The Replacement Hypothesis

The ‘replacement hypothesis’ is sometimes called the ‘out-of-Africa’ hypothesis as well.  This hypothesis claims that after archaic sapiens spread from Africa to Asia and Europe, modern sapiens evolved from archaic sapiens in Africa, and then spread throughout the world.  Following this so-called ‘second expansion’, the modern sapiens replaced the archaic sapiens without interbreeding with them to any appreciable extent.

 So, the modern sapiens that evolved from archaic sapiens in Africa were reproductively isolated from Eurasian populations of archaic sapiens.  According to this hypothesis, the archaic sapiens would have become extinct due to competition.  Therefore, most genes in today’s populations would be descended from those carried by the population of modern sapiens that spread from Africa.

Here is a map of various hominid fossil localities around the globe.