Following the appearance of the neocortex some 250,000 years in our past, Homo sapiens evolved as the only species on planet Earth that created sophisticated technology from the clock to the radio and the quantum computer. In Apeman to Spaceman, the BBC reported that about two million years ago, something extraordinary started happening in the Great Rift Valley in East Africa that led our Anthropocene epoch. Our simian ancestors began to evolve from animals with brain power close to that of a chimpanzee, to apes that would ultimately become human – able to talk, and construct complex tools.
Scientists suggest this evolutionary leap may be the response to rapid and violent climate change triggered by the wobbles and variations in the orbit of the Earth.
That may only have happened because gravity of the Sun, Moon, and other planets in our Solar System makes the Earth’s orbit change how elliptical it is, over thousands of years, which in turn affects our planet’s climate. Our early ancestors’ increases in brain size occurred when the Earth’s orbit was at its most elliptical, a time of rapid and violent climate change, when adaptability and intelligence would have been a huge evolutionary advantage.
A few large evolutionary leaps, such as bigger brains and complex tool use, seem to coincide with significant climate change. “I think, to be fair, all we have at the moment is coincidence,” said paleoclimatologist Peter B. deMenocal of Columbia University’s Lamont-Doherty Earth Observatory and founding director of Columbia’s Center for Climate and Life. But he and other researchers are exploring several lines of evidence, from ancient teeth to seafloor sediments, to see if a more concrete link can be supported.
In the video above, DeMenocal speaks about how climate change might have driven turning points in human evolution. The rise of genus Homo and stone tools coincides with green periods in climate change two million years ago in East Africa. It’s too early to tell for sure, said deMenocal, but scientists have the ability today to probe whether this link is solid.
The theory that climate change drove the evolution of human intelligence is based on the latest evidence of how the landscape changed in the Great Rift Valley over hundreds of thousands of years. Apes with bigger brains were able to construct more advanced tools and weapons, giving them an advantage when hunting, or butchering meat. This could have created an evolutionary pressure for brains to get larger, which could have helped our ancestors form more complex social groups that were able to co-operate when times got tough.
The Daily Galaxy, Andy Johnson, via BBC and Scientific American, New Evidence Shows How Human Evolution Was Shaped by Climate
Image credit: Google Earth. Data SIO, NOAA, US Navy, NGA, GEBCO