Homo (from Latin homō 'man') is the genus that emerged in the (otherwise extinct) genus Australopithecus that encompasses the extant species Homo sapiens (modern humans), plus several extinct species classified as either ancestral to or closely related to modern humans (depending on the species), most notably Homo erectus and Homo neanderthalensis. The genus emerged with the appearance of Homo habilis just over 2 million years ago.[a]Homo, together with the genus Paranthropus, is probably sister to Australopithecus africanus, which itself had previously split from the lineage of Pan, the chimpanzees.[b][4][5]
Homo erectus appeared about 2 million years ago and, in several early migrations, spread throughout Africa (where it is dubbed Homo ergaster) and Eurasia. It was likely the first human species to live in a hunter-gatherer society and to control fire. An adaptive and successful species, Homo erectus persisted for more than a million years and gradually diverged into new species by around 500,000 years ago.[c][6]
Anatomically modern humans (Homo sapiens) emerged close to 300,000 to 200,000 years ago,[7] in Africa, and Homo neanderthalensis emerged around the same time in Europe and Western Asia. Homo sapiens dispersed from Africa in several waves, from possibly as early as 250,000 years ago, and certainly by 130,000 years ago, the so-called Southern Dispersal beginning about 70–50,000 years ago[8][9][10] leading to the lasting colonisation of Eurasia and Oceania by 50,000 years ago. Both in Africa and Eurasia, Homo sapiens met with and interbred with[11][12] archaic humans. Separate archaic (non-sapiens) human species are thought to have survived until around 40,000 years ago (Neanderthal extinction), with possible late survival of hybrid species as late as 12,000 years ago (Red Deer Cave people).
The Latin noun homō (genitive hominis) means "human being" or "man" in the generic sense of "human being, mankind".[d] The binomial name Homo sapiens was coined by Carl Linnaeus (1758).[e][15] Names for other species of the genus were introduced beginning in the second half of the 19th century (H. neanderthalensis 1864, H. erectus 1892).
Even today, the genus Homo has not been strictly defined.[16][17][18] Since the early human fossil record began to slowly emerge from the earth, the boundaries and definitions of the genus Homo have been poorly defined and constantly in flux. Because there was no reason to think it would ever have any additional members, Carl Linnaeus did not even bother to define Homo when he first created it for humans in the 18th century. The discovery of Neanderthal brought the first addition.
The genus Homo was given its taxonomic name to suggest that its member species can be classified as human. And, over the decades of the 20th century, fossil finds of pre-human and early human species from late Miocene and early Pliocene times produced a rich mix for debating classifications. There is continuing debate on delineating Homo from Australopithecus—or, indeed, delineating Homo from Pan, as one body of scientists argues that the two species of chimpanzee should be classed with genus Homo rather than Pan.[citation needed] Even so, classifying the fossils of Homo coincides with evidence of: (1) competent human bipedalism in Homo habilis inherited from the earlier Australopithecus of more than four million years ago, as demonstrated by the Laetoli footprints; and (2) human tool culture having begun by 2.5 million years ago.[citation needed]