Chimpanzee

Pan troglodytes

Taxonomic relationships

The genus Pan is now considered to be part of the subfamily Homininae to which humans also belong. Biologists believe that the two species of chimpanzees are the closest living evolutionary relatives to humans. Their common ancestor branched off from its latest common ancestor with us as recently as four to seven million years ago, and they have about 95 to 98 percent of their DNA in common with humans. It has even been proposed that chimpanzees should be recategorized in the genus Homo as well. The 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. However, it is very important where the differences in the genome appear. The study published by Clark and Nielsen of the Cornell University in the Science in December 2003 highlights differences related to one of humankind?s defining qualities ? the ability to understand language and to communicate through speech, also in the genes for smell, in genes that enable humans and chimps to metabolize amino acids and in genes that may affect the ability to digest various protein. The fact that many chimpanzees have been taught to use hundreds of sign language words, and have sometimes passed on this knowledge to their offspring, indicates that "language" may not be such a major divider between humans and other hominids. See the history of hominoid taxonomy for more about the history of the classification of chimpanzees.

Related Topics:
Homininae - Human - Biologists - Evolutionary - Four - Seven million years ago - DNA - Homo - Cornell University - Science - 2003 - Language - History of hominoid taxonomy

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Fossils

Many human fossils have been found, but chimpanzee fossils had not been 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 in Kenya. This result indicates that both humans and members of the Pan clade were present in the East African Rift Valley during the Middle Pleistocene.{{ref|firstfossil}}

Related Topics:
Human fossils - Kenya - Clade - Rift Valley - Pleistocene

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References

• {{note|firstfossil}} "First fossil chimpanzee." by S. McBrearty and N. G. Jablonski in Nature (2005) Sep 1, Volume 437 pages 105-108. {{Entrez Pubmed|16136135}}.
• {{note|goodall}} Goodall, Jane. (1986) The Chimpanzees of Gombe: Patterns of Behavior.
• Pickrell, John. (September 24, 2002). Humans, Chimps Not as Closely Related as Thought?. National Geographic.