The argument advanced in favour of the regional continuity model of human origins is that archaic Homo sapiens evolved at different rates in different regions into modern humans. That’s why there was difference in the first appearance of modern humans in various parts of world. This argument is based on the regional differences in the characteristics of present day humans. According to the supporters of this argument, these dissimilarities are because of the difference between the pre-existing Homo heidelbergensis and Homo erectus populations which lived in the same region.