What are the main theories for the origin of modern humans?
There are two main theories: the first is the multiregional hypothesis, which says that modern humans evolved generally at the same time in several regions, and gene flow between groups accounts for them not evolving into different species. The second, the Out of Africa or replacement hypothesis, says that modern humans evolved in Africa and then moved out to other parts of the world, replacing hominids that were already there. DNA studies support the Out of Africa hypothesis, and it is now more widely accepted.4 There is a hypothesis, the “weak Garden of Eden” model, which is a version of the Out of Africa theory. It suggests that humans dispersed from Africa about 100,000 years ago, suffered from a population bottleneck, and then recovered. The timing of Toba roughly matches the timing of the population bottleneck.4 Genetic evidence backs this up: since Africa, situated primarily on the equator, had the largest areas where humans could survive the volcanic winter, it retained a large
