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[Non-ceph] Bioturbation and the Cambrian explosion


O. bimaculoides
Oct 19, 2006
So I saw on scienceblogs.com this morning the following article:
Bioturbation: a fresh look at Darwin’s last idea. which will be coming out soon in Trends in Ecology and Evolution. Briefly, it wants to raise the idea of the Cambrian explosion being caused by the invention of bioturbation.

This makes sense, of course. Bioturbation is really the marker ichnofossil by which we recognise the beginning of the Cambrian -- Skolithos in particular, IIRC -- that is, when some worm or other got the idea that they might try their hand at sediment-mining. This, of course, would've multiplied the available biomass for eating by 10 or 100 times at least -- buried organic materials and subsurface algal mats both would have become fair game for burrowers. (I recall once complaining to some prof in the department that the Cambrian is basically defined as when the fossil record begins getting interesting but also as when it begins getting difficult to read.) Anyhow, it's clearly a good reason for there to suddenly be a huge population explosion and radiation, because there would suddenly be a tremendous increase in the available food supply because the remains of creatures going at least thousands of years back would be available to eat...it's like the organic carbon Renaissance or something.

I'm rather confused, now, though, over whether it's actually a new idea in the literature, or whether I've just never seen its antecedents. See, it's certainly been bandied about enough in my geobiology classes at Caltech, such that I thought it was a common notion; however, now that I think about it, I can't think of actually having read it anywhere before today. However, it's a sufficiently obvious conclusion that I'm happy it's been published if it never has before!

Anyhow, I thought you lot might find it interesting at least, and furthermore that someone ought to be able to answer my question, which is this: Is this a new idea in the literature, or am I just behind on my reading?


Larval Mass
Dec 31, 2006

That makes a lot of sense to me, too. Though I've heard a number of theories about the causes of the Cambrian Explosion. One theory was that the development of eyes put a lot of evolutionary pressure on all types of animals (predators and prey), though I admit I don't know too much about that. Then there was something about rising oxygen levels... maybe I should do some actual research :roll:

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