Monday, October 6, 2008

"Evolution is complete"

It's not news, it's And it's a doozy.

The intro is just a tad odd - opining about the good old days and how the human race is in decline, apparently on "social, moral, and biological levels". They might have well just thrown in this quote:
"Our earth is degenerate in these latter days. There are signs that the world is speedily coming to an end. Bribery and corruption are common, Children no longer obey their parents. Every man wants to write a book, and the end of the world evidently is approaching." - Assyrian tablet circa 2800 BCE"
Really, declining on a biological level? Seriously?

They help make the case with a basic overview of the theory of evolution. Well, a brief but passable explanation, and a couple terrible jokes. And then finally, cutting to the chase:

"As a result, the rate of mutation goes up many times for old fathers compared to young ones. To forecast its future we need to know only how many elderly fathers there will be.

That figure is, in the West, in decline. Today's men start late, but stop early. In Cameroon, almost half the fathers are over 50, in Pakistan about a fifth, and in France only about one in twenty. Young dads mean that the rate of mutation is going down rather than up, and less, not more, of evolution's raw material is being made."

Okay, I'm no geneticist, but I think I see a couple problems here.

#1 - Complaining about young fathers putting the brakes on evolution makes NO sense for the obvious reason that for most of human history, humans have had babies very, very early. We're not talking Bristol Palin early (17), we're talking Mercy ministries early (11), ages so young that it's just barely physically possible.

#2 - I'm not sure where they got the statistics about younger fathers. It wasn't too long ago that they ran an article on increasing numbers of 40+ fathers: "The number of over-40s giving birth in Britain each year has doubled in the past decade to 16,000."

#3 - There's a very good reason why men don't often reproduce late in life: there's a pretty nasty risk of birth defects involved. Mutations may fuel evolution, but they also fuel Down syndrome.

From there, the article drifts into the tedious ancestral histories, eventually getting to an actual point in that modern technology and lifestyles have greatly reduced darwinian pressures and therefore evolution. In that, I agree. I mean, it's not like my neighborhood is hunter/gatherer tribe toughing out drought with a fair amount of man-eating beasts roaming the area. But still, it's far from "complete". Sexual selection, for example, is still going strong.

But the thing that kills me about this question is that whenever people talk about where human evolution is headed, they either imagine X-Men-like superhumans or becoming the prey of giant crows or humanity splitting into utterly ridiculous subspecies.

It's incredibly silly.

Okay, here's what I think will happen (at least on the Nature side of things): you might see a nifty little trick or two (lactose tolerance, sickle-cell anemia, AIDS resistance, increased blood oxygenation at very high altitudes, etc) but nothing earth-shatteringly different. And then we go extinct. The end.

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