Figure Caption: Anatomically modern humans (AMH) and archaic forms of Homo in shape space. Two-dimensional projection of the first 3 principal components of the neurocranial shape coordinates and one example (from Mladec 1) for the full set of landmarks and semi-landmarks measured on each neurocranium. Recent humans in light brown; UP fossils in blue; early AMH in red; Neanderthals in green, archaic Homo in orange.
The isolation by distance theory argues that anatomically modern humans evolved in Africa at least by 195,000 years ago (Omo Kibish) and then expanded throughout Africa. Some groups in Africa became isolated, and some died out or were colonized by other groups. Different groups left Africa at different times perhaps beginning about 100,000 years ago (Skhul Cave, Israel), and some perhaps returning to Africa later, leading to the diversity of human beings on the planet today.
Evidence underpinning this theory was collected by researchers at the University of Vienna and the Max Planck Institute, who compared skull forms of archaic homo, Neanderthal and early anatomically modern humans and revealed that although those three populations were separate, early modern humans were the most diverse and although the groups overlap, they also group loosely into geographic regions: Africa, Asia, Australia and Europe.
Researchers believe that this variation and theme among early modern humans resulted from an isolation of different groups within Africa, and then again after the different groups left Africa.
Theories of Human Population
Gunz, Philipp, et al. 2009 Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario. Proceedings of the National Academy of Sciences Early Edition.
