Stickleback fish and life on other planets

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.

That's how Olivia Judson, an evolutionary biologist and terrific science writer starts out her blog entry on the NYT this week. This is her January 29, 2008 pot entitled "The Repeater." The questions she raises speak volumes to the complexity of the question of life elsewhere in the universe and what form - or forms -it may take. As is generally true with this whole question, what appears obvious isn't so obvious at all.