Tuesday, January 14, 2020

How Humans Came to the Americas

From The Smithsonian:
Now our understanding of when people reached the Americas—and where they came from—is expanding dramatically. The emerging picture suggests that humans may have arrived in North America at least 20,000 years ago—some 5,000 years earlier than has been commonly believed. And new research raises the possibility of an intermediate settlement of hundreds or thousands of people who spread out over the wild lands stretching between North America and Asia.

The heart of that territory has long since been submerged by the Pacific Ocean, forming the present-day Bering Strait. But some 25,000 to 15,000 years ago, the strait itself and a continent-size expanse flanking it were high and dry. That vanished world is called Beringia, and the developing theory about its pivotal role in the populating of North America is known as the Beringian Standstill hypothesis—“standstill” because generations of people migrating from the East might have settled there before moving on to North America.

Much of this new theorizing is driven not by archaeologists wielding shovels but by evolutionary geneticists taking DNA samples from some of the oldest human remains in the Americas, and from even older ones in Asia. Those discoveries have opened a wide gap between what the genetics seem to be saying and what the archaeology actually shows. Humans may have been on both sides of the Bering Land Bridge some 20,000 years ago. But skeptical archaeologists say they will not believe in this grand idea until they hold the relevant artifacts in their hands, pointing out that no confirmed North American archaeological sites older than 15,000 to 16,000 years currently exist. But other archaeologists are confident it is only a matter of time until older sites are discovered in the sprawling, sparsely populated lands of eastern Siberia, Alaska and northwestern Canada. (Read more.)

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