Natural selection is only a breath away

Natural selection is always right at your elbow, ready to remove some of the variation from the population, and that variation might be you.

It was almost me in 1993. It had been a very moist spring, and the mouse populations in much of the country had exploded. It was my first summer to teach field botany and environmental science at the Wheaton College Science Station uphill from Rapid City, South Dakota, in the Black Hills. I did not know that there was anything unusual about finding mouse feces in the bedroom drawers when we opened the cabins from their winter dormancy. I just assumed that was what always happened. I cleaned out the drawers without taking any particular precautions.

A couple of weeks later, the news broke about the Hantavirus that killed healthy young Native Americans in the Four Corners region, a relative of the Hantaan virus that had killed American soldiers in Korea during the war. The Four Corners victims inhaled dust that had virus from the feces of the very species of mouse that had overwintered in my cabin. Perhaps the droppings in my cabin had not been dusty; perhaps the mice were not infected; or perhaps it was just blind luck.

I am not talking about the Darwin Awards, in which people suffer severe consequences for stupid acts. (The Darwin Awards claim to be natural selection in action, but this is not true, as I explain in my Encyclopedia of Evolution.) I am talking about things that normal people do, and are avoided only by dysfunctionally cautious people, the ones who imagine germs everywhere. They have a point—germs, and all other threats to survival, could be anywhere.

As I will explore in later entries, evolution is not a march towards perfection. It is the survival of the luckiest—perhaps because of their genes, and perhaps not.

When was your last brush with natural selection?