Changes

==Physiology==

==Physiology==

A full grown adult male chimpanzee can weigh from 35-70 kilograms (75-155 pounds) and stand 0.9-1.2 meters (3-4 feet) tall, while females usually weigh 26-50 kg (57-110 pounds) and stand 0.66-1 meters (2.0-3.5 feet) tall.

A full grown adult male chimpanzee can weigh from 35-70 kilograms (75-155 pounds) and stand 0.9-1.2 meters (3–4 feet) tall, while females usually weigh 26–50 kg (57-110 pounds) and stand 0.66–1 meters (2.0-3.5 feet) tall.

Chimpanzees have both opposable big toes and opposable thumbs. Most primates have nine wrist bones. Humans, chimps and gorillas have eight; two have fused, stabilising the wrist for knuckle-walking.

Chimpanzees have both opposable big toes and opposable thumbs. Most primates have nine wrist bones. Humans, chimps and gorillas have eight; two have fused, stabilising the wrist for knuckle-walking.

==Social organization==

==Social organization==

Chimps travel in small, frequently-changing groups. Larger groups gather around food or an attractive female. Different groups use different tools. Some "fish" for termites with twigs; others crack nuts with rocks or sharpen spears with their teeth to hunt bush-babies. <ref>http://news.bbc.co.uk/1/hi/sci/tech/6387611.stm</ref>

Chimps travel in small, frequently-changing groups. Larger groups gather around food or an attractive female. Different groups use different tools. Some "fish" for termites with twigs; others crack nuts with rocks or sharpen spears with their teeth to hunt bush-babies.<ref>http://news.bbc.co.uk/1/hi/sci/tech/6387611.stm</ref>

Males co-operate in hunting and share meat afterwards. Although chimps like meat, it forms only 2% of their diet. Bonobos rarely eat it, and both species prefer fruit. Hunts mainly happen during food shortages or for mating displays.

Males co-operate in hunting and share meat afterwards. Although chimps like meat, it forms only 2% of their diet. Bonobos rarely eat it, and both species prefer fruit. Hunts mainly happen during food shortages or for mating displays.

==Chimpanzee differences==

==Chimpanzee differences==

Anatomical differences between Common and Pygmy Chimpanzees are slight, but in [[sex|sexual]] and social behavior there are marked differences. Common Chimpanzees have an [[omnivore|omnivorous]] [[diet (nutrition)|diet]], a troop [[predation|hunting]] culture based on beta males led by an [[alpha male]], and highly complex social relationships. Bonobos, on the other hand, have a mostly [[herbivorous]] diet and an [[egalitarian]], [[matriarchal]], sexually receptive behavior. The exposed skin of the face, hands and feet varies from pink to very dark in both species, but is generally lighter in younger individuals, darkening as maturity is reached. Bonobos have longer arms and tend to walk upright more often than the Common Chimpanzee.{{fact}}

Anatomical differences between Common and Pygmy Chimpanzees are slight, but in [[sex]]ual and social behavior there are marked differences. Common Chimpanzees have an [[omnivore|omnivorous]] [[diet (nutrition)|diet]], a troop [[predation|hunting]] culture based on beta males led by an [[alpha male]], and highly complex social relationships. Bonobos, on the other hand, have a mostly [[herbivorous]] diet and an [[egalitarian]], [[matriarchal]], sexually receptive behavior. The exposed skin of the face, hands and feet varies from pink to very dark in both species, but is generally lighter in younger individuals, darkening as maturity is reached. Bonobos have longer arms and tend to walk upright more often than the Common Chimpanzee.{{fact}}

Among bonobos, females have low-key dominance, priority over eating and solidarity against male aggression. Bonobos use sex in all its permutations to alleviate tension or for appeasement; it’s casual and quick (average 13 seconds) and not necessarily driven by orgasm or reproduction. Anything that arouses the interest of more than one bonobo results in sexual contact. Unlike common chimps, bonobos often have sex face to face. Despite constant sexual activity, reproductive rates are similar to common chimps. Males stay near their mothers all their lives. High-ranking males are usually sons of important females.<ref>http://www.janegoodall.org/chimp_central/chimpanzees/</ref>  

Among bonobos, females have low-key dominance, priority over eating and solidarity against male aggression. Bonobos use sex in all its permutations to alleviate tension or for appeasement; it’s casual and quick (average 13 seconds) and not necessarily driven by orgasm or reproduction. Anything that arouses the interest of more than one bonobo results in sexual contact. Unlike common chimps, bonobos often have sex face to face. Despite constant sexual activity, reproductive rates are similar to common chimps. Males stay near their mothers all their lives. High-ranking males are usually sons of important females.<ref>http://www.janegoodall.org/chimp_central/chimpanzees/</ref>  

==Are chimpanzees related to humans?==

==Are chimpanzees related to humans?==

The genus ''Pan'' is now considered to be part of the subfamily [[Hominidae]] to which [[human]]s also belong. [[Theory of evolution|Evolutionary]] [[Biology|biologists]] believe that the two species of chimpanzees are the closest living [[evolution|evolutionary]] relatives to humans. It is thought that humans shared a common ancestor with chimpanzees and gorillas as recently as [[Pliocene|four]] to [[Miocene|seven million years ago]]. Groundbreaking research by [[Mary-Claire King]] in 1973 found 99% identical [[DNA]] between human beings and chimpanzees,<ref>Mary-Claire King, ''Protein polymorphisms in chimpanzee and human evolution'', Doctoral dissertation, University of California, Berkeley (1973).</ref> although research since has modified that finding to about 94% commonality,<ref name=ns>{{cite web | url = http://www.sciam.com/article.cfm?chanID=sa003&articleID=9D0DAC2B-E7F2-99DF-3AA795436FEF8039 |date = 2006-12-19 | title = Humans and Chimps: Close But Not That Close | publisher = Scientific American | accessdate = 2006-12-20}}</ref> with at least some of the difference occurring in "junk" DNA. It has even been proposed that ''troglodytes'' and ''paniscus'' belong with ''sapiens'' in the genus ''[[Homo (genus)|Homo]]'', rather than in ''Pan''. One argument for this is that other species have been reclassified to belong to the same genus on the basis of less genetic similarity than that between humans and chimpanzees. Indeed cladistic taxonomy, based on both genetic difference and date of likely divergence, is very clear in placing both extant species of ''Pan'' in the genus ''Homo'', mainly because the genus ''Homo'' takes precedence on account of being coined first. It is very important, however, to consider where the differences in the genome appear.<ref>http://www.sciencedaily.com/releases/2006/12/061219201931.htm</ref>

The genus ''Pan'' is now considered to be part of the subfamily [[Hominidae]] to which [[human]]s also belong. [[Theory of evolution|Evolutionary]] [[Biology|biologists]] believe that the two species of chimpanzees are the closest living [[evolution]]ary relatives to humans. It is thought that humans shared a common ancestor with chimpanzees and gorillas as recently as [[Pliocene|four]] to [[Miocene|seven million years ago]]. Groundbreaking research by [[Mary-Claire King]] in 1973 found 99% identical [[DNA]] between human beings and chimpanzees,<ref>Mary-Claire King, ''Protein polymorphisms in chimpanzee and human evolution'', Doctoral dissertation, University of California, Berkeley (1973).</ref> although research since has modified that finding to about 94% commonality,<ref name=ns>{{cite web | url = http://www.sciam.com/article.cfm?chanID=sa003&articleID=9D0DAC2B-E7F2-99DF-3AA795436FEF8039 |date = 2006-12-19 | title = Humans and Chimps: Close But Not That Close | publisher = Scientific American | accessdate = 2006-12-20}}</ref> with at least some of the difference occurring in "junk" DNA. It has even been proposed that ''troglodytes'' and ''paniscus'' belong with ''sapiens'' in the genus ''[[Homo (genus)|Homo]]'', rather than in ''Pan''. One argument for this is that other species have been reclassified to belong to the same genus on the basis of less genetic similarity than that between humans and chimpanzees. Indeed cladistic taxonomy, based on both genetic difference and date of likely divergence, is very clear in placing both extant species of ''Pan'' in the genus ''Homo'', mainly because the genus ''Homo'' takes precedence on account of being coined first. It is very important, however, to consider where the differences in the genome appear.<ref>http://www.sciencedaily.com/releases/2006/12/061219201931.htm</ref>

Most biologists hold the view that chimpanzees and humans share a close common ancestor due to molecular, morphological, physiological, geographical and behavioral similarities. Although in some cases [[convergent evolution]] makes for such similarities in distantly related organisms the similarities between humans and chimps include neutral genetic markers that could not be subject to convergent evolution.<ref> A. Hobolth et al. (2007) Genomic relationships and speciation times of human, chimpanzee, and gorilla inferred from a coalescent hidden Markov model. ''PLOS Genetics'' '''23:'''e7</ref>

Most biologists hold the view that chimpanzees and humans share a close common ancestor due to molecular, morphological, physiological, geographical and behavioral similarities. Although in some cases [[convergent evolution]] makes for such similarities in distantly related organisms the similarities between humans and chimps include neutral genetic markers that could not be subject to convergent evolution.<ref>A. Hobolth et al. (2007) Genomic relationships and speciation times of human, chimpanzee, and gorilla inferred from a coalescent hidden Markov model. ''PLOS Genetics'' '''23:'''e7</ref>

A study published by Clark and Nielsen of [[Cornell University]] in the December 2003 issue of the journal ''[[Science (journal)|Science]]'' highlights differences related to one of humankind's defining qualities &ndash; the ability to understand [[language]] and to communicate through speech. These macro-phenotypic differences, however, may owe less to physiology than might be assumed given that ''Homo sapiens'' developed modern cultural features long after the modern physiological features were in place and indeed competed averagely against other species of ''Homo'' with regard to tools, etc. for many millennia. Differences also exist in the genes for smell, in genes that regulate the metabolism of amino acids and in genes that may affect the ability to digest various proteins.  

A study published by Clark and Nielsen of [[Cornell University]] in the December 2003 issue of the journal ''[[Science (journal)|Science]]'' highlights differences related to one of humankind's defining qualities &ndash; the ability to understand [[language]] and to communicate through speech. These macro-phenotypic differences, however, may owe less to physiology than might be assumed given that ''Homo sapiens'' developed modern cultural features long after the modern physiological features were in place and indeed competed averagely against other species of ''Homo'' with regard to tools, etc. for many millennia. Differences also exist in the genes for smell, in genes that regulate the metabolism of amino acids and in genes that may affect the ability to digest various proteins.  

===Fossils===

===Fossils===

Many [[Human evolution|human fossils]] have been found, but chimpanzee fossils were not described until 2005. Existing chimpanzee populations in West and Central Africa do not overlap with the major human fossil sites in East Africa. However, chimpanzee fossils have now been reported from [[Kenya]]. The [[Theory of evolution|evolutionist]] researchers who discovered them asserted: "These fossils, from the Kapthurin Formation, Kenya, show that representatives of ''Pan'' were present in the East African Rift Valley during the Middle Pleistocene, where they were contemporary with an extinct species of ''Homo''."<ref>McBrearty, S. and N. G. Jablonksi (2005), "First fossil chimpanzee," ''Nature'' '''437'''(7055):105-8. [http://www.ncbi.nlm.nih.gov/entrez/ Entrez PubMed], search on PMID: 16136135</ref>.

Many [[Human evolution|human fossils]] have been found, but chimpanzee fossils were not described until 2005. Existing chimpanzee populations in West and Central Africa do not overlap with the major human fossil sites in East Africa. However, chimpanzee fossils have now been reported from [[Kenya]]. The [[Theory of evolution|evolutionist]] researchers who discovered them asserted: "These fossils, from the Kapthurin Formation, Kenya, show that representatives of ''Pan'' were present in the East African Rift Valley during the Middle Pleistocene, where they were contemporary with an extinct species of ''Homo''.".<ref>McBrearty, S. and N. G. Jablonksi (2005), "First fossil chimpanzee," ''Nature'' '''437'''(7055):105-8. [http://www.ncbi.nlm.nih.gov/entrez/ Entrez PubMed], search on PMID 16136135</ref>

==Notes and references==

==Notes and references==