LiveScience, 25 December 2012
At Olduvai Gorge, where excavations helped to confirm Africa was the cradle of humanity, scientists now find the landscape once fluctuated rapidly, likely guiding early human evolution.These findings suggest that key mental developments within the human lineage may have been linked with a highly variable environment, researchers added.
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The researchers discovered that Olduvai Gorge abruptly and routinely fluctuated between dry grasslands and damp forests about five or six times during a period of 200,000 years.
“I was surprised by the magnitude of changes and the rapid pace of the changes we found,” Freeman told LiveScience. “There was a complete restructuring of the ecosystem from grassland to forest and back again, at least based on how we interpret the data. I've worked on carbon isotopes my whole career, and I've never seen anything like this before.”