Slashdot linked up this NYTimes article detailing a new discovery in human evolution:

Providing the strongest evidence yet that humans are still evolving, researchers have detected some 700 regions of the human genome where genes appear to have been reshaped by natural selection, a principal force of evolution, within the last 5,000 to 15,000 years.

While new to these researchers and the NYT, we were discussing such adaptations in my physical anthropology undergrad classes back in the late '80s. The funnest one to talk about, which is not actually discussed in the article, is tooth evolution.

Our meat-and-berry eating ancestors actually started to lose a whole unneeded tooth, which is why wisdom teeth come in irregularly and sometimes not at all. However agriculture, with its stone-ground staples, required a massive buildup of tooth enamel*. The two responses to this problem we studied were shovel-shaped incisors (as I recall, exclusively found with native Americans) and Carabelli's cusp, found only in European populations. Both add valuable surface area to teeth, letting them be used longer in chewing.

So, next time you're chewing gum flatten it out and bite down with your incisors. If you see any "wings" (think a staple set on its side) on the ends, you most likely have an Indian somewhere in your ancestry. If you feel a funny nub or spike-like projection on the inside of your upper second molar, you may also have a German, Brit, or Czech in the woodpile as well.

Ain't science fun?

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* Because there was no way to keep bits of stone from being included into whatever was being ground, products made from milling acted like, well, grinding stones on teeth. It's not uncommon to find skeletons from agricultural societies with teeth ground all the way down into the dentin. Significant erosion, as I recall, could ocurr as early as the mid-20s. Considering the pain from a small cavity, it is left as an exercise for the reader to imagine the feeling of a mouth full of teeth with their tops completely worn off.