Friday, July 23, 2010

Human behavioral adaptations accelerating evolutionary changes

What I'm saying is either 1. so obvious noone's bothered to say it, 2. wrong, or 3. somewhat interesting. It's about the evidence of a significant recent natural selection in the human genome, covered in the New York Times.

Our behavioral adaptations have made it possible for our primate body to succeed in new habitats and climates. After the successful introduction into new niches, we started competing against the most dangerous game, each other, and evolution started playing catch-up, adapting our bodies to colder climates, less sunlight, and higher elevations as applicable.

Then instead of just entering new habitats as hunter-gatherers spread around the world, humans also started creating new habitats through agriculture, succeeded there and began competing on evolutionary levels, like when Asians adapted to metabolize alcohol after inventing rice cultivation. In the last few thousand years or less, we created still more new habitats of dense populations in cities, and resistance to diseases that spread at high concentrations like measles began to develop.

I think it's interesting because evolution is working on us in ways or at a speed that's highly unusual, because a species usually succeeds in a particular type of habitat instead of spreading to multiple habitats simultaneously.

I suppose it's similar to adaptive radiation, like where an ancestral finch species reached the Galapagos and eventually became 14 species adapted to different food sources. I just suspect it's happened much faster with us. And of course we won't differentiate into separate species, given the high level of gene flow.

It might be interesting to look at species that have come along for the ride with us - rats, house mice, cockroaches, head lice, gut bacteria - and see if they've undergone similar recent evolution.


  1. Great post, looking at evolution is always interesting, coming up with new theories is part of the fun.

  2. Anonymous8:30 PM

    do you honestly think we evolved that humans came about by chance? if scientists cant even comprehend the complexity of our brains, do u think its all random adaptation? chance or was it created?


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