Homo (genus)

Overview
Homo is the genus that includes modern humans and their close relatives. The genus is estimated to be about 2.5 million years old, evolving from Australopithecine ancestors with the appearance of Homo habilis. Appearance of Homo coincides with the first evidence of stone tools (the Oldowan industry), and thus by definition with the beginning of the Lower Paleolithic.



All species except Homo sapiens (modern humans) are extinct. Homo neanderthalensis, traditionally considered the last surviving relative, died out 24,000 years ago while a recent discovery suggests that another species, Homo floresiensis, may have lived as recently as 12,000 years ago.

A minority of zoologists consider that the two species of chimpanzees (usually treated in the genus Pan), and maybe the gorillas (usually treated in the genus Gorilla) should also be included in the genus based on genetic similarities. Most scientists argue that chimpanzees and gorillas have too many anatomical differences between themselves and humans to be part of Homo. Given the large number of morphological similarities exhibited, Homo is closely related to several extinct hominin genera, most notably Kenyanthropus, Paranthropus and Australopithecus. As of 2007, there is no universally accepted recognition of which taxa Homo radiated from.

The word homo is Latin for "man", in the original sense of "human being", or "person". The word "human" itself is from Latin humanus, an adjective cognate to homo, both derived from Proto-Indo-European language  "earth". Cf. Hebrew adam, meaning "human", cognate to adamah, meaning "ground". (And cf. Latin humus, meaning "soil".)

Species

 * †Homo habilis (Handy Man)
 * †Homo rudolfensis (Rudolf Man)
 * †Homo ergaster (Working Man)
 * †Homo erectus (Upright Man)
 * †Homo floresiensis (Flores Man; discovered 2003. Species status remains under debate.)
 * †Homo antecessor (Predecessor Man)
 * †Homo heidelbergensis (Heidelberg Man)
 * †Homo neanderthalensis (Neanderthal Man)
 * †Homo rhodesiensis (Rhodesia Man)
 * †Homo cepranensis (Ceprano Man)
 * †Homo georgicus (Georgia Man)
 * Homo sapiens
 * †Homo sapiens idaltu (elderly wise man &mdash; discovered 1997)
 * Homo sapiens sapiens (Wise Man; modern humans)

H. heidelbergensis and H. neanderthalensis are closely related to each other and have been considered to be subspecies of H. sapiens, but analysis of mitochondrial DNA from Homo neanderthalensis fossils shows that H. neanderthalensis is more closely related to chimpanzees than H. sapiens is, thereby suggesting that H. sapiens is the more derived of the two. H. rhodesiensis and H. cepranensis are also more closely related to each other than to the other species.