Our current model for evolution and development is that small changes in the regulation and timing of key developmental genes are responsible for big phenotypic differences, including new animal body plans. The data shows that all the animal phyla have similar genes and that there aren't very many genes whose origins can be traced to the Cambrian.
... those ignorant of history are not condemned to repeat it; they are merely destined to be confused.
Stephen Jay Gould
Ontogeny and Phylogeny (1977)This model was popularized by Stephen Jay Gould in his 1977 book Ontogeny and Phylogeny. Meyer disputes this model. He claims that massive amounts of new information (= new genes) arose at the time of the Cambrian explosion. He claims that this cannot be explained by any naturalistic means; therefore, god(s) must have made those strange Cambrian animals. (Presumably, the gods are also responsible for making them go extinct.)
Charles Marshall, a paleontologist at UC Berkeley (USA) wrote a critical review of Darwin's Doubt [When Prior Belief Trumps Scholarship]. Here's part of what Marshal wrote in September 2012.
His [Meyer's] case against current scientific explanations of the relatively rapid appearance of the animal phyla rests on the claim that the origin of new animal body plans requires vast amounts of novel genetic information coupled with the unsubstantiated assertion that this new genetic information must include many new protein folds. In fact, our present understanding of morphogenesis indicates that new phyla were not made by new genes but largely emerged through the rewiring of the gene regulatory networks (GRNs) of already existing genes (1). Now Meyer does touch on this: He notes that manipulation of such networks is typically lethal, thus dismissing their role in explaining the Cambrian explosion. But today's GRNs have been overlain with half a billion years of evolutionary innovation (which accounts for their resistance to modification), whereas GRNs at the time of the emergence of the phyla were not so encumbered. The reason for Meyer's idiosyncratic fixation with new protein folds is that one of his Discovery Institute colleagues has claimed that those are mathematically impossibly hard to evolve on the timescale of the Cambrian explosion.A Christian radio station in the UK decided to host a debate between Stephen Meyer and Charles Marshall. The full debate can be seen in the video at the bottom of this post.
As Meyer points out, he is not a biologist; so perhaps he could be excused for basing his scientific arguments on an outdated understanding of morphogenesis. But my disappointment runs deeper than that. It stems from Meyer's systematic failure of scholarship. For instance, while I was flattered to find him quote one of my own review papers (2)—although the quote is actually a chimera drawn from two very different parts of my review—he fails to even mention the review's (and many other papers') central point: that new genes did not drive the Cambrian explosion. His scholarship, where it matters most, is highly selective.
At one time during the debate, Marshall says that Meyer's view of molecular biology is stuck in the 1980s. What he means is exactly what he wrote in his review. Meyer simply doesn't understand the key aspects of modern EvoDevo and he certainly doesn't understand the massive amounts of evidence supporting that model. Marshall is right. Meyer read some of the 1980s papers on regulatory genes in Drosophila but he completely missed the point. Here's what Meyer says in his book (page 315),
Despite the enthusiasm surrounding the field, evo-devo fails, and for an obvious reason: it's main proposal, that early-acting developmental mutations can cause stably heritable, large-scale changes in animal body plans, contradicts the results of one hundred years of mutagenesis experiments. As we saw in Chapter 13, the experiments of scientists like Nüsslein-Volhard and Wieschaus have shown definitively that early-acting body-plan mutations invariably generate embryonic lethals—dead animals incapable of further evolution, The results of these experiments have generated the dilemma for evolutionary biologists that John McDonald aptly described as the "great Darwinian paradox." Recall that McDonald noted that early-acting regulatory mutations do not produce viable alterations in form that will persist in populations, as evolution absolutely requires. Instead, these mutations are eliminated immediately by natural selection because of their invariably destructive consequences.During the debate, Meyer seems to concede that there are reasonable models of the evolution of animals that do not require explosive amounts of new information during the Cambrian. This contradicts and refutes the key argument of his book.
Watch this video (below) of Stephen Meyer explaining what happened during the debate [Video: Stephen Meyer Reflects on the Debate with Charles Marshall]. You will see a typical IDiot strategy at work. Whenever an important, credible scientific expert takes notice of their views, that counts as vindication of a sort. It means that what they (IDiots) are saying must be scientific. It means that their crazy ideas must have some respect in the scientific community. (Marshall was too polite for my taste, although he did make the point that Stephen Meyer is not a biologist.)
This is one of the reasons why you should not debate IDiots. It just makes them look good. The other reason is that they will always spin the results in subsequent publicity campaigns in order to make it look like they did much better than they really did.
Here's the debate...