Atop the last courses of brick, bond beams made of heavy wood beams or modern reinforced concrete are laid to provide a horizontal bearing plate for the roof beams and to redistribute lateral earthquake loads to shear walls more able to carry the forces. To protect the interior and exterior adobe walls, finishes such as mud plaster, whitewash or stucco can be applied. These protect the adobe wall from water damage, but need to be reapplied periodically. Alternatively, the walls can be finished with other nontraditional plasters that provide longer protection. Bricks made with stabil |
ized adobe generally do not need protection of plasters.
Adobe roof
The traditional adobe roof has been constructed using a mixture of soilclay, water, sand and organic materials. The mixture was then formed and pressed into wood forms, producing rows of dried earth bricks that would then be laid across a support structure of wood and plastered into place with more adobe.
Depending on the materials available, a roof may be assembled using wood or metal beams to create a framework to begin layering adobe bricks. Depending on the thickness of the adobe bricks, the framework has been preformed using a steel framing and a layering of a metal fencing or wiring over the framework to allow an even load as masses of adobe are spread across the metal fencing like cob and allowed to air dry accordingly. This method was demonstrated with an adobe blend heavily impregnated with cement to allow even drying and prevent cracking.
The more traditional flat adobe roofs are functional only in dry climates that are not expos |
ed to snow loads. The heaviest wooden beams, called vigas, lie atop the wall. Across the vigas lie smaller members called latillas and upon those brush is then laid. Finally, the adobe layer is applied.
To construct a flat adobe roof, beams of wood were laid to span the building, the ends of which were attached to the tops of the walls. Once the vigas, latillas and brush are laid, adobe bricks are placed. An adobe roof is often laid with bricks slightly larger in width to ensure a greater expanse is covered when placing the bricks onto the roof. Following each individual brick should be a layer of adobe mortar, recommended to be at least thick to make certain there is ample strength between the brick's edges and also to provide a relative moisture barrier during rain.
Roof design evolved around 1850 in the American Southwest. Three inches of adobe mud was applied on top of the latillas, then 18 inches of dry adobe dirt applied to the roof. The dirt was contoured into a low slope to a downspout aka a 'canal |
'. When moisture was applied to the roof the clay particles expanded to create a waterproof membrane. Once a year it was necessary to pull the weeds from the roof and reslope the dirt as needed.
Depending on the materials, adobe roofs can be inherently fireproof. The construction of a chimney can greatly influence the construction of the roof supports, creating an extra need for care in choosing the materials. The builders can make an adobe chimney by stacking simple adobe bricks in a similar fashion as the surrounding walls.
In 1927, the Uniform Building Code UBC was adopted in the United States. Local ordinances, referencing the UBC added requirements to building with adobe. These included restriction of building height of adobe structures to 1story, requirements for adobe mix compressive and shear strength and new requirements which stated that every building shall be designed to withstand seismic activity, specifically lateral forces. By the 1980s however, seismic related changes in the California Build |
ing Code effectively ended solid wall adobe construction in California; however PostandBeam adobe and veneers are still being used.
Adobe around the world
The largest structure ever made from adobe is the Arg Bam built by the Achaemenid Empire. Other large adobe structures are the Huaca del Sol in Peru, with 100 million signed bricks and the ciudellas of Chan Chan and Tambo Colorado, both in Peru.
See also
used adobe walls
waterproofing plaster
also known as Ctesiphon Arch in Iraq is the largest mud brick arch in the world, built beginning in 540 AD
References
External links
Soilbased building materials
Masonry
Adobe buildings and structures
Appropriate technology
Vernacular architecture
Sustainable building
Buildings and structures by construction material
Western genre staples and terminology |
An adventure is an exciting experience or undertaking that is typically bold, sometimes risky. Adventures may be activities with some potential for physical danger such as traveling, exploring, skydiving, mountain climbing, scuba diving, river rafting or participating in extreme sports. Adventures are often undertaken to create psychological arousal or in order to achieve a greater goal such as the pursuit of knowledge that can only be obtained in a risky manner.
Motivation
Adventurous experiences create psychological arousal, which can be interpreted as negative e.g. fear or positive e.g. flow. For some people, adventure becomes a major pursuit in and of itself. According to adventurer Andr Malraux, in his La Condition Humaine 1933, "If a man is not ready to risk his life, where is his dignity?".
Similarly, Helen Keller stated that "Life is either a daring adventure or nothing."
Outdoor adventurous activities are typically undertaken for the purposes of recreation or excitement examples are adventure rac |
ing and adventure tourism. Adventurous activities can also lead to gains in knowledge, such as those undertaken by explorers and pioneers the British adventurer Jason Lewis, for example, uses adventures to draw global sustainability lessons from living within finite environmental constraints on expeditions to share with schoolchildren. Adventure education intentionally uses challenging experiences for learning.
Author Jon Levy suggests that an experience should meet several criteria to be considered an adventure
Be remarkablethat is, worth talking about
Involve adversity or perceived risk
Bring about personal growth
Mythology and fiction
Some of the oldest and most widespread stories in the world are stories of adventure such as Homer's The Odyssey.
The knight errant was the form the "adventure seeker" character took in the late Middle Ages.
The adventure novel exhibits these "protagonist on adventurous journey" characteristics as do many popular feature films, such as Star Wars and Raiders of the Lo |
st Ark.
Outdoors
Adventure books may have the theme of the hero or main character going to face the wilderness or Mother Nature. Examples include books such as Hatchet or My Side of the Mountain. These books are less about "questing", such as in mythology or other adventure novels, but more about surviving on their own, living off the land, gaining new experiences, and becoming closer to the natural world.
Questing
Many adventures are based on the idea of a quest the hero goes off in pursuit of a reward, whether it be a skill, prize, treasure, or perhaps the safety of a person. On the way, the hero must overcome various obstacles to obtain their reward.
Video games
In videogame culture, an adventure game is a video game in which the player assumes the role of a protagonist in an interactive story driven by exploration and puzzlesolving. The genre's focus on story allows it to draw heavily from other narrativebased media, literature and film, encompassing a wide variety of literary genres. Many adventure |
games text and graphic are designed for a single player, since this emphasis on story and character makes multiplayer design difficult.
Nonfiction works
From ancient times, travelers and explorers have written about their adventures. Journals which became bestsellers in their day were written, such as Marco Polo's journal The Travels of Marco Polo or Mark Twain's Roughing It. Others were personal journals, only later published, such as the journals of Lewis and Clark or Captain James Cook's journals. There are also books written by those not directly a part of the adventure in question, such as The Right Stuff by Tom Wolfe or books written by those participating in the adventure but in a format other than that of a journal, such as Conquistadors of the Useless by Lionel Terray. Documentaries often use the theme of adventure as well.
Adventure sports
There are many sports classified as adventure games or sports, due to their inherent danger and excitement. Some of these include mountain climbing, skydiving |
, or other extreme sports.Adventure sports has fast caught up in the Indian milieu. India offers immense opportunity for adventure lovers throughout its length and breadth. Angling Fishing are two remarkable adventure activities among the many others that are offered in India. They are specially suited to the Indian subcontinent because of innumerable rivers that course through the expansive Gangetic Plains, and originate in the upper reaches of the magnificent Himalayas. The Indian Himalaya are an ultimate destination for adventure lovers and has attracted trekkers and lovers of nature Indian himalayas are the source of significant life giver rivers, like Ganges Beas, Satluj and their tributaries. The Himalayan mountain ranges of India offer breathtaking, highly challenging trekking routes. Mountaineering in India was introduced by the Europeans in the 18th century. India offers an exciting mountaineering experience to an adventure sport lover. The Himalayas that stretch from northwest of India to far north |
east offers a number of high rise peaks that are considered ideal for mountaineering. Some of the places for mountaineering in India are Leh Ladakh in Jammu and Kashmir, Garhwal and Kumaon Himalayas in Uttarakhand, Kullu valley and Lahul Spiti in Himachal Pradesh, and Sikkim and some other parts of northeastern region.
See also
Adventure film
Adventure playground
Adventure travel
Exploration
List of genres
Sports
Tourism
Travel
References
External links
Martin Feeney Going on a journey Life in Year 10
Website of the Research Unit "Philology of Adventure" ongoing research project on the literary history of the adventure pattern
What is an adventure? A definition of "adventure", "hero" and "epic" with an illustration of the hero's journey.
Wikivoyage |
Asia is Earth's largest and most populous continent, located primarily in the Eastern and Northern Hemispheres. It shares the continental landmass of Eurasia with the continent of Europe, and the continental landmass of AfroEurasia with Africa and Europe. Asia covers an area of , about 30 of Earth's total land area and 8.7 of the Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Its 4.7 billion people constituting roughly 60 of the world's population.
In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. It is somewhat arbitrary and has moved since its first conception in classical antiquity. The division of Eurasia into two continents reflects EastWest cultural, linguistic, a |
nd ethnic differences, some of which vary on a spectrum rather than with a sharp dividing line. The most commonly accepted boundaries place Asia to the east of the Suez Canal separating it from Africa; and to the east of the Turkish Straits, the Ural Mountains and Ural River, and to the south of the Caucasus Mountains and the Caspian and Black Seas, separating it from Europe.
China and India alternated in being the largest economies in the world from 1 to 1800 CE. China was a major economic power and attracted many to the east, and for many the legendary wealth and prosperity of the ancient culture of India personified Asia, attracting European commerce, exploration and colonialism. The accidental discovery of a transAtlantic route from Europe to America by Columbus while in search for a route to India demonstrates this deep fascination. The Silk Road became the main eastwest trading route in the Asian hinterlands while the Straits of Malacca stood as a major sea route. Asia has exhibited economic dynamism p |
articularly East Asia as well as robust population growth during the 20th century, but overall population growth has since fallen. Asia was the birthplace of most of the world's mainstream religions including Hinduism, Zoroastrianism, Judaism, Jainism, Buddhism, Confucianism, Taoism, Christianity, Islam, Sikhism, as well as many other religions.
Given its size and diversity, the concept of Asiaa name dating back to classical antiquitymay actually have more to do with human geography than physical geography. Asia varies greatly across and within its regions with regard to ethnic groups, cultures, environments, economics, historical ties and government systems. It also has a mix of many different climates ranging from the equatorial south via the hot desert in the Middle East, temperate areas in the east and the continental centre to vast subarctic and polar areas in Siberia.
Definition and boundaries
AsiaAfrica boundary
The boundary between Asia and Africa is the Red Sea, the Gulf of Suez, and the Suez Can |
al. This makes Egypt a transcontinental country, with the Sinai peninsula in Asia and the remainder of the country in Africa.
AsiaEurope boundary
The threefold division of the Old World into Europe, Asia and Africa has been in use since the 6th century BC, due to Greek geographers such as Anaximander and Hecataeus. Anaximander placed the boundary between Asia and Europe along the Phasis River the modern Rioni river in Georgia of Caucasus from its mouth by Poti on the Black Sea coast, through the Surami Pass and along the Kura River to the Caspian Sea, a convention still followed by Herodotus in the 5th century BC. During the Hellenistic period, this convention was revised, and the boundary between Europe and Asia was now considered to be the Tanais the modern Don River. This is the convention used by Roman era authors such as Posidonius, Strabo and Ptolemy.
The border between Asia and Europe was historically defined by European academics. The Don River became unsatisfactory to northern Europeans when Peter |
the Great, king of the Tsardom of Russia, defeating rival claims of Sweden and the Ottoman Empire to the eastern lands, and armed resistance by the tribes of Siberia, synthesized a new Russian Empire extending to the Ural Mountains and beyond, founded in 1721. The major geographical theorist of the empire was a former Swedish prisonerofwar, taken at the Battle of Poltava in 1709 and assigned to Tobolsk, where he associated with Peter's Siberian official, Vasily Tatishchev, and was allowed freedom to conduct geographical and anthropological studies in preparation for a future book.
In Sweden, five years after Peter's death, in 1730 Philip Johan von Strahlenberg published a new atlas proposing the Ural Mountains as the border of Asia. Tatishchev announced that he had proposed the idea to von Strahlenberg. The latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid19th century. The border had been moved perforce from |
the Black Sea to the Caspian Sea into which the Ural River projects. The border between the Black Sea and the Caspian is usually placed along the crest of the Caucasus Mountains, although it is sometimes placed further north.
AsiaOceania boundary
The border between Asia and the region of Oceania is usually placed somewhere in the Malay Archipelago. The Maluku Islands in Indonesia are often considered to lie on the border of southeast Asia, with New Guinea, to the east of the islands, being wholly part of Oceania. The terms Southeast Asia and Oceania, devised in the 19th century, have had several vastly different geographic meanings since their inception. The chief factor in determining which islands of the Malay Archipelago are Asian has been the location of the colonial possessions of the various empires there not all European. Lewis and Wigen assert, "The narrowing of 'Southeast Asia' to its present boundaries was thus a gradual process."
Ongoing definition
Geographical Asia is a cultural artifact of Eu |
ropean conceptions of the world, beginning with the Ancient Greeks, being imposed onto other cultures, an imprecise concept causing endemic contention about what it means. Asia does not exactly correspond to the cultural borders of its various types of constituents.
From the time of Herodotus a minority of geographers have rejected the threecontinent system Europe, Africa, Asia on the grounds that there is no substantial physical separation between them. For example, Sir Barry Cunliffe, the emeritus professor of European archeology at Oxford, argues that Europe has been geographically and culturally merely "the western excrescence of the continent of Asia".
Geographically, Asia is the major eastern constituent of the continent of Eurasia with Europe being a northwestern peninsula of the landmass. Asia, Europe and Africa make up a single continuous landmassAfroEurasia except for the Suez Canaland share a common continental shelf. Almost all of Europe and a major part of Asia sit atop the Eurasian Plate, adjo |
ined on the south by the Arabian and Indian Plate and with the easternmost part of Siberia east of the Chersky Range on the North American Plate.
Etymology
The idea of a place called "Asia" was originally a concept of Greek civilization, though this might not correspond to the entire continent currently known by that name. The English word comes from Latin literature, where it has the same form, "Asia". Whether "Asia" in other languages comes from Latin of the Roman Empire is much less certain, and the ultimate source of the Latin word is uncertain, though several theories have been published. One of the first classical writers to use Asia as a name of the whole continent was Pliny. This metonymical change in meaning is common and can be observed in some other geographical names, such as Scandinavia from Scania.
Bronze Age
Before Greek poetry, the Aegean Sea area was in a Greek Dark Age, at the beginning of which syllabic writing was lost and alphabetic writing had not begun. Prior to then in the Bronze Ag |
e the records of the Assyrian Empire, the Hittite Empire and the various Mycenaean states of Greece mention a region undoubtedly Asia, certainly in Anatolia, including if not identical to Lydia. These records are administrative and do not include poetry.
The Mycenaean states were destroyed about 1200 BCE by unknown agents, though one school of thought assigns the Dorian invasion to this time. The burning of the palaces caused the clay tablets holding the Mycenaean administrative records to be preserved by baking. These tablets were written in a Greek syllabic script called Linear B. This script was deciphered by a number of interested parties, most notably by a young World War II cryptographer, Michael Ventris, subsequently assisted by the scholar, John Chadwick.
A major cache discovered by Carl Blegen at the site of ancient Pylos included hundreds of male and female names formed by different methods. Some of these are of women held in servitude as study of the society implied by the content reveals. They |
were used in trades, such as clothmaking, and usually came with children. The epithet lawiaiai, "captives", associated with some of them identifies their origin. Some are ethnic names. One in particular, aswiai, identifies "women of Asia". Perhaps they were captured in Asia, but some others, Milatiai, appear to have been of Miletus, a Greek colony, which would not have been raided for slaves by Greeks. Chadwick suggests that the names record the locations where these foreign women were purchased. The name is also in the singular, Aswia, which refers both to the name of a country and to a female from there. There is a masculine form, . This Aswia appears to have been a remnant of a region known to the Hittites as Assuwa, centered on Lydia, or "Roman Asia". This name, Assuwa, has been suggested as the origin for the name of the continent "Asia". The Assuwa league was a confederation of states in western Anatolia, defeated by the Hittites under Tudhaliya I around 1400 BCE.
Classical antiquity
Latin Asia and Gr |
eek appear to be the same word. Roman authors translated as Asia. The Romans named a province Asia, located in western Anatolia in modernday Turkey. There was an Asia Minor and an Asia Major located in modernday Iraq. As the earliest evidence of the name is Greek, it is likely circumstantially that Asia came from , but ancient transitions, due to the lack of literary contexts, are difficult to catch in the act. The most likely vehicles were the ancient geographers and historians, such as Herodotus, who were all Greek. Ancient Greek certainly evidences early and rich uses of the name.
The first continental use of Asia is attributed to Herodotus about 440 BCE, not because he innovated it, but because his Histories are the earliest surviving prose to describe it in any detail. He defines it carefully, mentioning the previous geographers whom he had read, but whose works are now missing. By it he means Anatolia and the Persian Empire, in contrast to Greece and Egypt.
Herodotus comments that he is puzzled as t |
o why three women's names were "given to a tract which is in reality one" Europa, Asia, and Libya, referring to Africa, stating that most Greeks assumed that Asia was named after the wife of Prometheus i.e. Hesione, but that the Lydians say it was named after Asies, son of Cotys, who passed the name on to a tribe at Sardis. In Greek mythology, "Asia" or "Asie" was the name of a "Nymph or Titan goddess of Lydia".
In ancient Greek religion, places were under the care of female divinities, parallel to guardian angels. The poets detailed their doings and generations in allegoric language salted with entertaining stories, which subsequently playwrights transformed into classical Greek drama and became "Greek mythology". For example, Hesiod mentions the daughters of Tethys and Ocean, among whom are a "holy company", "who with the Lord Apollo and the Rivers have youths in their keeping". Many of these are geographic Doris, Rhodea, Europa, Asia. Hesiod explains
The Iliad attributed by the ancient Greeks to Homer |
mentions two Phrygians the tribe that replaced the Luvians in Lydia in the Trojan War named Asios an adjective meaning "Asian"; and also a marsh or lowland containing a marsh in Lydia as . According to many Muslims, the term came from Ancient Egypt's Queen Asiya, the adoptive mother of Moses.
History
The history of Asia can be seen as the distinct histories of several peripheral coastal regions East Asia, South Asia, Southeast Asia and the Middle East, linked by the interior mass of the Central Asian steppes.
The coastal periphery was home to some of the world's earliest known civilizations, each of them developing around fertile river valleys. The civilizations in Mesopotamia, the Indus Valley and the Yellow River shared many similarities. These civilizations may well have exchanged technologies and ideas such as mathematics and the wheel. Other innovations, such as writing, seem to have been developed individually in each area. Cities, states and empires developed in these lowlands.
The central steppe r |
egion had long been inhabited by horsemounted nomads who could reach all areas of Asia from the steppes. The earliest postulated expansion out of the steppe is that of the IndoEuropeans, who spread their languages into the Middle East, South Asia, and the borders of China, where the Tocharians resided. The northernmost part of Asia, including much of Siberia, was largely inaccessible to the steppe nomads, owing to the dense forests, climate and tundra. These areas remained very sparsely populated.
The center and the peripheries were mostly kept separated by mountains and deserts. The Caucasus and Himalaya mountains and the Karakum and Gobi deserts formed barriers that the steppe horsemen could cross only with difficulty. While the urban city dwellers were more advanced technologically and socially, in many cases they could do little in a military aspect to defend against the mounted hordes of the steppe. However, the lowlands did not have enough open grasslands to support a large horsebound force; for this a |
nd other reasons, the nomads who conquered states in China, India, and the Middle East often found themselves adapting to the local, more affluent societies.
The Islamic Caliphate's defeats of the Byzantine and Persian empires led to West Asia and southern parts of Central Asia and western parts of South Asia under its control during its conquests of the 7th century. The Mongol Empire conquered a large part of Asia in the 13th century, an area extending from China to Europe. Before the Mongol invasion, Song dynasty reportedly had approximately 120 million citizens; the 1300 census which followed the invasion reported roughly 60 million people.
The Black Death, one of the most devastating pandemics in human history, is thought to have originated in the arid plains of central Asia, where it then travelled along the Silk Road.
The Russian Empire began to expand into Asia from the 17th century, and would eventually take control of all of Siberia and most of Central Asia by the end of the 19th century. The Otto |
man Empire controlled Anatolia, most of the Middle East, North Africa and the Balkans from the mid 16th century onwards. In the 17th century, the Manchu conquered China and established the Qing dynasty. The Islamic Mughal Empire and the Hindu Maratha Empire controlled much of India in the 16th and 18th centuries respectively. The Empire of Japan controlled most of East Asia and much of Southeast Asia, New Guinea and the Pacific islands until the end of World War II.
Geography and climate
Asia is the largest continent on Earth. It covers 9 of the Earth's total surface area or 30 of its land area, and has the longest coastline, at . Asia is generally defined as comprising the eastern fourfifths of Eurasia. It is located to the east of the Suez Canal and the Ural Mountains, and south of the Caucasus Mountains or the KumaManych Depression and the Caspian and Black Seas. It is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean and on the north by the Arctic Ocean. Asia is subdivided into |
49 countries, five of them Georgia, Azerbaijan, Russia, Kazakhstan and Turkey are transcontinental countries lying partly in Europe. Geographically, Russia is partly in Asia, but is considered a European nation, both culturally and politically.
The Gobi Desert is in Mongolia and the Arabian Desert stretches across much of the Middle East. The Yangtze River in China is the longest river in the continent. The Himalayas between Nepal and China is the tallest mountain range in the world. Tropical rainforests stretch across much of southern Asia and coniferous and deciduous forests lie farther north.
Main regions
There are various approaches to the regional division of Asia. The following subdivision into regions is used, among others, by the UN statistics agency UNSD. This division of Asia into regions by the United Nations is done solely for statistical reasons and does not imply any assumption about political or other affiliations of countries and territories.
North Asia Siberia
Central Asia The 'stans
We |
stern Asia The Middle East or Near East
South Asia Indian subcontinent
East Asia Far East
Southeast Asia East Indies and Indochina
Climate
Asia has extremely diverse climate features. Climates range from arctic and subarctic in Siberia to tropical in southern India and Southeast Asia. It is moist across southeast sections, and dry across much of the interior. Some of the largest daily temperature ranges on Earth occur in western sections of Asia. The monsoon circulation dominates across southern and eastern sections, due to the presence of the Himalayas forcing the formation of a thermal low which draws in moisture during the summer. Southwestern sections of the continent are hot. Siberia is one of the coldest places in the Northern Hemisphere, and can act as a source of arctic air masses for North America. The most active place on Earth for tropical cyclone activity lies northeast of the Philippines and south of Japan.
A survey carried out in 2010 by global risk analysis farm Maplecroft identified 16 c |
ountries that are extremely vulnerable to climate change. Each nation's vulnerability was calculated using 42 socio, economic and environmental indicators, which identified the likely climate change impacts during the next 30 years. The Asian countries of Bangladesh, India, the Philippines, Vietnam, Thailand, Pakistan, China and Sri Lanka were among the 16 countries facing extreme risk from climate change. Some shifts are already occurring. For example, in tropical parts of India with a semiarid climate, the temperature increased by 0.4 C between 1901 and 2003.
A 2013 study by the International Crops Research Institute for the SemiArid Tropics ICRISAT aimed to find sciencebased, propoor approaches and techniques that would enable Asia's agricultural systems to cope with climate change, while benefitting poor and vulnerable farmers. The study's recommendations ranged from improving the use of climate information in local planning and strengthening weatherbased agroadvisory services, to stimulating diversificat |
ion of rural household incomes and providing incentives to farmers to adopt natural resource conservation measures to enhance forest cover, replenish groundwater and use renewable energy.
The ten countries of the Association of Southeast Asian Nations ASEAN Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam are among the most vulnerable to the effects of climate change in the world, however, ASEAN's climate mitigation efforts are not commensurate with the climate threats and risks it faces.
Economy
Asia has the largest continental economy by both GDP Nominal and PPP in the world, and is the fastest growing economic region. , the largest economies in Asia are China, Japan, India, South Korea, Indonesia and Turkey based on GDP in both nominal and PPP. Based on Global Office Locations 2011, Asia dominated the office locations with 4 of the top 5 being in Asia Hong Kong, Singapore, Tokyo and Seoul. Around 68 percent of international firms have an office in |
Hong Kong.
In the late 1990s and early 2000s, the economies of China and India have been growing rapidly, both with an average annual growth rate of more than 8. Other recent veryhighgrowth nations in Asia include Israel, Malaysia, Indonesia, Bangladesh, Thailand, Vietnam, and the Philippines, and mineralrich nations such as Kazakhstan, Turkmenistan, Iran, Brunei, the United Arab Emirates, Qatar, Kuwait, Saudi Arabia, Bahrain and Oman.
According to economic historian Angus Maddison in his book The World Economy A Millennial Perspective, India had the world's largest economy during 0 BCE and 1000 BCE. Historically, India was the largest economy in the world for most of the two millennia from the 1st until 19th century, contributing 25 of the world's industrial output. China was the largest and most advanced economy on earth for much of recorded history and shared the mantle with India. For several decades in the late twentieth century Japan was the largest economy in Asia and secondlargest of any single nat |
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