From New Scientist:
The ways in which climate affected human evolution have been hotly debated for over a century. A persistent idea is that the challenging climate of southern Africa – a sparsely vegetated, dry savannah – drove humans to walk on two legs, grow large brains and develop technology. “I was hooked on the savannah-adaptation idea in my studies in the 1980s,” says Rick Potts from the Smithsonian Institute in Washington DC (see diagram).
But by the 1990s, Potts had a new theory. “I realised that the critical part of the human evolutionary story is how our lineage was able to become so versatile… capable of invading habitats everywhere,” he says. We’re not master savannah inhabitants, we’re master invaders. This led Potts to suggest that maybe it was environmental change itself – not a particular environment – that drove human evolution. “A rise in variability of climate places a premium on being nimble, versatile, to ensure survival,” he says. More.
Hmmm. Climate change would necessarily help shape all kinds of evolution. One either adapts or goes extinct. While Potts’ theory is interesting, it doesn’t shed much light on why only humans became big-brained and bipedal in response to it.
See also: What we think we know about human evolution
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