Evolution v. Creation Watch: The Cambrian Explosion (545 Million Years Ago), the Cambridge Explosion (1869), and Natural Selection Replaced by the Eschaton?

Here is a depiction of the HMS Cambridge firing a torpedo (Illustrated London News, 1869):

And here’s a fossil from the Cambrian explosion (image source: Wikipedia).

File:DickinsoniaCostata.jpg

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    .

And here’s my question: does the Cambrian explosion (the relatively sudden appearance of most phyla over a 10 million year period) torpedo evolution by random mutation and natural selection? Jerry Fodor and Massimo Piatelli-Palmarini, in their book, What Darwin Got Wrong (2010, pg. 52), think it might:

[M]orphological explosions may well reflect major changes in internal constraints as crucial components in speciation. If so, then the effects of natural selection may well consist largely of post-hoc fine-tuning in the distribution of subspecies and variants (Newman and Bhat, 2008): quite a different kind of account from the one of gradual selection of randomly differing small variations.

University of Chicago geneticist, Jerry Coyne, however, insists that, absent a miracle, the phyla in the Cambrian had to have simpler and common precursors that diversified, like everything else, via good old fashioned mutation and natural selection. The fossil record, being incomplete, is causing us to think in a confused way about this. He presents, as illustration of this confusion, an Intelligent Design argument (in which a phylum is likened to an automobile chassis), and smacks it down:  

[T]he “top down” pattern is precisely what is expected if life resulted from a designing intelligence: humans, who are conscious designer[s], use a top-down strategy in their creations.  Automobiles, for example, have retained the original design of an engine, four wheels, etc., while varying only in detail as time progressed.

This is a clever argument, but of course fails when we have a good fossil record, as in the evolution of mammals from reptiles or of amphibians from fish.  We don’t see fully-evolved mammals appearing suddenly in the fossil record, later spinning off the various groups of modern mammals. Rather, we see a gradual divergence of mammal-like reptiles from reptile-like reptiles, with the major groups of mammals forming later.

In other words, Coyne is suggesting that what is true of classes (mammals and reptiles) surely is true also of phyla (like arthropods and chordates), and therefore the design argument must fail “when we have a good fossil record, . . .”

But that’s the problem, isn’t it? With regard to the Precambrian and Cambrian, it seems we don’t have a good fossil record. Or, rather, perhaps we do, and it’s just not matching our expectations of incremental increases in complexity and diversity via mutation and natural selection.

At the level of class, natural selection, as a chief mechanism of evolution, appears secure. But at the level of phyla, something seems curiously amiss. Like the historic disjunctures represented by the Big Bang and the appearances of life and mind in the universe, the Cambrian explosion seems to be a jump—a saltation, a French Revolution—that “changes everything.” When we talk, for example, about evo-devo, it is the basic body plans (arthropods, chordates, etc.) set in the Cambrian that are conserved. The on-off switching of the hox genes focus on the developmental timing and modular components overlaid upon the basic body plans. Thus, like the Big Bang and the origins of life and mind, the Cambrian explosion looms like an ontological mystery (a mystery of being): how did so much that is beautiful, complex, and essential to subsequent life arrive so suddenly, as if drawn from a magician’s hat?

It makes you want to speculate: are random mutations winnowed by natural selection really up to the task of accounting for the Cambrian explosion? I can’t help but wonder whether Simon Conway Morris is right: that at some level the basic body plans that we see and the consciousness that we experience are inevitable. Perhaps these disjunctive leaps occurred, not contingently, but because the dice are loaded: they are manifestations or arrivals of an eschaton (a divinely ordained historical climax that changes everything). It is mind-boggling, but maybe the universe’s original order is breaking its symmetry and entropically cascading through grand signposts (the Big Bang, the origin of life, the Cambrian explosion, human consciousness) on its way to still other world-shattering discontinuities—other, undreamed of by us, surprises.

Stuart Kauffman seems to think along the lines of the universe as a platform for emergent discontinuities. And, in religious terms, Christians famously await one of these discontinuities (the Second Coming). Rowan Williams, in conversation with Richard Dawkins, sees Jesus’s resurrection as an example of one of those moments in history where “there’s an opening in the world in which the underlying divine action comes through in a fresh way”:

Williams’s proposition of “divine action coming through in a fresh way” is not so much the direct intervention of God into the universe, tinkering with it (though, in crasser forms, it certainly could be). Rather, the proposition can be seen as imagining crucial moments in history (such a the Cambrian explosion) as a “put-up job,” a culmination of what was already, in embryo, present from the beginning (perhaps in the laws of physics and how they would make matter and energy cascade through time). The first miracle—and the only necessary miracle—is the ontological mystery (the mystery of information and being itself, the ground of being, the first order, the first symmetry) that is now entropically reverberating to its climaxes, its eschatons, its “second comings” and secondary explosions.

Or maybe the universe and life are just huge accidents over which we have projected purpose and design. As Jerry Coyne writes in his book, Why Evolution is True (2009, pg. 115):

It is no surprise that early naturalists believed that animals were the product of celestial design, created by God to do their jobs.

Darwin dispelled this notion in the Origin.

Not so fast?

About Santi Tafarella

I teach writing and literature at Antelope Valley College in California.
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8 Responses to Evolution v. Creation Watch: The Cambrian Explosion (545 Million Years Ago), the Cambridge Explosion (1869), and Natural Selection Replaced by the Eschaton?

  1. Gato Precambriano says:

    Hi Santi

    As for the Cambrian Explosion (have I said already that ‘gato precambriano’ means ‘precambrian cat’ in portuguese?) I think you should take a look at PZ Myers’ take on that: The Cambrian Explosion as an evolutionary exemplar.

  2. santitafarella says:

    Cats in the Cambrian! I hadn’t made the link to your joke about what would falsify evolution.

    Thanks for the link. I might talk about it in a separate post.

    —Santi

  3. JCR says:

    It is all about critical mass. We see this in systems today. In the last 100 years we have acquired more scientific knowledge and advancement than in the last 1000. The reason being that we have built the foundations upon which greater understanding can be more rapidly processed – computers, simulations, universities, linear accelerators, etc.

    The cambrian explosion is similar, the basic foundations of life all took a while to build before the cambian. Multi cellular structures, energy producing organelles, etc. Then we start to see predation, a real kick start. A more oxygen rich atmosphere and lungs allowed larger growth and more advances also.

    The idea of critical mass allowing acceleration proves itself in observable ways on a regular basis. The Cambrian Explosion is just one of the oldest and most visible examples.

    • santitafarella says:

      JCR:

      You make an important point about critical mass, but my question is this: is the universe a “put up job” in which these critical masses are designed into the system, or are they contingent phenomena (lucky accidents)? Like the Cambrian Explosion, I suppose you could also say that human consciousness and language are other moments of “critical mass” expressed. And isn’t “critical mass” another way of describing the coming of the eschaton? What else is building up in the universe to a culmination that will take us all by surprise?

      —Santi

      • JCR says:

        I wish I knew :)

        You always make me think by blending the concrete with the conceptual. Concretely, I know these things exist. I have trouble with causation because I am so torn. I am an atheist and a skeptic, part of me says these things are the natural order since they can be seen in so many disparate areas. The ponderer in me feels that the dice are loaded. Life wants to find a way. While science says entropy, observation shows us order within chaos. These things have never meshed in my mind. We see organic molecules on asteroids and in meteors. Even if you attribute life and organics to the default chemical bondings and progression .. why?

        As for where else in the universe, I am even more baffled. From a non-life event side, I am sure there are catastrophes and beauties abound. From a life side, what the hell. Why are we not seeing signs of life elsewhere? It is absurd. We are a nascent species. Are we really the first to pollute the galaxy with radiation (noise). No other life has advanced to the level of manipulation of the atom? Or are they so far ahead of us that they use things we have not even dreamed yet. What we see of life finding a way to exist says that life should be abound in the galaxy .. yet we seem alone. If anything makes me think there is a higher power, our aloneness is it.

    • santitafarella says:

      Gato:

      Well, that phylum link adds another level of complication to the issue, doesn’t it?

      My head is swimming.

      —Santi

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