Cambrian Explosion? NBD

Nick Matzke at Panda’s Thumb thinks the Cambrian Explosion was not a big deal. I think it was a big deal. Here are my top 5 problems with his article:

  1. Section A is titled, “THE “EXPLOSION” TOOK AT LEAST 30 MILLION YEARS, AND WAS NOT REALLY “INSTANTANEOUS” NOR PARTICULARLY “SUDDEN””
  2. No one worth their salt thinks the explosion took that long. Wikipedia says it was 20-25 million years. ID proponents like Meyer are generally talking about a period 20 million years or less. In a class literally called Evolution 101, Berkeley says it took perhaps as little as 10 million years: “In perhaps as few as 10 million years, marine animals evolved most of the basic body forms that we observe in modern groups.”
  3. According to most evolutionary biologists, biological life began about 3.6 billion years ago on earth. If we include chemical evolution under the idea of evolution then we are really looking back to the beginning of the universe 12-14 billion years ago. So yes, 20 million years is pretty much “instantaneous” on a normal evolutionary scale. Within about half of a percent of the timeline of biological life, that is during the Cambrian explosion, 20 of the 26 known animal phyla suddenly entered the fossil record. They appeared already marvelously complex. There is no evidence of slow, gradual change. This is a significant and important finding. Darwin himself in The Origin mentioned that the Cambrian evidence is a “truly…valid argument against” his theory.
  4. Matzke’s own chart, figure 2 from the Peterson et all paper shows the immense growth in the period. It tries to downplay this by hilariously referencing a “Putative Fossil Range.” That is, a series of fossils which have never been discovered and are merely assumed to exist. Wouldn’t it be nice if we could just assume facts like the scientists do? They also attempt to deflate the explosion by cropping the evolutionary timeline in a way that eliminates the huge flat-line of growth after the explosion and before the Ediacaran era.
  5. Matzke conflates ID with creationism and bags on Meyer for stupid stuff like calling Anomalocaris arthropods. Matzke says, “…in fact, anyone actually mildly familiar with modern cladistic work on arthropods and their relatives would realize that Anomalocaris falls many branches and many character steps below the arthropod crown group.” Anomalocaris is an extinct genus of anomalocaridid, a family of animals thought to be closely related to ancestral arthropods. It’s kind of like calling Nimravidae a cat. Not Meyers’ most rigorous statement, but not something to throw a fit about.

So basically, the Cambrian Explosion is a big deal. This is not just what I am saying or what the pro-ID people are saying, this is what a huge number of even mainstream scientists are saying, but I won’t call it a majority as I haven’t seen any surveys or done a thorough literature review. I will toss out a couple articles compiling literature from pro-ID folks and more mainstream folks who don’t support ID but do see problems with traditional evolutionary theory:

Edit 6/12/15: I just found this solid article dealing with the very Matzke article I just addressed. I would also note that the Cambrian Explosion need not be viewed as only a small portion of the early Cambrian. The Cambrian Explosion can be viewed as beginning at the end of the Precambrian and extending into the early Cambrian. It’s the rapid evolution in a small period of time that matters, not whether it was part of one or the other artificial time category.

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2 thoughts on “Cambrian Explosion? NBD”

  1. “The Cambrian Explosion can be viewed as beginning at the end of the Precambrian and extending into the early Cambrian. It’s the rapid evolution in a small period of time that matters, not whether it was part of one or the other artificial time category.”

    And if you count up the time from the beginning of skeletonized forms in the late Precambrian, to the observation of the classic “phyla” — which is the event of interest — you get 30+ million years. Like I said. And the diversification is pretty gradual within that time period, if you actually look at the trace fossil data and the small shelly data, which Stephen Meyer did not.

    Here’s another view, from someone who actually works on early Cambrian fossils — unlike most people who get quoted:

    ‘The “Cambrian explosion” is a poorly-defined term that refers to a period of time some 600–500 [million] years ago (“Geon 5” [Hofmann, 1990]) during which the biosphere, as reflected in the eukaryotic fossil record, underwent a great expansion.’

    -Graham E. Budd (2003). “The Cambrian Fossil Record and the Origin of the Phyla.” Integrative and Comparative Biology, Volume 43, Issue 1, pp. 157-165.

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