Worms ‘r’ us

What’s a philosopher doing writing about science? Willikins has a short article on the idea that bioturbation was a major factor in the Cambrian explosion. I can go with that: the Cambrian and pre-Cambrian seem to have been times when the sea floor was covered with algal mats, and the successful animal forms were grazers who scraped the surface and worms that burrowed through them. Along with changes in atmospheric oxygen, the radical remodeling of the marine substrate were the major biologically induced changes in the environment.


  1. says

    We often note within Evolutionary Biology how broad Darwin was in his writing and research (biogeography, domestic animal breeding, ecology, etc. etc.). His moograph on worms includes a chapter called “The part which worms have played in the burial of ancient buildings” … so yes, he also wrote on archaeology. (Here, about site formation processes of a Roman site)

  2. says

    OT, but I had to comment on one of your random quotes in the sidebar:

    If one were to take the bible seriously one would go mad. But to take the bible seriously, one must be already mad.

    [A. Crowley]

    Good old Uncle Alester. (Actually, he was born Edward Alexander Crowley, but he rebelled against that as thoroughly as he rebelled against Christianity.) He had the misfortune to be born into the rather hard-shelled Plymouth Brethren, and his parents were particularly virulent examples thereof.

  3. says

    I just wanted to say thanks for linking this. The Cambrian fauna are a mild obsession of mine, and this was a theory I hadn’t heard anything about. Once again, PZ, you’ve broadened my horizons.

  4. octopod says

    Cambrian explosion and bioturbation! Have I mentioned how much I love this blog? :-D

    And yes, it does seem likely, considering that bioturbation is essentially what we use to define the beginning of the Cambrian…I didn’t know this was a new theory, actually, now that I think about it. Instead, it’s one of those things we throw around in geobiology courses — opening that reserve of nutrients in the subsurface from buried organic matter and stratified algal mats would increase the available food supply by at least 10x. Come to think of it, I never did understand why people make such a fuss over the improbability of the Cambrian explosion…

  5. Tony D'Andrea says

    (Note: Also posted at John’s site)


    These ideas have been floating around for a number of years about the transformation from a 2D surface to 3D burrowed substrate, primarily by trace fossil/paleontology researchers such as Adolf Seilacher (e.g. Seilacher and Pfluger 1994 (email you want the detailed reference)). This change also represents a fundamental shift in food resources and trophic structure for sediment-dwelling animals. Given the impacts that burrowing animals also have on the sediment chemistry, some authors have speculated that this period may also be an important period in changing how biogeochemical cycling occurred in the Phanerozoic on. This was recently highlighted by a recent paper by Bob Aller (2001, Ch. 11, The Benthic Boundary Layer, Boudreau & Jorgensen (eds.).

  6. Owlmirror says

    Just raising an eyebrow over “Willikins”. But what’s an extra letter in a name, eh, Professor Meyers?