Distinguish between the replacement and regional …

There have been two prevalent, contrasting theories as to how humans came up in various regions on Earth.
One of them is the Regional Continuity Model, which emphasizes that the archaic Homo sapiens in different regions gradually evolved at different rates into modern human beings, and hence there were variations in the appearance of the first human beings on different parts of the world.
This argument is based on the regional differences in the features of present-day humans.
The other is the Replacement Model, which visualizes the complete replacement of all older forms of humans with modern humans.
This view is supported by the evidence of the genetic and anatomic homogeniety amongst all modern humans. Historians who support this view argue that the enormous similarity is due to the common descent from a population that originated in a single region, which is Africa