Tuesday, February 14, 2012

Intelligent evolution

I am always fascinated to read about the ways in which evolution works to create an integrated and interactive ecology. It's especially interesting to read about the defenses which both animals and plants perfect through the mechanism of natural selection over the course of thousands of years. And not just defenses as such, but also the ways that the bodies of animals - or plants - change over time in order to take advantage of the environment in which they live. That's how the giraffe got its long neck or the elephant its trunk. And, of course, it is how humans developed their upright stance and their big brains.

But how did zebras get their stripes? And why did zebras get stripes?

Well, the obvious answer is that in the tall grasses where they often grazed, the stripes helped to camouflage them and hide them from predators like lions and cheetahs. It turns out though that the stripes also seem to hide them from a much smaller predator.

Scientists have recently completed a study of what kind of hides are most attractive to bloodsucking horseflies. They determined that spotted or solid color coats of animals were most apt to draw the pest, while a striped hide was most repellent to them.

Horseflies are an annoyance to any hoofed animals in their neighborhood but they can be much more than just an annoyance. They can carry deadly diseases, as well, and pass them along to their hosts. Thus, being less attractive to a horsefly can be a positive defense against disease and death. And so, Nature gave zebras, from whom the bloodsucking pests would normally love to feed, a marvelous defense against not only lions and cheetahs, but even the lowly horsefly.

I love science! And I especially love the intelligence of evolution.

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