Thursday, 30 April 2009

Mass extinction and evolution


I blame Beowulf for my forgetting to post about Save the Frogs Day on Tuesday. Here, belatedly, is a link to a fascinating video about what is happening to amphibians today, ‘the greatest mass extinction since the dinosaurs’ as the filmmakers say. The Thin Green Line explores the different causes of frog death intelligently, including chytrid, changes in land use, climate change and pollution of watercourses. An unexpected pleasure is the opportunity to hear from scientists working around the world to protect species. I was moved by these individuals’ sensitivity and heroism.

So rather than repeating the tragic facts about this die-off I thought it might be worth exploring the issue of how man-made extinction relates to evolution. You don’t have to talk to many people about extinction before someone says, but isn’t that evolution? It emerges in the comments of this excellent site every now and then. The argument goes, the species dies because it isn’t ‘fit’ enough and it isn’t our role to interfere. I’ve been trying to shape some responses to this argument but am very curious to hear any other views on the subject. Here are mine:

1. Responsibility

The mass extinction taking place now is anthropogenic, directly caused by humans. It sounds simple to say we shouldn’t interfere with the process but it is our interference that is causing the deaths in the first place.

While we are merely animals participating in evolutionary processes we have also developed consciousness about ourselves and our actions, which means we can take responsibility for our behaviours. In this case we know we are killing other species so have to ask whether that’s something we want to do. It doesn’t make any difference that those species would eventually die in the course of evolution, just as mortality doesn’t justify murder.

2. Pace

The changes we are bringing about in land use, climate, introduction of invasive species and extraction of prey or pest species from ecosystems are happening at such a rapid pace that species cannot respond to them by evolution. Evolution is just too slow. In fact the changes in climate and land use are happening so fast that species cannot even respond by migration because of the slow rate at which plants travel (this is really well explained here).

3. Evolution

It’s obviously tempting to use the concept of evolution as if it was thoroughly understood with a brief reference to survival of the fittest and the selfish gene. It’s not really surprising that those aspects of the idea became so persuasive in colonial nineteenth-century Britain and the capitalist west. Evolution is a scientific theory of real beauty, of the sort that once you hear it it’s hard to understand why it took so long to discover, but that doesn’t mean that its processes are fully understood. We get a bit confused when using the word ‘fit’ as if it referred only to athletic ├╝ber-species rather than to the ones that are most ‘fitting’. In a society less governed by cultural prejudice (or the belief in a worldwide movement towards a single type of society under the banner of progress) and by financial greed perhaps Lovelock’s Gaia theory would have been taken more seriously. He believes that climate change will prove him right, the terrible experiment to test his theory, and it may be so. At any rate, there are other and more complex models for evolution than the selfish gene, theories that consider species from an ecological or group perspective, such as Edward Wilson’s work on superorganisms.

Among the many blessings marriage to a string-theorist has brought has been the chance to learn how a theory that describes the world can be a thing of real wonder. But that doesn’t make such a theory a conceptual endgame. In fact I think an idea like evolution or the second law of thermodynamics moves my husband far more than any poem can move me (even Beowulf), partially because of those ideas’ inherent truth and elegance, but perhaps also because, just as thrilling, they suggest more thinking to be done, that there are more such ideas out there.

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