Wednesday, May 10, 2006

Cambrian Animal of the Week

Anomalocaris is this week's "Cambrian Animal of the Week." Take a look here or here. This is one of the first complex animals on earth and a hero of the Cambrian Explosion, sometimes reaching a length of six feet. Gotta love this guy- or is it a girl? Made famous by making the cover of Simon Conway Morris's book Crucible of Creation, which was mentioned in my last post. You know, for a Burgess Shale fossil, that is pretty much like making the cover of the Rolling Stone.

The Smithsonian website says this:
This fearsome-looking beast is the largest known Burgess Shale animal. Some related specimens found in China reach a length of six feet! The giant limbs in front, which resemble shrimp tails, were used to capture and hold its prey. A formidable mouth on the undersurface of the head had a squared ring of sharp teeth that could close in like nippers to crack the exoskeleton of arthropods or other prey. With those large eyes and a body half flanked with a series of swimming lobes, this must have been an active, formidable predator!

For more on what this critter means to us, read here or here or here.

You may want to read an old post of mine: The New York Times Teaches the Controversy- And Nobody Got Hurt. Tell me if you think they did a good job of presenting both sides of the debate about the Cambrian Explosion.

Monday, May 08, 2006

Simon Conway Morris Agrees With Me

Maybe the title of this post should read "I Agree With Simon Conway Morris- At Least On One Thing." Here is the one thing: the Cambrian Explosion raises significant questions regarding Darwinian theory and reasonable persons are justified in questioning the validity of macroevolutionary theory on the basis of this evidence.

Morris is a leading paleontologist who was lionized in Stephen Jay Gould's book Wonderful Life because of his work on the Burgess Shale fossils of the Cambrian era. Here is what he had to say about the problems posed by the Cambrian era fossils in his book The Crucible of Creation: The Burgess Shale and the Rise of Animals (1998):
As our knowledge of the Burgess Shale has continued to expand, so it has reopened a whole series of questions that are relevant to the Cambrian 'explosion'. . . . By 1859 the problem had been more clearly articulated by Charles Darwin, in his Origin of Species. Darwin was fully aware that his theory might be difficult to reconcile with the seemingly abrupt appearance of the Cambrian animals. It is a testament both to the prescience of Darwin and the magnitude of the problem that to a considerable extent his articulation of the problem remains compelling and relevant reading today. p. 140-141.

Indeed, how can we explain the origin of so many forms of animal organization in the Cambrian? Did they appear almost simultaneously? Surely there must have been extraordinary mechanisms of evolution responsible for this, mechanisms that no longer operate today? Perhaps even the Darwinian paradigm of evolution, vigorously defended against all attack for more than a century, is now set to crumble before our eyes? Is not the sheer range of animals alive in the Cambrian far in excess of anything we see in modern seas? These are not absurd suggestions made by cranks and eccentrics on the fringes of science, but questions raised by reputable scientists. p. 164.

In the interest of honesty and full disclosure, he then states that in the next chapter he will explore why these ideas appear to be "flawed." And then he attempts to do so. But the rest of the book does not even begin to address all of the problems posed by the Cambrian Explosion. Moreover, I found his explanations fairly narrowly focused and far from convincing.

In any case, I quote him not for the proposition that he thinks "the Darwinian paradigm of evolution . . . is now set to crumble before our eyes." Rather I quote him because he believes that those who question the theory, and certainly those that believe that the Cambrian Explosion is solid scientific evidence that tends to undermine Darwinian theory, are not "cranks and eccentrics on the fringes of science" but that many are "reputable scientists."

While I am sure he is not a signer of the Dissent From Darwin statement, his comments can be viewed as a defense of the reasonableness of those who did sign. It also undermines the position of those who believe that teaching public school students about these fossils is unconstitutional.

* * *

For more on the Cambrian Explosion fossils, read here.