What Doesn't Kill Us: How Freezing Water, Extreme Altitude, and Environmental Conditioning Will Renew Our Lost Evolutionary Strength

by Scott Carney

Homo erectus was different than the great apes that preceded it. Homo erectus walked upright on two feet, and, because digestion takes less time when food is cooked, has a smaller gut than most apes. Over the next million years or so Homo erectus experienced a gentle progression into the more refined human form we now enjoy. Presumably because Homo erectus didn’t have to spend so much time chewing, it could do other things that led to evolutionary pressure that increased reliance on technical skill; therefore, brain size increased. At some point, Homo erectus also lost its body hair, seemingly because he could use fire to keep himself warm at night.