Compare and contrast the out-of-Africa model and multiregional theories of the origin of modern man. Which theory
is supported by the preponderance of genetic evidence? What type of evidence supports the other theory What will be an ideal response?
The multiregional model: Originally, there were two opposing views on how and where our
species originated. One school of thought used fossil evidence to argue that after leaving
Africa, members of the genus Homo formed a network of interbreeding populations that
gradually transformed into our species, H. sapiens. This model favors evolution and
transition within the genus Homo.
The out-of-Africa model: The other school of thought used a combination of genetic and
fossil evidence to argue that our species originated in Africa between 200,000 and 100,000
years ago. The genetic evidence shows that small groups of H. sapiens spread from Africa by
about 60,000 years ago and replaced earlier populations of other human species, including H.
erectus and Neanderthals (H. neanderthalensis), and perhaps H. floresiensis, driving them
into extinction. This model favors speciation in Africa, followed by migration and
replacement of other species.
The evidence now overwhelmingly supports the out-of-Africa model, identifying
southwestern Africa as the most likely place where modern humans originated and East
Africa as the point of migration from Africa. According to this model, modern human
populations are all derived from a single speciation event that took place in a restricted region
within Africa. As a result, the human populations who remained in Africa have the highest
degree of genetic diversity, and all populations outside Africa show a high degree of genetic
relatedness because they are derived from the relatively small migrant population.
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