Origin of Homo sapiens

Origin of Homo sapiens - more elaborate brain to control...

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Origin of Homo sapiens: Australopithecus afarensis = first bipedal hominid, found in east Africa about 3.0-3.2 MYBP. Later forms became more slender (= "gracile"). Homo habilis and H. erectus (~1.5mybp) came later. The evolution of bipedalism may have freed the hands for us in other functions: carrying, tool use. The trends in the evolution of tool use (more types, more specific tasks, different types of materials, more efficient use of materials) seems to follow (lead??) the evolution of increase cranial capacity . These both seem to increase noticeably about 2 mybp. One theme that involves each of the different sequences of evolution is that there was some feedback that lead to the increase in cranial capacity, e.g., becoming bipedal creates selection pressure for a
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Unformatted text preview: more elaborate brain to control motor function and to process incoming sensory information. This in turn would allow for more successful bipedalism, etc. The same argument could be leveled about culture leading to an increase in brain size, and vice versa, so the sequence cannot be resolved just on the logic of feedback loops alone. Origin of " modern humans": Two alternative scenarios for origins: 1) humans originated in more than one site ("Multiregional" model). Evidence supporting this are modern Homo sapiens samples found in Asia and Africa 2) a single origin ("Noah's Ark" model: one origin and dispersal out from site of origin). Homo sapiens are believed to have originated ~100,000 - 200,000 years ago....
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