Friday, January 07, 2005

Icons of ID: (Cambrian Explosion) The Cambrian Explosion

Original Publication

Dembski's recent lamentations about what he considered the selective use of data by evolutionists (googlewars) motivated me to look in some more detail at how ID proponents are handling topics such as the Cambrian Explosion. My findings conclude that ID proponents are still confused about the Cambrian explosion, the fossil record, and the molecular data which contradicts their cartoonish portrayal of the Cambrian. Based on selective 'evidence' and poor scientific arguments, the impression is created that the Cambrian explosion is a problem for evolutionary theory or supportive of intelligent design. Neither assertion is true -- unless one accepts that Intelligent Design is all about ignorance. The lack of any scientifically relevant hypothesis by Intelligent Design to explain the Cambrian explosion exemplifies the scientific vacuity of ID, and I won't even mention the theological risks.

I was initially drawn to the Cambrian Explosion because Intelligent Design theorists had presented it as irrefutable proof of a designer. But after looking into the matter, it seems more like the Cambrian Explosion is a proving ground for evolutionary theory. Rather than a paucity of Precambrian fossil evidence, there is an abundance of it. Rather than throwing in the towel when faced with the rapid appearance of biological variation, scientists have come up with numerous theories explaining how the explosion of life could have happened. In all of this, I find myself disillusioned by the ID proponents. It seems that they too often distort the facts, or outright lie, to ‘prove’ their position. How can there ever be a valid search for truth if information is intentionally withheld or misrepresented?


Ironically Meyer argues that
When credible experts disagree about a controversial subject, students should learn about the competing perspectives.

The irony is that there are no credible experts who disagree and present a competing scientific perspective.

Or as Kevin Padian in The Talented Mr. Wells argues:

Ask how Wells and his colleagues will replace evolution with Intelligent Design, and where the peer-reviewed research for it is. Have them explain exactly who the Intelligent Designer is, exactly when and where He (She? It? They?) intervened in the history of the Earth and its life, and exactly how this can be shown to everyone’s satisfaction. Nobody here but us scientists? Then let’s make Intelligent Design a testable hypothesis and see how robust it is.

Meyer and Campbell write:

First, some scientists doubt the idea that all organisms have evolved from a single common ancestor. Why? Fossil studies reveal "a biological big bang" near the beginning of the Cambrian period (530 million years ago) when many major, separate groups of organisms or "phyla" (including most animal body plans) emerged suddenly without clear precursors. Fossil finds repeatedly have confirmed a pattern of explosive appearance and prolonged stability in living forms -- not the gradual "branching-tree" pattern implied by Darwin's common ancestry thesis. Discoveries in molecular genetics and embryology have also challenged universal common ancestry.

Controversy over life's origins Students should learn to assess competing theories San Francisco Chronicle Open Forum December 10, 2004

As usual with Meyer, it seems to be largely a rewrite of Meyer's Incorporate Controversy into the Curriculum Atlanta Journal Constitution, February 15, 2004

There are many problems with this statement. While I can appreciate the creationist interpretation given to these data by Meyer, a more scientific investigation quickly shows that there is little support for his position. Valentine, an expert on the Cambrian explosion, author of "On the origin of phyla" and often quoted by ID proponents writes:

The title of this book, modeled on that of the greatest biological work ever written, is in homage to the greatest biologist who has ever lived. Darwin himself puzzled over but could not cover the ground that is reviewed here, simply because the relevant fossils, genes, and their molecules, end even the body plans of many of the phyla, were quite unknown in his day. Nevertheless, the evidence from these many additional souces of data simply confirm that Darwin was correct in his conclusions that all living things have descended from a commmon anscestor and can be placed within a tree of life, and that the principle process guiding their descent has been natural selection.

The data on which this book is based have accumulated over the nearly century and a half since Darwin published On the Origin of Species, some gradually, but much in a rush in the last several dedades. I have been working on this book for well over a decade, and much of that time has been spent in trying to keep up with the flood of incredibly interesting findings reported from outcrops and laboratories. I am stopping now not because there is a lull in the pace of new discoveries (which if anything is still picking up), but because there never will be a natural stopping place anyway, and because the outlines of early metazoan history have gradually emerged from mysteries to testable hypotheses.

Valentine On the Origin of Phyla 2004: Preface

In fact (recent fossil) data as well as molecular genetic data do not support the creationist interpretation of Meyer et al.

Meyer, author of the The origin of biological information and the higher taxonomic categories. in Proceedings of the Biological Society of Washington 117, 213–239 is critically reviewed in the Paleontology Newsletter:

Many readily available papers that depart significantly from his conclusions are omitted without excuse, and the logic of his arguments is not always as tight as it should be. On the most general level, Meyer doesn’t understand the bare-bones mechanics of natural selection acting on ‘random’ variation.

The tainting of Proc. Biol. Soc. Wash. Ronald Jenner the paleontology newsletter (57)

for more details as to the many problems with Meyer's arguments see Meyer's Hopeless Monster.

Meyer may claim that 'a few scientists' have a particular viewpoint of the Cambrian explosion but other than a foundation in creationist rethoric, his viewpoints have limited scientific relevance (see for instance a review of the Cambrian by Christian scientists Keith B Miller [1>). Certainly the suggestion that such ideas deserve to be discussed in a highschool curriculum does a disservice to both science education as well as science itself.

What is worse is that Meyer artfully conflates two issues, namely the Cambrian explosion and the issue of a single common ancestor. First of all let it be clear that Darwinian theory nor Neo-Darwinian theory requires a single common ancestor. Anyone familiar with Darwin's writings would be aware of his position on these issues.
The evidence of common descent however is extremely solid as is described in full detail in Douglas Theobald's 29+ Evidences for Macroevolution The Scientific Case for Common Descent.

Some relevant resources

  1. Icons of ID: Carl Woese the final word? by Pim van Meurs
  2. The Precambrian to Cambrian Fossil Record and Transitional Forms by Keith B. Miller editor of Perspectives on an evolving creation

    There is much confusion in the popularized literature about the evidence for macroevolutionary change in the fossil record. Unfortunately, the discussion of evolution within the Christian community has been greatly influenced by inaccurate presentations of the fossil data and of the methods of classification. Widely read critiques of evolution, such as Evolution: A Theory in Crisis by Denton,1 and Darwin on Trial by Johnson,2 contain serious misrepresentations of the available fossil evidence for macroevolutionary transitions and of the science of evolutionary paleontology. In "On the Origin of Stasis by Means of Natural Processes," Battson similarly does not accurately communicate the rapidly growing body of evidence relevant to the Precambrian/Cambrian transition.


    The above discussion shows that the presentation of the Precambrian to Cambrian fossil record given by Battson does not reflect our present understanding of the history of life.32 Many metazoan groups appeared before the Cambrian, including representatives of several living phyla. Furthermore, the many small scale, plate, and spine-bearing organisms of the earliest Cambrian, while sharing characteristics with several living phyla, are also similar enough to each other to be classified by some workers into a single phylum.33 Even when the metazoan fossil record for the entire Cambrian is considered, the morphological disparity cannot be equated with that of living organisms, unless the subsequent appearance of all vertebrate and insect life be ignored. In addition, many living phyla, including most worm phyla, are unknown from the fossil record until well into the Phanerozoic.34 Thus, to claim the near simultaneous appearance of virtually all living phlya in the Cambrian is not an objective statement of the fossil evidence but a highly speculative, and I believe unsupported, interpretation of it.

  3. Taxonomy, Transitional Forms, and the Fossil Record Keith B Miller

  4. The literature speaks of "horizontal" change, which is acceptable because it is within the "kind." Although microevolution can explain horizontal change, evolution taking place "within a kind" is limited because genetic variation is limited: It is not possible to derive one kind from another. "Basic body plans," as creationists call them, are distinct from one another, and thus "vertical" changes between kinds cannot occur (Ramm 1955). In antievolution literature, vertical change equates with macroevolution, or evolution above the species level. The basic body plans of major phyla which appear in the so-called Cambrian explosion are seen by most Old Earth Creationists as evidence of Special Creation.
    Antievolutionism and Creationism in the United States, NCSE Resource

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