ch 5: This chapter examines African evidence for human origins, behavior, and population movements between 50 and 600 Ka (thousands of years ago). It compares evidence associated with Homo sapiens and H. heidelbergensis. Homo sapiens and H. heidelbergensis solved survival challenges in broadly similar ways, with humans occasionally devoting more time and energy to technology (“technological intensification”). The African evidence is entirely consistent with dispersal, showing not even a hint of migration. This and other evidence suggest humans replaced earlier H. heidelbergensis not by an abrupt evolutionary event originating in one place and radiating outward but instead by a gradual, continent-wide process whose mode and tempo varied widely.