Overview
The term "multiregional hypothesis" was coined in the early 1980s by Milford H. Wolpoff and colleagues, who used the theory to explain regional similarities between archaic humans and modern humans in various regions, in what they called regional continuity. Wolpoff proposed that the mechanism of clinal variation allowed for the necessary balance between both local selection and overall evolution as a global species, with Homo erectus, Neanderthals, Homo sapiens and other human forms as subspecies. This species arose in Africa two million years ago as H. erectus and then spread out over the world, developing adaptations to regional conditions. Some populations became isolated for periods of time, developing in different directions, but through continuous interbreeding, replacement, genetic drift and selection, adaptations that were an advantage anywhere on earth would spread, keeping the development of the species in the same overall direction while maintaining adaptations to regional factors. By these mechanisms, surviving local varieties of the species evolved into modern humans, retaining some regional adaptations but with many features common to all regions.
Read more about this topic: Multiregional Origin Of Modern Humans