Showing posts with label Evolution. Show all posts
Showing posts with label Evolution. Show all posts

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.

Wednesday, January 2, 2008

Jump Starting Evolution

Great new blog on evolutionary biology, The Wild Side. Actually, the resumption of an earlier one.

Today's post is about how to breed Bluefin Tuna in a Mackerel mom.

And for those of us who worry about basic sexuality, it turns out that germ cells and even spermatogona -- which are the germ cells developed a bit further down the road of complexity -- will turn into ovaries if implanted in a female and continue being male if implanted in a male.

All of which shows that the basic genetic drivers are the same even after many millions of years of separate evolution. But, read on . . .

Why Death is Essential to Life

Olivia Judson, an evolutionary biologist at Imperial College London, who writes for the Economist, Nature, the Financial Times, the Atlantic and Natural History (and now the New York Times) has written a superb post on death. The role of death in nature. Why death is essential to life. In fact indispensable.

The post is so good, it makes you want to try it. Not permanently, of course.

The one question she doesn't answer is why do we humans focus so much on the hereafter. Or at least on living indefinitely -- viz Ted Williams. Of course, she doesn't explain why we have an imagination, either. But that is surely for another post.