Alternative theories of the origin of human diversity

The so-called "Candelabra Theory" of regional continuity (left) suggests that diversity among extant human populations arose originally from within Homo erectus and has continued over several million years, with some exchange of genes (arrows). The "single origin" theory suggests that all extant populations stem from a relatively recent, probably African, population. Molecular evidence strongly favors the latter theory, with a common ancestor of all living humans at ~250,000 YBP  [Illustration from Scientific American; see 07 Dec 2000 "Nature" article].

Text material © 2005 by Steven M. Carr