Homo Adapts to Diverse Environments, Says Fossil Data & Earth Model

Homo species – particularly Homo sapiens­ – were uniquely equipped to adapt to highly diverse environmental conditions and landscape mosaics, according to a new study, which may have enabled our species and that of our closely related ancestors to survive and thrive in highly fluctuating Pleistocene environments. Homo sapiens are the only surviving hominin species today. However, whether this is because our species was uniquely successful at adapting to Pleistocene environments, because we outcompeted other contemporary Homo species through unique physiological or social adaptations, or because we simply outlived others by chance remains largely unknown. Although challenging to understand, the connection between hominins and their ecological environment, particularly how Homo species adapted to environmental change and extremes and how this affected survival and migration from Africa and into Eurasia, is central to findings these answers. Combining a transient 3-million-year Earth system-biome model simulation (BIOME4) with archaeological and fossil data for 6 different Homo species, Elke Zeller and colleagues investigated the preferred environmental conditions of the different hominin species, whether biome preferences changes in time or diversity across the Pleistocene, and how these choices affected hominin adaptation. Zeller et al.'s analysis shows that early African hominins, including H. habilis and H. ergaster, predominantly lived in open and dry grassland environments. H. erectus, upon leaving the African continent, settled in a much more broad suite of environments, including temperate forested regions. This trend continued for more recent species, like H. erectus and H. neanderthalensis, who were able to adapt to colder habitats. According to the findings, H. sapiens were able to occupy the most extreme environments, such as deserts and tundra, an ability that suggests the development of unparalleled cognitive abilities, allowing them to exploit habitat diversity and diverse food resources. Overall, the study reveals a pattern of Homo species preferentially selecting and adapting to areas with more diverse habitats over the last 3 million years.