Out of Africa or Multiregional Theory Essay

For many years, scientists have wondered about the evolution of mankind. The two theories that scientists have come up with over the years to explain the theory of evolution were the multiregional theory and out of Africa theory. The multiregional theory expresses the idea that Homo erectus developed in different parts of the world. The out of Africa theory expresses that Homo erectus developed in Africa nearly two million-years-ago and as the temperatures changed, they moved throughout the world and developed differently. The multiregional view posits that genes from all human populations of the Old World flowed between different regions and by mixing together, contributed to what we see today as fully modern humans. The replacement hypothesis suggests that the genes in fully modern humans all came out of Africa. As these peoples migrated they replaced all other human populations with little or no interbreeding† (Johanson, 2001). The multi-regional hypothesis argues that our early hominid ancestors, including Homo ergaster and Homo heidelbergensis, migrated out of Africa and thus the evolution of modern humans took place in different parts of the world – a process termed regional continuity. This theory places great emphasis on the notion of steady evolutionary alterations or changes that happen in different regions and produce diverse variations of the species. Evolution of this kind is kept at a regular rate due to an amalgamation of cultural progress and ‘gene flow’ or interbreeding, thus keeping all lineages evolving at the same time. This process is characterized as parallel evolution, which suggests a subtle morphological resemblance between populations of species who are geographically separated† (Edwards, 2012). â€Å"The out of Africa view posits that Homo erectus migrated out of Africa the different populations became reproductively isolated, evolving independently, and in some cases like the Neanderthals, into separate species Homo sapiens arose in one place, probably Africa Homo sapiens ultimately migrated out of Africa and replaced all other human populations, without interbreeding modern human variation is a relatively recent phenomenon† (Johanson, 2001). The Out of Africa theory predicts that the earliest fossils of Homo sapiens will only be found in Africa along with any transitional fossils, marking the evolutionary process of these modern humans. Such fossils will not be found outside this area. Secondly, this model suggests that modern-day human populations may not necessarily share lineages or links with the earlier populations that inhabited the same region. This idea stems from the notion that the new populations of modern humans that inhabit an area will replace any archaic Homo species that occupy this region, thus establishing a new lineage of descent. Evidence in support of these ideas exists through multiple sources, showing the clear superiority of this theory in contrast with the multi-regionalist model. Such evidence can be found in the striking research of molecular geneticists; research which supports the idea of modern humans arising in one place and subsequently spreading elsewhere† (Edwards, 2012). Both theories were further examined through anatomical, archaeological, and genetic evidence to prove which theory seems more valid. â€Å"The anatomical and paleogeographic evidence suggests that Neanderthals and early modern humans had been isolated from one another and were evolving separately into two distinct species† (Johanson, 2001). â€Å"The genetic studies support the view that Neanderthals did not interbreed with Homo sapiens who migrated into Europe. It is, therefore, highly likely that modern humans do not carry Neanderthal genes in their DNA. † (Johanson, 2001). â€Å"Archaeological evidence from Europe suggests that Neanderthals may have survived in the Iberian Peninsula until perhaps as recently as 30,000 to 35,000 years ago. Fully modern humans first appear in Europe at around 35,000-40,000 years ago, bringing with them an Upper Paleolithic tool tradition referred to as the Aurignacian. Hence, Neanderthals and fully modern humans may have overlapped for as much as 10,000 years in Europe. Again, with fully modern humans on the scene, it is not necessary to have Neanderthals evolve into modern humans, further bolstering the view that humans replaced Neanderthals. † (Johanson, 2001). The out of Africa theory is the theory most scientists are approving as the evolution of all humans due to fossil, anatomical and genetic evidence. â€Å"Researchers have discovered fossilized remains of two previously unknown primate species that lived 37 million years ago in what is now the Egyptian desert. The ancient teeth and jawbones of the tiny, monkeylike creatures shed new light on the poorly understood evolution of early anthropoids, a suborder of primates that includes apes, monkeys, and humans. The discovery, researchers say, is evidence that the common ancestor of living anthropoids arose in Africa and that anthropoids have been evolving on the now separated Africa-Arabia landmass for at least 45 million years† (Lovgren, 2005). All evidence points to the out of Africa theory being the most probable theory.