Humans Adapted to Diverse Habitats as Climate and Landscapes Changed

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https://eos.org/articles/humans-adapted-to-diverse-habitats-as-climate-and-landscapes-changed

By Deepa Padmanaban, Eos/AGU. 

Excerpt: Our genus, Homo, evolved over 3 million years by adapting to increasingly diverse environments. Now, a new study published in Science deeply explores how six species of Homo(H. ergaster, H. habilis, H. erectus, H. heidelbergensis, H. neanderthalensis, and early H. sapiens) adapted to habitats across Africa and Eurasia. In its analysis, the team of scientists from South Korea and Italy used data from more than 3,000 human fossil specimens and archaeological sites. They then combined those data with climate and vegetation models of the past 3 million years. ...during the early to middle Pleistocene (about 2.6 million years ago to 0.5 million years ago), massive changes in Earth’s climate played a role in the distribution of vegetation, as well as the evolutionary development of the Homo species studied. ...the climate has cooled considerably over the past 3 million years. Reasons for this pattern of climate change include a gradual decrease in atmospheric carbon dioxide levels, glacial cycles brought on by long-term changes in Earth’s orbit and axis, and, after the Mid-Pleistocene Transition (MPT) about 1 million years ago, a lengthening of glacial cycles from about 41,000 years to about 100,000 years. ...“Because cold air holds less water, planetary cooling was accompanied by an overall drying.” This global cooling resulted in a shrinking of warm tropical forests in central Africa and southern Europe—habitats to which the early hominins H. ergaster and H. habilis were adapted. Forests were replaced by more open environments such as grassland and dry shrubland....

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