Environmental and Behavioral Evidence Pertaining to the Evolution of Early Homo

East African paleoenvironmental data increasingly inform an understanding of environmental dynamics. This understanding focuses less on habitat reconstructions at specific sites than on the regional trends, tempo, and amplitudes of climate and habitat change. Sole reliance on any one indicator, such as windblown dust or lake sediments, gives a bias toward strong aridity or high moisture as the driving force behind early human evolution. A synthesis of geological data instead offers a new paleoenvironmental framework in which alternating intervals of high and low climate variability provided the dynamic context in which East African Homo evolved. The Oldowan behavioral record presents further clues about how early Homo and Homo erectus responded to East African environmental change. Shifting conditions of natural selection, which were triggered by climatic variability, helped shape the adaptability of Oldowan hominins. Together, the behavioral and environmental evidence indicates the initial adaptive foundation for the dispersal of H. erectus and the persistence of Homo. In particular, overall dietary expansion made possible by the making and transport of stone tools compensated for increased locomotor and foraging costs and provided effective behavioral-ecological responses to resource instability during the early evolution of Homo.