Our species separated into two parts 50, 60, or 70 thousand years ago, depending on which paleoanthropologist you ask. One part remained in Africa, the ancestral homeland. The other crossed into Southwest Asia, then split, and re-split, and re-split, until there were human populations living in near-total reproductive isolation from each other in all parts of the world. This went on for hundreds of generations, causing the divergences we see today. Different physical types, as well as differences in behavior, intelligence, and personality, are exactly what one would expect to observe when scrutinizing these divergent populations.
We see the same differences in traits that we don’t think of as directly physical, what evolutionary psychologists sometimes refer to as the “BIP” traits — behavior, intelligence, and personality. Two of the hardest-to-ignore manifestations here are the extraordinary differentials in criminality between white Americans and African Americans, and the persistent gaps in scores when tests of cognitive ability are given to large population samples.
Via United States of Jamerica.