Monday, April 11, 2011

Consider the Snail

Irish Snail

Evolution does not work in the way most people think.

Consider the case of the lowly snail. Can you imagine a more pathetic creature?

It is faced with a great deal of natural disadvantages. It is small enough that I can (and sadly sometimes do) tread on them by accident. They have a shell for protection, which is scarcely able to shield them from any serious predator trying to eat them.

And most importantly, they move more slowly than just about any creature other than the sloth. Their ability to escape from danger is, to all intents and purposes, nil. How do they even get around? It must take them all day to move a few metres.

Most people's conception of evolutionary success roughly correlates with 'being at the top of the food chain' or 'not having any natural predators'. If that's the case, you're sweet! Nothing can get you.

But evolution doesn't operate that way. The issue is not the chance of an individual being killed, but the chances of the species being killed that drives extinction. Beef cattle get slaughtered and eaten at a rate of roughly 100%. By contrast, beef cattle face an extinction probability of ~=0% as long as humans desire to farm them for meat purposes.

Consider a creature the exact opposite of the snail. A predator that is eaten by nobody. Fast, agile, and able to defend itself against lots of potential aggressors. The top of the food chain, preying on a variety of smaller animals.

A creature, in other words, like the Sabre Tooth Tiger.

The sabre tooth tigers entered the landscape around 42 million years ago, and became extinct around 11,000 years ago.

Snails, by contrast, have been around about 600 million years, and they're still going strong.

As Khrushchev said, "We will bury you".

The snails has outlived many species who ate it, crushed it, and wantonly killed it. It seems quite likely to outlast us too.

You may step on them or cook them in garlic, but you may be surprised to find one day in a nuclear winter that the joke is on you. The snails will be just fine.

Evolution has a funny sense of humour like that.

(image credit)

No comments:

Post a Comment