How environmental changes may have helped make ancient humans more adaptable
A sediment core traces 1 million years of ecological shifts in eastern Africa
By Bruce Bower
An unforgiving environmental twist deserves at least some credit for the behavioral flexibility that has characterized the human species since our African origins around 300,000 years ago, a new study suggests.
For hundreds of thousands of years in parts of East Africa, food and water supplies remained fairly stable. But new evidence shows that starting about 400,000 years ago, hominids and other ancient animals in the region faced a harsh environmental reckoning, says a team led by paleoanthropologist Rick Potts of the Smithsonian Institution in Washington, D.C.
The climate began to fluctuate dramatically. Faults caused by volcanic eruptions fractured the landscape and reduced the size of lakes. Large animals died out and were replaced by smaller creatures with more diverse diets. These changes heralded a series of booms and busts in the resources hominids needed to survive, Potts and his colleagues report October 21 in Science Advances.
Around that time, hominids at a site called Olorgesailie in what’s now Kenya transformed their culture. That shift, between around 500,000 and 320,000 years ago, was probably influenced by increasingly unpredictable periods of water and food scarcity, the scientists contend.