Brain size and thermoregulation during the evolution of the genus Homo.

摘要: Several hypotheses have been proposed to explain the evolution of an energetically costly brain in genus Homo. Some these are based on correlation between climatic factors and size recorded for this during last millions years. In study, we propose a complementary hypothesis that is mechanistic connection temperature, thermoregulation, internal organs endothermic species. We hypothesized global cooling 3.2 my may imposed increased energy expenditure which case hominids could represent driver expanded brain, or at least, it imply relaxation negative selection pressure acting upon organ. To test idea, here (1) assess variation energetic costs thermoregulation maintenance my, (2) evaluate relationship Earth temperature cost same period, taking into account effects body mass fossil age. found that: associated with enlargement represents important fraction (between 47.5% 82.5%) increase needed thermoregulation; age better predictor than suggesting (at least) another factor correlated time was more relevant ambient evolution; (3) there significant even after accounting effect Thus, our results expand current framework study lineage by fall years facilitated enlargement.