Biology 1001A Chapter Notes - Chapter chapter 22: Species, Neanderthal, Denisovan
19 Dec 2017
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Document Summary
Competing theories about where modern humans (homo sapiens) evolved, and which is best supported by available evidence. African emergence hypothesis proposes that early hominin descendants (archaic humans) left africa and established populations in the middle east, asia, and. Some time later, 100 thousand to 200 thousand years ago, h. sapiens arose in africa and also migrated into europe and asia. Perhaps through competition, h. sapiens eventually drove archaic humans to extinction. This hypothesis suggests that all modern humans are descended from a fairly recent african ancestor. Multiregional hypothesis suggests that populations of h. erectus and archaic humans had spread through much of europe and asia by 500 thousand years ago and modern humans (h. sapiens) evolved from descendants of these earlier dispersals. Although these geographically separated populations may have experienced some evolutionary differentiation, gene flow between them prevented reproductive isolation and maintained them as a single but variable species, h. sapiens.
