by Carolyn Dane
by Simon Conway Morris
Oxford University Press, 1998
Some of you may recall Stephen Jay Gould's 1989 book Wonderful Life about the weird and wonderful animals of the Cambrian explosion as found in the Burgess Shale (in British Columbia). They have names like Hallucigenia, Wiwaxia, and Anomalocaris, the latter being a fierce predator about 3 feet long with big grasping front appendages and a mouth surrounded by sliding bony plates that opened like a camera lens, to take bites of trilobytes and anything else that couldn't get away.
Simon Conway Morris, one of the main researchers at the Burgess shale site, has now written his own book, called The Crucible of Creation: The Burgess Shale and the Rise of Animals, and a fascinating one it is. (Oxford University Press, 1998.)
A lot has been learned about the Cambrian animals in the past decade, and Morris sums it up nicely. He also discourses elegantly on the differences between the hard Darwinists like Dawkins and Dennett on the one hand, and Gould with his theory of contingent evolution on the other. Gould, a Marxist, seems to require something more than the forces of natural selection to explain the results of evolution. His title is taken from the movie about how different life would have been without Jimmy Stewart's character. His thesis is that if evolutionary history were to be replayed, everything would come out quite differently.
Morris tries to be as polite and diplomatic as he can about saying Gould is all wrong, which is only fitting because Morris owes whatever fame he has outside the academic circles of paleontology to Gould's portrait of him in Wonderful Life. Nevertheless, he makes a strong and convincing case that ecological pressures cause certain niches to be occupied in certain ways, and that if evolution were to happen all over again, the result would be quite similar to what we have now, due to convergence caused by environmental pressures.
In fairness, Morris's conclusion has been strongly buttressed by recent findings about how molecular processes work in DNA, particularly with regard to the embryological development of particular body plans. Also, genetic analysis of the modern descendents of ancient animals has yielded a lot of information about which critters are related and how. Much of this exciting new stuff has happened since Gould's book was published, so that what looked ten years ago like phyla unrelated to anything living today now look like cousins and uncles of crabs and octopi. Gould's wrong guess didn't look quite so foolish back then as it does now.
There are lots of interesting pictures of the fossils, and a few color plates of artist's conceptions of life in the ancient seas. If you like this sort of stuff, you'll enjoy this one.