Ed Yong writes:

There is a decades-old origin story for our species, in which we descended from a group of hominids who lived somewhere in Africa around 200,000 years ago. Some scientists have placed that origin in East Africa; others championed a southern birthplace. In either case, the narrative always begins in one spot. Those ancestral hominids, probably Homo heidelbergensis, slowly accumulated the characteristic features of our species—the rounded skull, small face, prominent chin, advanced tools, and sophisticated culture. From that early cradle, we then spread throughout Africa, and eventually the world.

But some scientists are now arguing that this textbook narrative is wrong in its simplicity, linearity, and geography. Yes, we evolved from ancestral hominids in Africa, but we did it in a complicated fashion—one that involves the entire continent.

Consider the ancient human fossils from a Moroccan cave called Jebel Irhoud, which were described just last year. These 315,000-year-old bones are the oldest known fossils of Homo sapiens. They not only pushed back the proposed dawn of our species, but they added northwest Africa to the list of possible origin sites. They also had an odd combination of features, combining the flat faces of modern humans with the elongated skulls of ancient species like Homo erectus. From the front, they could have passed for us; from the side, they would have stood out.

Fossils from all over Africa have modern and ancient traits in varied combinations, including the 260,000-year-old Florisbad skull from South Africa; the 195,000-year-old remains from Omo Kibish in Ethiopia; and the 160,000-year-old Herto skull, also from Ethiopia. Some scientists have argued that these remains represent different subspecies of Homo sapiens, or different species altogether.

But perhaps they really were all Homo sapiens, and our species simply used to be far more diverse than we currently are. “If you look at skulls, you’ll see different features of modern humans arising in different locations at different times,” says Eleanor Scerri, an archaeologist at the University of Oxford. And the reason for that, she says, is that “we’re a species with multiple African origins.” [Continue reading…]