From the wild side

I recommend the article, "The Repeater," by evolutionary biologist Olivia Judson, published January 29, 2008 on the author's "Wild Side" column on the web. It addresses the question, "How evolution repeats—or, what we can learn from the itineraries of sticklebacks." (I've included here one of the photos that illustrate the article. Sticklebacks are small scaleless fish having two or more free spines in front of the dorsal fin.)

Olivia Judson, an evolutionary biologist, is the author of Dr. Tatiana’s Sex Advice to All Creation: The Definitive Guide to the Evolutionary Biology of Sex, which was made into a three-part television program. Ms. Judson has been a reporter for The Economist and has written for a number of other publications, including Nature, The Financial Times, The Atlantic, and Natural History. She is a research fellow in biology at Imperial College London.

The article opens:

Here’s an evolutionist’s dream: 10,000 planet Earths, starting from the same point at the same time, and left to their own devices for four and a half billion years. What would happen? Could you go on safari from one planet to the next seeing an endless procession of wildly different organisms? Or would many of the planets be home to life forms that are broadly similar?

The conventional answer to this question — the one championed by the late Stephen Jay Gould, for example — is that chance events, from mutations to asteroids, play such a large role in evolution that each of the planets would be totally different. And probably, after four and a half billion years, they would be. I wish we could do the experiment, though. It might hold some surprises.