The Out-of-Africa Theory
|“We share a common ancestor -- a man who lived in Africa around 60,000 years ago. That's only about 2,000 generations... We're all effectively members of an extended family."|
|Spencer Wells, Genographic Project director|
In this Section, 1 we examine the Out-of-Africa 2 (“OoA”) answer to the question, “When and where did man become modern?” About 2 mya Homo erectus inhabited Africa, Europe, and Asia. In one of those locations he evolved into an archaic form of our species, Homo sapiens (Hs), then into modern man, Homo sapiens sapiens (Hss) and the people living today.
We will call the promoters of OoA, the dominant theory of our time, “afrocentrists.” They believe that it was the African erectus that evolved into Hs and that Hs evolved into Hss in Africa, then those modern African Hss migrated out of Africa “replacing” all the more primitive people who were then living in Europe (Neanderthals) and Asia (Homo erectus). Once those modern Africans moved into Eurasia, they lost all the African traits described in Section II and evolved all the Eurasian racial traits we see in today’s Asians and Europeans. That theory is consistent with egalitarianism because OoA holds that not very long ago all modern humans were Africans, so recently, in fact, that everyone is still virtually genetically the same, and therefore equal, particularly in behavior, intelligence, and the capacity for learning, but excepting “very superficial features like skin color and hair form.” 3 Genetic differences between populations are of no biological importance, however, only if they are neutral, i.e., they have no effect on the reproductive success of those populations. But, as Section II shows, genetic differences between races, including skin color and hair form, were the result of natural or sexual selection, which means that they did affect reproductive success. 4
The principal competing theory, the Multiregional theory, 5 is out of favor and is clung to by only a few die-hard scientists. And last, there is the theory presented in this book, which holds that Hs and Hss evolved in Eurasia (Out of Eurasia, “OoE”), not Africa. That theory will be presented in Section IV.
Figure III-1 is a tree that shows the OoA theory, where “LCA” is the last common ancestor of man (Homo) and chimpanzees (Pan).
Table of Contents
1. Most of the ideas and references in Section III came from Ronald A. Fonda and are described in (Fonda, 2001) and on his web site. Back
2. Aka, Recent African Origin (“RAO”), Recent Single Origin Hypothesis (“RSOH”), and Replacement Hypothesis. (Wikipedia, “Recent Single Origin Hypothesis”). Back
3. “It looks as though all non-African diversity is a product of the second migration of Homo sapiens out of Africa - a migration so recent that there just hasn't been time for the development of much genetic variation except that which regulates some very superficial features like skin color and hair form.” (“Race: The Power of an Illusion,” PBS television series, interview with Stephen Jay Gould, 2003). Back
4. An egalitarian can argue that modern civilization has made at least some of those differences neutral, but it is difficult to prove a negative (no effect) and some effects may be subtle and hard to detect. Back
5. The Multiregional Theory (aka “Regional Continuity”) holds that man evolved in Africa, left Africa about 2 mya for Eurasia and independently evolved on Africa, Australia, Asia, and Europe, with significant interbreeding. It is supported by Dr. Alan Thorne, a visiting fellow at the Australian National University's research school of Pacific and Asian studies, along with Professor Milford Wolpoff of the University of Michigan; also, Fred Smith and David Frayer in the U.S. and Wu Xinzhi in China. Also see (Coon, 1962) and (Weidenreich, 1947). “Unfortunately the implications of these rival theories have not been lost on either racists or anti-racists and there is a danger that the debate could become politicized.” (Haywood, 2000, p. 42). Back
6. Modern humans were living in India prior to the explosion of Mt. Toba, 73,000 ya. (Petraglia, 2007). Back
7. The same issue states that an earlier migration of modern humans made it to Israel, but died out about 90,000 ya. Back
8. However, a new study states, of the European-African split, “… we find a lower bound at 120,000 yrs and no upper bound.” (Plagnol, 2006). Others believe there were at least two major population expansions out of Africa; one about 600,000 ya and another about 95,000 ya (Cann, 2002) and that a much earlier expansion of Homo erectus from Africa occurred 1.7 mya. (Templeton, 2002). Back