How brief was the period in which the Cambrian phyla suddenly appeared?

The Cambrian explosion refers to the sudden appearance of new body plans in the fossil record. ID proponents think that the period is between 5-10 million years at the most. Naturalists want to stretch out the period in which the body plans appear to tens of millions of years. The two sides can’t both be right. What’s the truth?

Evolution News has the answer.


To establish the length of the most explosive period of innovation within the Cambrian explosion itself, Meyer cites the work of MIT geochronologist Samuel Bowring and his colleagues as well the work of another group led by Smithsonian paleontologist Douglas Erwin. The Bowring-led study showed that (in their words) “the main period of exponential diversification” within the Cambrian lasted “only 5-6 million years” (emphasis added). Meyer explains:

An analysis by MIT geochronologist Samuel Bowring has shown that the main pulse of Cambrian morphological innovation occurred in a sedimentary sequence spanning no more than 6 million years. Yet during this time representatives of at least sixteen completely novel phyla and about thirty classes first appeared in the rock record. In a more recent paper using a slightly different dating scheme, Douglas Erwin and colleagues similarly show that thirteen new phyla appear in a roughly 6-million-year window. (p. 73)

[…][T]ake a look first at the following figure that Bowring and his colleagues included in their definitive 1993 article, published in the journal Science. They use radiometric methods to date the different stages of the Cambrian period, including the crucial Tommotian and Atdabanian stages in which the greatest number of new animal phyla and classes arise. Note that the so-called Manykaian stage of the Cambrian period lasts about 10-14 million years. Note also that the main pulse of morphological innovation didn’t begin during this stage but rather during the Tommotian and Atdabanian — a period that they describe as taking between “5 to 10 million years,” and in a more detailed passage as taking about 5-6 million years.

[…]In the figure above, the Tommotian and Atdabanian stages of the Cambrian period together span only about 5 million years, starting at about 530 and ending about 525 million years ago. Bowring’s figure also depicts the total number of classes and orders present at any given time during the Cambrian period. The biggest increases in morphological innovation occur during the Tommotian and Atdabanian stages. Indeed, during this period the number of known orders nearly quadruples. Moreover, Bowring and his colleagues also make clear that this period corresponds to the main pulse of Cambrian morphological innovation as measured by the number of new phyla and classes that first appear. They note that, while a few groups of animals do arise in the earliest Manykaian stage of the Cambrian, the most rapid period of “exponential increase of diversification,” corresponding to the Tommotian and Atdabanian stages, “lasted only 5 to 6 m.y.”

You can see the figure they are reference in the Evolution News article.

Also, check out these clips that explain the Cambrian explosion:

Part 1:

Part 2:

The first clip features James Valentine, a professor of biology at the University of California who just co-authored a new book on the Cambrian explosion and is not a proponent of intelligent design.

The consensus among scientists regarding the period of time in which the new body plans appear is 5-6 million years. Biologically speaking, that’s a blink of an eye. You aren’t going that kind of complexity and innovation in such a short period of time any more than you can expect to win the lottery by buying 5-6 million tickets when the odds of winning are 1 in a googol (10 to the 100th power – 1, followed by 100 zeroes). You don’t have enough lottery tickets to make winning the lottery likely. Similarly, 5-6 million years is not enough time for naturalistic mechanisms to code brand new body plans from scratch. It would be like trying to research and write a Ph.D thesis during a single lunch hour. It’s just not enough time to produce the amount of information that’s required.

8 thoughts on “How brief was the period in which the Cambrian phyla suddenly appeared?”

  1. “5-6 million years is not enough time for naturalistic mechanisms to code brand new body plans from scratch.”

    There is much more that could be said in response, but instead I will ask a simple question: Is that enough time for evolutionary mechanisms to do the job when nature is under the providential control of a sovereign Creator? In other words, what about evolutionary creationism?


  2. The problem is the moment you use the term, you’re not talking about evolution anymore. The definition of evolution specifies that it is undirected natural causes and pre-supposes materialism/naturalism. It precludes the word evolution by definition, as nothing happened by chance or accident and there is in fact something more than the material in the universe. The very term is therefore self-contradictory and self-defeating.

    In any case, the moment you include a super being, you are in fact positing Intelligent Design – that is, that everything that is came into existence by the work of an intellect. There are plenty of old earth creationists who espouse Intelligent Design, as it need not be linked to any particular time period or even any particular religion in and of itself. It is the assertion that natural variance and probability cannot account for the complexity and variety of life that exists, and that a designer or intellect can.


  3. I appreciate your deliberate reply, Water Rat, but I think there is a misunderstanding.

    1. Evolution is “by definition” undirected and naturalistic only in the context of evolutionary naturalism, which I understand was the context of the original article. That is why my question had posed an antithesis to evolutionary naturalism, asking whether the argument still holds when the context is instead evolutionary creationism. In that context, you see, evolution is no longer defined as undirected and naturalistic but in fact a Christological creation.

    2. Unless, of course, you had science in mind when you said that evolution specifies that it is undirected and presupposes naturalism, in which case my answer would be slightly different. Scientifically speaking, evolution specifies nothing of the sort because the question is categorically unscientific, which is to say that whether evolution is guided or unguided is not falsifiable even in principle—not to mention the existence and nature of God (with respect to whether evolution is naturalistic). It is categorically impossible to control for God’s providence, thus science cannot address how nature behaves with and without God’s creative and sustaining power. The question is beyond the limited competence of scientific inquiry.

    3. And the evolutionary creationism I am talking about is radically, fundamentally opposed to the positions argued by Intelligent Design (ID), which always has this troubling aversion to identifying and defending the only true and living God who created all things in Christ, as you indicated yourself (e.g., “the work of an intellect”). When it comes to God, the faith of Christ, scripture, a theology of creation, redemptive history and so much more, ID could not be any more opposed to the language of the Bible and the Christian faith. (And let’s also not forget that ID is itself opposed to scientific theories of evolution. The opposition between ID and evolutionary creation is mutual.)


    1. Evolutionary creationism is fully naturalistic evolution, scientifically speaking. The creationism in the phrase is undetectable by science, so it might as well not be there.

      The atheist and the evolutionary creationist agree on what science shows: namely, that UNGUIDED natural forces are fully capable of accounting for everything we see in nature. The “creationism” is superfluous, scientifically speaking.


      1. First, to describe evolutionary creationism as naturalistic is to speak nonsense, for “creationism” precludes naturalism and dysteleology (unguided) from the outset. As Denis Alexander wrote, “Naturalism is the philosophy that there is no God in the first place, so only an atheist can provide truly naturalistic explanations for anything” (2008, 186).

        Second, evolutionary creationism is not a scientific theory or research program at any rate. Rather, it is a theological view about how to understand the science of evolution within a biblical framework—which, again, precludes naturalism and dysteleology. Alexander again: “The evolutionary creationist is one who has a very firm belief in God’s sovereignty over the whole created order, worked out in his plan and purposes for both creation and redemption” (2008, 181). Fully naturalistic? Not even close. References could be multiplied generously.

        Christians should be alert to the vast difference between science and naturalism and prepared to remind others about this difference, as Howard Van Till wrote. “Sloppy rhetoric should not go unchallenged” (1999, 176).

        Alexander, Denis R. (2008). Creation or Evolution: Do We Have to Choose? Oxford, UK: Monarch Books. (pp. 181 and 186).

        Van Till, Howard (1999). “The Fully Gifted Creation.” Three Views on Creation and Evolution, edited by J. P. Moreland and John Mark Reynolds. Grand Rapids, MI: Zondervan.


        1. Just to be clear, theistic evolution is naturalistic evolution, scientifically speaking. The theism comes as autobiographical details of the theistic evolutionist, and has nothing to do with the science. I.e. – a theistic evolutionist doesn’t think that God actually does anything that science can detect, he just talks about his church attendance and his favorite hymns and how he went to church with his mother. But it does not work scientifically. Scientifically speaking, he is an atheist.

          It’s so funny that you quote Howard Van til, because he is giving talks to atheist groups now:


          Click to access ODoRs.pdf

          FROM CALVINISM TO FREETHOUGHT: The Road Less Traveled
          by Howard J. Van Till

          Professor of Physics and Astronomy, Emeritus
          Calvin College
          Presented 5/24/2006 for the Freethought Association of West Michigan
          Lightly edited 5/26/2006

          Precis: Born into a Calvinist family, shaped by a Calvinist catechism training, educated
          in the Calvinist private school system, and nurtured by a community that prized its
          Calvinist systematic theology, I was a Calvinist through and through. For 31 years my
          teaching career was deeply rooted in the Calvinism I had inherited from my community.
          During most of that time it was a fruitful and satisfying experience. Nonetheless,
          stimulated in part by the manner in which some members of that community responded to
          my efforts to practice what I had learned from my best teachers, I eventually felt the need
          to extend my intellectual exploration into philosophical territories far outside the one
          provided by Calvinism. Did I complete the lengthy journey from Calvinism to
          Freethought? The listener will be the judge.


          He’s abandoned Christianity publicly now. That’s what a theistic evolutionist is, an atheist with excellent PR when facing theists.


          1. Theistic evolutionists differ from atheists in the way that wolves in sheep’s clothing differ from other wolves.


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