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2018-07-11. Our ancestors may have left Africa hundreds of thousands of years earlier than thought.

posted Jul 14, 2018, 8:59 AM by Alan Gould
By Ann Gibbons, Science Magazine. For GSS Life and Climate chapter 11. Excerpt: More than 2 million years ago, our ancestors were already world travelers, trekking all the way from Africa to Asia, according to stone tools found on a cliff face in north-central China. The age of the tools suggests that the forebears of modern humans left Africa at least 250,000 years earlier than thought; it also supports a minority view that a key human ancestor, Homo erectus, may have originated in Asia, not in Africa. Until now, the oldest evidence of human ancestors outside of Africa was in Dmanisi, Georgia. Here, fossils of short people thought to be early H. erectus date back to about 1.85 million years—just after the species appears in Africa. The oldest evidence of early human activity in China and Indonesia has been fossils and stone tools that date to 1.5 million to 1.7 million years ago.... Now, evidence from the site of Shangchen, ...is shaking up that view. On the steep cliff faces of a gully at Shangchen, a Chinese team unearthed 96 stone points, flakes, and cores that were probably used to carve up animal bones or to smash them open for marrow. ...led by geologist Zhaoyu Zhu of the Guangzhou Institute of Geochemistry...the researchers used paleomagnetic dating—which detects known reversals in Earth’s magnetic field that are recorded in ancient rock—and found that the stone tools range in age from 1.6 million to 2.1 million years ago. This indicates hominins—the family that includes humans and our ancestors—got out of Africa at least a quarter of a million years earlier than thought, and occupied Shangchen on and off for more than 850,000 years, the team reports today in Nature.... http://www.sciencemag.org/news/2018/07/our-ancestors-may-have-left-africa-hundreds-thousands-years-earlier-thought
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