Human origins are notoriously tough to pin down. Fossil and genetic studies in 2017 suggested a reason why: No clear starting time or location ever existed for our species.
Homo sapiens’ signature skeletal features emerged piece by piece in different African communities starting around 300,000 years ago, researchers proposed. In this scenario, high, rounded braincases, chins, small teeth and faces, and other hallmarks of human anatomy eventually appeared as an integrated package 200,000 to 100,000 years ago.
This picture of gradual change contrasts with what scientists have often presumed, that H. sapiens emerged relatively quickly during the latter time period.
“Speciation is a process, not an event,” says paleoanthropologist Bernard Wood of George Washington University in Washington, D.C. “When fossil skulls of, say, Neandertals and Homo sapiens look convincingly different, we’re seeing the end of the speciation process.”
Previous genetic comparisons of present-day humans with Neandertals and their close Stone Age relatives, the Denisovans, had placed human origins at 400,000 years ago or more. Many investigators found that estimate difficult to reconcile with a human anatomy that appears to gel much later.
Studies of DNA from living Africans, and from the 2,000-year-old African boy, so far indicate that at least several branches of Homo— some not yet identified by fossils — existed in Africa roughly 300,000 years ago, says paleoanthropologist John Hawks of the University of Wisconsin–Madison.
Read full, original post: The story of humans’ origins got a revision in 2017