World and I, February 1, 2001
Icons of Evolution: Science or Myth? Why Much of What We Teach About Evolution
Publisher:Washington, D.C.: Regnery Publishing, 2000
When I first picked up Icons of Evolution by Jonathan Wells, my mind formed an image of a lonely priest of science trudging to the cathedral door with a few reforms and a hammer. His mission is iconoclastic. He intends to smash the holiest relics of evolutionary theory, the examples used in textbooks or the popular press to such a degree that they have become "icons." He attacks in turn the origin of life's building blocks, the evolutionary tree, homology of vertebrate limbs, Haeckel's embryos, origin of birds, peppered moths, Darwin's finches, mutation, horse evolution, and apes to humans. He concludes that science in general is no better than mythology, and our biology textbooks are so flawed that they should carry a warning label like cheap cigarettes. The Lord may be subtle, but Wells is not! He is crusading to take the teaching of evolution out of schools, although he might be willing to settle for just not teaching it very seriously.
Wells, who has a Ph.D. in religious studies from Yale and another in molecular and cell biology from Berkeley, is presently a senior fellow at Discovery Institute's Center for Renewal of Science and Culture. He represents the viewpoint that living creatures may have changed through time but only according to a preconceived plan (intelligent design). This is a flexible position, permitting its adherents to accept most of the evidence for evolution but still deny the importance of natural selection.
Politics aside, Wells is a good writer who lays out his arguments clearly and is factually accurate. As a practicing scientist, I was fascinated by his descriptions of scientific shenanigans. We should be reminded that science is practiced by people who share humanity's flaws, just like politicians, lawyers, doctors, and priests. We all promote viewpoints in which we have a vested interest as unbiased. So we get some mistakes and a little bad science! The world goes on. Or does it? Wells claims that scientists conspire to support philosophy that competes with religion. In fact, he suggests that scientists are more concerned with philosophy and moral values than theologians are. The trouble is that he gives a clear impression that their philosophy is dangerous. Materialism is the word he uses to describe Darwin's motivation for writing The Origin of Species.
Wells takes his hammer to the most basic of questions: Where does life come from? The shattered icon is the famous Miller-Urey experiment, in which amino acids that are building blocks for proteins and DNA appeared spontaneously when certain gases were subjected to an electric spark meant to simulate lightning. It's the gas mixture that has Wells up in arms. It was supposed to resemble the early atmosphere, but some scientists now think that atmosphere contained significant oxygen, an element that might negate the Miller-Urey process. The true significance of their experiment is how easily many of the complex building blocks of life can be generated by processes that should happen somewhere in the natural world. I doubt if we know much for certain about early earth atmospheres. I am a bit puzzled why this chapter was included, as the origin of life does not seem to be an evolutionary question. It's obvious that for Wells, the big origin questions are more upsetting than natural selection and Darwin.
The next target for the wrecking ball is a big edifice, the tree of life. Unfortunately, he tries to demolish it with a firecracker. Needless to say, the damage is superficial. Part of the cleverness of this book is the skillful way Wells turns the scientists' hype and hyperbole toward his own ends. He is quick to emphasize the description of Cambrian diversification as an "explosion" taking place in a few tens of millions of years and to argue that this does not give enough time for Darwinian evolution. He also points out that some organisms do not fit neatly into living phyla, so diversity was higher in the Cambrian, when we first see most phyla. According to Wells and some paleontologists, this turns the evolutionary pyramid upside down, causing Darwinism to totter.
Actually, the fossil record and theory make a good fit. The higher a unit of classification is placed in the hierarchy, the earlier it is supposed to have appeared in time. Phyla are higher taxonomic levels and might be expected to appear before modern classes and orders. That is exactly what we see. We might also expect a few experiments that finally failed. They were not that different from their neighbors but lacked the marker characters of any modern phylum and so get to be phyla of their own. This inflates diversity if that is how we count it, but if we could go back in a time machine, the most impressive thing would be how uniform life was in the Cambrian.
Wells does not claim that there were any fish in the Cambrian seas, let alone fishermen. In fact, he accepts the fossil record and geological time as presented by the geologists. There has been a lot of extinction at different times. Probably 95 percent of all the species that have ever lived are now extinct, but this doesn't mean that at any time in the past there was nearly twenty times the biodiversity there is today. Many extinctions were followed by the appearance of new taxa. Either there is a Creator who operates according to the old motto "if at first you don't succeed, try again" or there is some mechanism, like evolution, to replace lost diversity.
Wells combines an attack on the modern concept of homology (similarity due to common descent) with one on the embryological support for evolution. The attack on homology is especially vague. I'm sure that he must have some learned source for his statement that "Owen and Darwin regarded the archetype as a prototypical organism," but I don't have a clue what he means. Does he suggest that they thought there was an actual prototype which was modified to produce the flippers of a porpoise and the wings of a bat? That certainly has an evolutionary ring to it! In any case, he admits the evidence but denies its utility because homology is now a phylogenetic concept. If homologies are used to create phylogenies, and phylogenies test the reality of homologies, the system rotates. This is usually considered a bad way to think and might be damaging if the only tests for homology were so confined.
How should we predict the appearance of morphological features across species if evolution is a correct explanation for biodiversity? We would expect many different patterns based on modifications of a few basic plans, and that is precisely what we see. This is not an ism. This is common sense! Our alternatives seem to consist of Plato, Aristotle, and the mind of God. As the latter is unknowable, it might encompass anything. I think Wells missed this icon because he simply couldn't see his target.
Many of his remarks about birds as dinosaurs were enjoyable. His description of the Florida meeting on bird origins, which I attended, did fit some of his suggested cartoon captions: "Cladistic mob tars and feathers defenseless dinosaur" or "Turkey sandwich proves birds evolved from Triceratops." There is plenty of humor in the bird-dinosaur debate, but the important thing is that it is a debate and neither side has been permitted to suppress the other, no matter how much it might want to. That is good science, even if some things that get by are laughable.
The discussion of Archaeopteryx is more to the point. What do we mean by a transitional species? Are fossils only informative if they are direct ancestors? This would certainly limit their value, as it would require awfully good luck and might be hard to prove even if we were successful. Fortunately, it is not necessary as evidence for evolution. When we compare birds to other animals, there are many features known only in birds or in animals so different that they can't be confused (like the turtle's beak).
If animals were created, we might expect these features to continue back in time to their creation, but evolution would predict that defining features would disappear progressively as we sampled older and older rocks. Because our definition of what a bird is depends on these features, the fossils become less and less birdlike until we are forced to decide how many must remain before we cease to claim that we have a bird. At any earlier time, most individuals should differ from later forms by more closely resembling other animals. In other words, if you wanted to know how some ancestor dressed but lacked a photo of that person, you could settle for an old photo of anybody who shared the appropriate social attributes; as long as time and place were correct, you could make a fair estimation.
As we go back in time, evolution predicts that birds will become less "birdy." Feathers are obvious bird features, but a toothless horny bill, saddle-shaped vertebrae, and short tail work just as well. Eighty million years ago, Ichthyornis lacks the toothless bill on the lower jaw and part of the upper, although there is one on the front of the upper jaw. The saddle-shaped vertebrae are also gone, but it may still be a bird on the basis of the tail and feathers. By 140 million years ago, Archaeopteryx lacks the horny bill altogether and has a long tail. We are left with the feathers to demonstrate that it is a bird. Not a bad icon if the criterion is how well it supports evolution.
The same is true for the horse story. It does not matter much whether the evolutionary tree is bushy or not. The fact that as we go back in time we lose the features that distinguish modern horses is not questioned by Wells and fits evolutionary predictions, including tooth- crown height and the number of toes on the feet. Wells, or anyone else, will look in vain for one-toed horses with high-crowned teeth among the thousands of Oligocene fossils in museums. Thirty-three million years later, we can't find anything else. Wells can and does complain about the philosophy of scientists, but it won't change the fact that the two fossil examples still seem largely unmarred insofar as support for evolution is concerned.
While we are talking about fossils, what about the human story? What are australopithecines if not the bones of primitive humans? Why do we not find modern humans with them? Wells seems to accept the fossil evidence at face value and contents himself with pointing out the confusion over Neanderthals when they were first discovered, or how reconstructions vary over how human an australopithecine might have looked in life. He seems genuinely uncomfortable about what we should do with these lowbrow cousins and microcephalic uncles attached to our family tree. Should they be locked away in the cellar so schoolchildren will not see them? He hits his stride with Piltdown Man, a deliberate fake, but his attempt to resolve the human story into petty wrangling over a few old bones cannot change the broad outline of human evolution, which remains intact using evidence that he allows.
Peppered moths, Darwin's finches, and the four-winged fruit fly are icons rooted in modern experimental biology. They examine the origins of variability through mutation and the strength of natural selection in changing morphology. The fruit fly is a laboratory example and simply shows the amount of gross change that can accompany mutation. I don't think that anyone thinks that it will escape the lab and spawn a race of four-winged monsters, as might happen in a horror movie. I don't know what upsets Wells with this example, except that he makes a distinction between biochemical evolution, where he seems to accept good old natural selection, and morphological evolution, where he does not.
The moths and finches are morphological examples, and Wells goes after them with whatever weapons are at his disposal. His best are always the flaws of the scientists themselves. We can watch Kettlewell as he tries to design experiments evaluating selection under natural conditions, then failing because his need to observe changes the behavior of his subjects. When he turns them loose he can show strong selection, but the proximate cause eludes him and still seems to be a mystery. What seems clear is that there are more dark moths during times of industrial pollution and fewer when the air is clean. Wells hints that the pollution itself might be the cause. I'm not sure where that reasoning takes us. If it means that darker moths survive to reproduce in polluted regions, it is still selection, but if the moths just turn black when exposed to pollution it means something else. I think that Wells implies the latter, but I'm not sure. After all, he is a scientist and knows how to be cryptic when uncertain of his facts.
He doesn't seem to question any basic principles surrounding Darwin's finches except to show that most things we know about them were discovered after Darwin. They seem to all derive from a smaller number of species (one?) that diverged morphologically but not so much genetically to prevent several from beginning to hybridize. Depending on local seed availability, natural selection changes the overall distribution of a morphological character, bill thickness, and when the selective pressure is reversed, the bill thickness dutifully returns to its former state. In some ways, this demonstrates exactly what the pepper moths were supposed to show. Wells demonstrates how the story about Darwin's finches has changed with new data, but it does not damage the icon. It's more like he cleaned it up and added a little polish.
Chapter 12, "Science or Myth," takes its recipes from one of the oldest cookbooks known to man. First you demonstrate that your opposition is truly bad and deserves to be cooked. Scientists aren't misguided or careless; they are criminals bent on misleading innocent children. Something has to be done to protect the public from these false priests. You have to take away funding for evolutionary science, and then you must suppress their publications.
Wells suggests that we ensure that our taxes or donations are not used to support the evils of Darwinism. He is careful to suggest that this doesn't apply to science as a whole but only to science that is misguided. As he does not give us a list of good sciences, some suspicion must linger around any discipline. Certainly most of geology and astronomy and quite a lot of physics would disappear if the creationists' view that the earth is only a few thousands of years old were true. I am happy to report that Wells does not take such an extreme view, accepting geologic time and the distribution of extinct species as they are generally presented in textbooks. He overlooks the fact that the errors he reports were discovered by scientists and that the process is self-correcting. The fact that the so-called frauds are mostly adjustments over time to an evolving system of scientific thought escapes Wells, who would rather find some evil to contrast with his version of good.
Icons of Evolution is full of sound and fury, but as far as attacking examples of evolution, it does not signify much. I had expected to enter the scientific cathedral and find the shards of its holy relics scattered across the floor, but mostly they hung in their usual place, some in need of polish and maybe one or two put away until their miraculous nature is better substantiated. Wells may see himself as Martin Luther nailing his reforms to the church door, but at the end of the book his call for political action sounds a lot like an attempt to suppress philosophical viewpoints that disagree with his own. He seems to think that science is not adequately spiritual and, as a result, less moral and caring than it should or could be.
He is obsessed with the impact of evolutionary thought on man's place in the cosmos and how it spawns a godless, materialistic philosophy. He implies that evolutionary theory was created with that purpose. I was amazed at his efforts to impose political definitions on dead people. Was Darwin a materialist? I doubt that he even thought in those terms, and if he did, what has that to do with his science? Science is by definition engaged in natural explanations. It cannot deal with the supernatural. Mixing the two has invariably resulted in bad science and corrupted religion. I think that this is especially true in education. Does it make sense to deny students the best arguments concerning concepts and examples that they are going to have to deal with for the rest of their lives? Or should we hope that our children will join holy orders so their lives and thoughts can be perpetually controlled by those who know better what is right and reasonable versus what is wrong and false? If you want the latter, Wells gives instructions on how to put warning labels on books and get politicians to suppress what you do not like.
If you think that evolutionary theory is a threat to civilization, you will enjoy this book in its entirety. If you are simply interested in the guilty pleasure of seeing scientists behaving badly, there is a lot here for you, too. The examples are well drawn and documented. If Wells made a technical error, I missed it.
I think he is to be commended for his care and, on balance, the book provides an interesting insight into how science actually works and why it sometimes fails. Anyone might usefully read it on that basis. God has been carefully left out, and the authority figure is usually Steven J. Gould, so the book is not overtly a religious tract. It might be billed as an attack on evolution but actually fails on that account, leaving the careful reader with the impression that the author has accepted all the basic features of descent with modification and is now only seeking direction. If that is the case, then the call to arms in the last chapter seems out of place, except to placate what Wells may have thought was the book's natural constituency.
Larry D. Martin is professor of ecology and evolutionary biology and curator of vertebrate paleontology at the University of Kansas. He is the author of some three hundred scientific papers and two books dealing with evolution and the fossil record.
Copyright 2001 Larry D. Martin. All rights reserved. International
File Date: 2.27.01