By MOISES VELASQUEZ-MANOFF via The New York Times
Wheat was first domesticated in southeastern Anatolia perhaps 11,000 years ago. (An archaeological site in Israel, called Ohalo II, indicates that people have eaten wild grains, like barley and wheat, for much longer — about 23,000 years.)
Is this enough time to adapt? To answer that question, consider how some populations have adapted to milk consumption. We can digest lactose, a sugar in milk, as infants, but many stop producing the enzyme that breaks it down — called lactase — in adulthood. For these “lactose intolerant” people, drinking milk can cause bloating and diarrhea. To cope, milk-drinking populations have evolved a trait called “lactase persistence”: the lactase gene stays active into adulthood, allowing them to digest milk.
Milk-producing animals were first domesticated about the same time as wheat in the Middle East. As the custom of dairying spread, so did lactase persistence. What surprises scientists today, though, is just how recently, and how completely, that trait has spread in some populations. Few Scandinavian hunter-gatherers living 5,400 years ago had lactase persistence genes, for example. Today, most Scandinavians do.
Here’s the lesson: Adaptation to a new food stuff can occur quickly — in a few millenniums in this case. So if it happened with milk, why not with wheat?
The sun sets on a field in southern England. When it rises again the following morning, that field has been transformed into an enormous work of art. A large section of the crop has been tamped into a pattern of circles, rings and other intricate geometric shapes. But who created it?
Are crop circles the work of alien visitors? Are they a natural phenomenon, created by electrically charged currents of air? Or are they elaborate hoaxes perpetrated by savvy, talented and very determined circlemakers? Believers and naysayers each have their own theories, but the truth remains elusive.
Keep Reading: HowStuffWorks “How Crop Circles Work”.