The impact of past climate changes on human evolution

The genus Homo evolved during the Pleistocene – an epoch of gradual cooling and strengthening of glacial cycles. The changing climate affected early human survival, adaptation and evolution in complex ways. In this review, we present current knowledge about the effects of past climate change on the evolutionary trajectory of the human species. Humans appeared in dry grasslands and bushes when the average climatic conditions were warm. As the global climate began to cool, human species needed to either follow their preferred habitats or adapt to new local conditions, each of which is reflected in the archaeological record. Limited dispersal ability and narrow ecological preferences predominated in early species, while cultural innovations and consequently wider ecological niches became common in later species, allowing them to live in cooler extratropical climates. However, despite their increasing ecological versatility, all but one species eventually became extinct. Future research should examine cultural transmission between and within species and the impact of climate change on human genetic diversification. ( Axel Timmermann, Pasquale Raia, Kyung-Sook Yun, more at nature.com)