Wednesday, June 22, 2005

Bats and E.T.

Carl Zimmer has a number of good science posts lately, with my favorite being this one about how some bats have become dumber through evolution. Actually their brain-to-body mass ratio has shrunk, but one suspects it will now take them longer to complete the New York Times crossword puzzle.

Biologists and those interested in the Search for Extraterrestrial Intelligence have debated whether evolution towards intelligence is just a fluke here on earth, or something that's likely to happen on other planets with complex life. My amateur impression is that becoming smarter is one of several directions that species branch into. Some primitive mammals got big, some got very small, some evolved to swim, others to climb trees, to glide, or to fly, and some got smarter. Once a species start in one direction, another species might branch off either further in that direction or go in reverse. Fish evolved into amphibians and reptiles living on dry land, and now sea turtles live almost their entire lives in the water. Primitive bats were probably smarter than their earliest reptile ancestors, and now some bats are dumber.

This isn't completely random - becoming smarter is one of several survival strategies animals can use, and competition within and between species could push towards a gradual increase in intelligence. Even if it were random, though, given enough radiation of one species into several species exploiting different survival strategies, we can expect some of those species to get increasingly intelligent over time, both here and on other planets.

I think E.T. is out there, somewhere.

keywords: science, bats

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