Hominidae
- For an explanation of very similar terms see Hominid.
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The hominids are the members of the biological family Hominidae (the great apes), which includes humans, chimpanzees, gorillas, and orangutans.
This classification has been revised several times in the last few decades. Originally, the group was restricted to humans and their extinct relatives, with the other great apes being placed in a separate family, the Pongidae. This definition is still used by many anthropologists and by lay people. However, that definition makes Pongidae paraphyletic, whereas most taxonomists nowadays encourage monophyletic groups. Thus many biologists consider Hominidae to include the Pongidae as the subfamily Ponginae, or restrict the latter to the orangutan and extinct relatives like Gigantopithecus. The taxonomy shown here follows the monophyletic groupings.
Especially close human relatives form a subfamily, the Homininae. Some researchers go so far as to include chimpanzees and gorillas in the genus Homo along with humans, but most genetic evidence suggests the relationships as shown here.
Many extinct hominids have been studied to help understand the relationship between modern humans and the other extant hominids. Some of the extinct members of this family include Gigantopithecus, Orrorin, Ardipithecus, Kenyanthropus, and the australopithecines Australopithecus and Paranthropus.
The exact criteria for membership in the Homininae are not clear, but the family generally includes those species who share more than 97% of their DNA with the modern human genome, and exhibit a capacity for language and for simple cultures beyond the family or band. The theory of mind, providing the capacity to lie convincingly, is a controversial criterion distinguishing the adult human alone among the hominids. Humans acquire this capacity at about four and a half years of age, whereas the bonobo, gorilla and chimpanzee never seem to do so. However, without the ability to test whether early members of the Homininae (such as Homo erectus, Homo neanderthalensis, or even the australopithecines) had a theory of mind, it is difficult to ignore similarities seen in their living cousins. Despite an apparent lack of real culture and significant physiological differences, some say that the orangutan may also satisfy these criteria. These scientific debates take on political significance for advocates of Great Ape personhood.
In 2002, a 6–7 million year old fossil skull nicknamed "Toumaï" by its discoverers, and formally classified as Sahelanthropus tchadensis, was discovered in Chad and is possibly the earliest hominid fossil ever found. In addition to its age, Toumaï, unlike the 3–4 million year younger gracile australopithecine dubbed "Lucy", has a relatively flat face without the prominent snout seen on other pre-Homo hominids. Some researchers have made the suggestion that this previously unknown species may in fact be a direct ancestor of modern humans (or at least closely related to a direct ancestor). Others contend that one fossil is not enough to make such a claim because it would overturn the conclusions of over 100 years of anthropological study. A report on this finding was published in the journal Nature on July 11, 2002. While some scientists claim that it is merely the skull of a female gorilla, others have called it the most important hominin fossil since Australopithecus.
Classification
- Family Hominidae: humans and other great apes
- Subfamily Ponginae
- Genus Pongo
- Bornean Orangutan, Pongo pygmaeus
- Sumatran Orangutan, Pongo abelii
- Genus Pongo
- Subfamily Homininae
- Subfamily Ponginae
See also
- Ape extinction
- Declaration on Great Apes
- Evolution of Homo sapiens
- Evolutionary neuroscience
- Graphical timeline of human evolution
- Great ape language
- Great Ape Project
- List of apes - notable individual apes
- The Mind of an Ape
- Great Ape research ban
External links
- NPR News: Toumaï the Human Ancestor
- Hominid Species at talkorigins.org
- For more details on Hominid species, including excellent photos of fossil hominids
- A Classification A more complete classification than the above, with a list of species, including extinct ones. Extensive, though still incomplete.
