Energetics and the Ecology of Early Homo

Life takes energy: essential tasks like growth, maintenance, reproduction, and movement all require metabolic energy expenditure. Compared to our closest relatives, the great apes, humans have larger brains, faster reproduction, greater physical activity levels, and longer lifespans, indicating major evolutionary changes in the ways our bodies expend energy. In this talk, I investigate humans’ evolving metabolic strategy and its origins in the fossil record.  Comparisons with living apes show that humans burn more calories each day, providing the energy needed to fuel our larger brains and faster reproduction. Humans also exhibit adaptations to expend energy more efficiently, particularly during walking, and to store more energy as fat. Fossil and archeological evidence suggests these critical adaptations develop with the origin of the genus Homo. These findings help illuminate the ecological pressures shaping our genus and the evolutionary origins of obesity and metabolic disease.