Thursday, January 10, 2008

"Let Wallace Hang"

Says evolutionary biologist, Olivia Judson, a familiar denizen of these environs. On his birthday, January 8, she went to the British Museum, where busts and portraits of all of the great scientists of the 19th century are lionized. But Alfred Russel Wallace's portrait was in storage.

By way of signaling Wallace's great contribution to science -- as one who sent Darwin a letter containing a manuscript outlining the ideas evolution by natural selection and who thus stimulated Darwin, who betook himself to the drafting table to publish "On The Origin of Species" eighteen months later -- Judson makes two great points.

The first is to point out that the infelicitous phrase "survival of the fittest" is a tautology: Who survives? The fittest. Who are the fittest? Those who survive.

The second is to explain natural selection so that anyone can understand it. She writes:

"The idea is simple. Far more organisms are born than can survive. Among small song birds such as blue tits (Cyanistes caeruleus), for example, each female can lay as many as ten eggs in a clutch, each year. Yet the blue tit population doesn’t grow gigantically every year; on the contrary, it stays more or less the same. Every year, then, most blue tits die. They become food for squirrels, or cats, or maggots. Any bird that has attributes that help it to survive — sensitive hearing, a beak well suited to breaking into seeds, a knack for catching spiders and caterpillars — will have an edge over its less endowed fellows, and will be more likely to leave offspring. If those attributes have a genetic component, the offspring may (depending on how the genetic dice roll) inherit them. Over time, different populations of the same species will face different pressures and begin to diverge."

And, the rest is history. That divergence leads to the gradual evolution of different species and the profusion of life forms that inhabit the Earth today. And, it evolves by dialectic, as it were, and not purpose.

I'll leave you to read Wallace's entreaty of 1863 to preserve nature, in language as urgent as any written by Al Gore.