Study: Human evolution has sped up enormously in the past few thousand years, making us more different from people who lived in 3,000 BCE than they were from Neaderthals. Why? The stunning rate of population growth in that period has enabled an enormous number of mutations. Natural selection is way more interesting when there’s so much more to select from. The result is that genes that didn’t exist 5,000 years ago are now found in 40% of the human population. Wow!