“Apeman to Spaceman” –‘Changes in Earth’s Orbit and Climate Made Us Intelligent’




The wobbles and variations in the orbit of the Earth as it goes round the Sun have caused many periods of rapid and violent climate change. About two million years ago, something extraordinary started happening in the Great Rift Valley in East Africa. Our ape 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, from spears to spaceships.

Recent scientific evidence suggests that this evolutionary leap was driven by the impact of climate change on the Great Rift Valley (below) caused by the way that the Earth moves through space, as it orbits the Sun.




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. 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 below, 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 start answering 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.

Physicist Brian Cox examines how it was that in a universe made of stars, rocks and endless space, a conscious civilization was born in the BBC Human Universe video below. This adventure takes him from a submerged space station in Star City on the outskirts of Moscow, to Ethiopia, high above the great Rift Valley, where he encounters the geladas, mankind’s distant ancestors. Despite once being Africa’s most successful primate, a species who at one time roamed across the entire continent, these days they are found in just one place in the remote Ethiopian Highlands. Cox investigates why these ancestors retreated, yet modern mankind has expanded across the planet.



The Daily Galaxy via BBC and PLOS

Image credit: Ice Age humans left their footprints across what is now Willandra Lakes in southeastern Australia. With thanks to photographer Michael Amendolia/In Pictures/Corbis


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