The current scientific view of human origins and genetic variation holds that all humans belong to a single species. Revolutionary genetic research tools have revealed that human genetic diversity is low relative to other species, that human populations have only recently diverged from one other, and that the small degree of genetic differentiation among living human populations is linked primarily to adaptations to differing environments. Maryellen Ruvolo will discuss how this consensus on human evolutionary biology contrasts sharply with beliefs held in the previous century.