Human evolution

Human evolution is the process of change and development, or evolution, by which human beings emerged as distinct species. It is the subject of a broad scientific inquiry that seeks to understand and describe how change and development took place. The study of human evolution encompasses many scientific disciplines, but most notably physical anthropology and genetics. The term "human", in the context of human evolution, refers to the genus Homo, but studies of human evolution usually include other hominids, such as the australopithecines.

The Homo genus

In modern taxonomy, Homo sapiens is the only extant species of its genus, Homo. Likewise, the ongoing study of the origins of Homo sapiens often demonstrates that there were other Homo species, all of which are now extinct. While some of these other species might have been ancestors of H. sapiens, many were likely our "cousins", having speciated away from our ancestral line. There is not yet consensus as to which of these groups should count as separate species and which as subspecies of another species. In some cases this is due to the paucity of fossils, in others due to the very slight differences used to distinguish species in the Homo genus.

Related Topics:
Species - Homo

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The word homo is simply the Latin for "person", chosen originally by Carolus Linnaeus in his classificatory system. It is often translated as "man", although this can lead to confusion, given that the English word "man" can be generic like homo, but can also specifically refer to males. Latin for "man" in the gender-specific sense is vir, cognate with "virile" and "werewolf". The word "human" is from humanus, the adjectival form of homo.

Related Topics:
Latin - Carolus Linnaeus - Cognate

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H. habilis

Lived from about 2.4 to 1.5 million years ago (MYA). H. habilis, the first species of the genus Homo, evolved in South and East Africa in the late Pliocene or early Pleistocene, 2.5–2 MYA, when it diverged from the Australopithecines. H. habilis had smaller molars and larger brains than the Australopithecines, and made tools from stone and perhaps animal bones.

Related Topics:
H. habilis - Africa - Pliocene - Pleistocene - Australopithecines - Molars - Brain - Tools - Stone - Bones

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Homo erectus

Lived from about 1.8 (including ergaster) or from about 1.25 (excluding ergaster) to 0.07 MYA. In the Early Pleistocene, 1.5–1 MYA, in Africa, Asia, and Europe, presumably Homo habilis evolved larger brains and made more elaborate stone tools; these differences and others are sufficient for anthropologists to classify them as a new species, H. erectus. A famous example of Homo erectus is Peking Man; others were found in Asia (notably in Indonesia), Africa, and Europe. Many paleoanthropologists are now using the term Homo ergaster for the non-Asian forms of this group, and reserving H. erectus only for those fossils found in the Asian region and meeting certain skeletal and dental requirements which differ slightly from ergaster.

Related Topics:
Ergaster - Asia - Europe - Homo habilis - H. erectus - Peking Man

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H. ergaster

Lived from about 1.8 to about 1.25 MYA. Also proposed as Homo erectus ergaster

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Homo heidelbergensis

(Heidelberg Man) lived from about 800 thousand years ago (TYA) to about 300 TYA. Also proposed as Homo sapiens heidelbergensis and Homo sapiens paleohungaricus.

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Homo sapiens idaltu

Lived from about 160 TYA (proposed subspecies). Is the oldest anatomically modern human known.

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Homo floresiensis

From about 12 TYA (announced 28 October 2004 in the science journal Nature)). Nicknamed hobbit for its small size.

Related Topics:
October - 2004 - Nature) - Hobbit

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H. neanderthalensis

Lived from about 250 to 30 TYA. Also proposed as Homo sapiens neanderthalensis. There is ongoing debate over whether the "Neanderthal Man" was a separate species, Homo neanderthalensis, or a subspecies of H. sapiens. While the debate remains unsettled, the preponderance of evidence, collected by examining mitochondrial DNA and Y-chromosomal DNA, currently indicates that there was no gene flow between H. neanderthalensis and H. sapiens, and therefore the two were separate species. In 1997 Dr. Mark Stoneking, then an associate professor of anthropology at Penn State University, stated: "These results indicate that Neanderthals did not contribute mitochondrial DNA to modern humans… Neanderthals are not our ancestors."² Subsequent investigation of a second source of Neanderthal DNA confirmed these findings.³

Related Topics:
Neanderthal Man - Mitochondrial DNA - Y-chromosomal - DNA - 1997

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H. sapiens

Lived from about 200 TYA to the present. Between 400,000 years ago and the second interglacial period in the Middle Pleistocene, around 250,000 years ago, the trend in cranial expansion and the elaboration of stone tool technologies developed, providing evidence for a transition from H. erectus to H. sapiens. The direct evidence suggests that there was a migration of H. erectus out of Africa, then a further speciation of H. sapiens from H. erectus in Africa. (There is little evidence that this speciation occurred elsewhere.) Then a subsequent migration within and out of Africa eventually replaced the earlier dispersed H. erectus. However, the current evidence doesn't preclude multiregional speciation, either. This is a hotly debated area in paleoanthropology. "Sapiens" means "wise" or "intelligent."

Related Topics:
Pleistocene - H. sapiens - Migration - Subsequent migration - Paleoanthropology

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