The place of origin of the humans or modern man is a much-debated issue. There are two divergent theories. 

1. The Replacement or African origin Theory. 

2. The Regional Continuity theory.

The Replacement (or) African origin theory: According to this theory, modern human species evolved from the archaic species in Africa. Africa with its nurturing tropical climate consisting of strong wet and dry seasons provided an optimum environment for the emergence of the modern human species. Some of them migrated to different regions of the world at different points of time. They replaced the earlier human-like species in these regions.

The discovery of fossils of the early human species in Africa and the genetic and anatomical homogeneity among the modern humans in all parts of the world are evidence for this theory. The Regional continuity theory: According to this theory, the evolution of different human species from the earlier species occurred in all regions of the world. It occurred in Europe and Asia also as it occurred in Africa. The evolution proceeded at different rates in different regions. The dissimilarities among the human populations in different regions of the world, serve as evidence to this theory.