A recent paper in BioEssays, “MicroRNAs and metazoan macroevolution: insights into canalization, complexity, and the Cambrian explosion,” admits the lack of a “materialistic basis” — that is, a plausible materialistic explanation — of the Cambrian explosion. As the article states:

Thus, elucidating the materialistic basis of the Cambrian explosion has become more elusive, not less, the more we know about the event itself, and cannot be explained away by coupling extinction of intermediates with long stretches of geologic time, despite the contrary claims of some modern neo-Darwinists.

(Kevin J. Peterson, Michael R. Dietrich and Mark A. McPeek, “MicroRNAs and metazoan macroevolution: insights into canalization, complexity, and the Cambrian explosion,” BioEssays, Vol. 31 (7):736 – 747 (2009).)

The authors give no indication that they themselves support intelligent design (ID), and it seems they are still hopeful for a “materialistic” explanation for the Cambrian explosion, but they nonetheless give a witty nod to some observations and arguments made by ID proponents:

Beginning some 555 million years ago the Earth’s biota changed in profound and fundamental ways, going from an essentially static system billions of years in existence to the one we find today, a dynamic and awesomely complex system whose origin seems to defy explanation. Part of the intrigue with the Cambrian explosion is that numerous animal phyla with very distinct body plans arrive on the scene in a geological blink of the eye, with little or no warning of what is to come in rocks that predate this interval of time. The abruptness of the transition between the ”Precambrian” and the Cambrian was apparent right at the outset of our science with the publication of Murchison’s The Silurian System, a treatise that paradoxically set forth the research agenda for numerous paleontologists — in addition to serving as perennial fodder for creationists. The reasoning is simple — as explained on an intelligent-design t-shirt.

Fact: Forty phyla of complex animals suddenly appear in the fossil record, no forerunners, no transitional forms leading to them; ”a major mystery,” a ”challenge.” The Theory of Evolution — exploded again (idofcourse.com).

Although we would dispute the numbers, and aside from the last line, there is not much here that we would disagree with. Indeed, many of Darwin’s contemporaries shared these sentiments, and we assume — if Victorian fashion dictated — that they would have worn this same t-shirt with pride.

(Kevin J. Peterson, Michael R. Dietrich and Mark A. McPeek, “MicroRNAs and metazoan macroevolution: insights into canalization, complexity, and the Cambrian explosion,” BioEssays, Vol. 31 (7):736 – 747 (2009), internal citation numbers removed, emboldened emphasis added.)

While their article then directly goes on to admit the “elusive” state of any “materialistic basis” of the Cambrian explosion, it doesn’t really offer any explanation for the Cambrian explosion other than a vague mention of the open niche hypothesis and adaptive radiation. The rest of the article focuses on explaining the overall loss of phyla and body plans since the Cambrian, rather than the explosive emergence of new body plans in the Cambrian explosion. At some point, however, neo-Darwinism must account for the origin — an abrupt one at that — of new body plans, not merely the inability to evolve new ones in post-Cambrian times (what they call the “canalizing” of development). It would seem that after this article, the explanation for the origin of the phyla in the Cambrian explosion is no less “elusive” than before it.