Boundless, December 7, 2000

Crumbling Icons


By Mark Hartwig

About 10 years ago, I came across a delightful article in the Italian journal, Rivista di Biologia. Titled "Be Cautious, Mr. Bates," the article challenged the Darwinian explanation of how the Viceroy butterfly came to look so much like the Monarch.

The most interesting part of the article was the way the authors chided biology professors for presenting speculative ideas as facts.

"Many generations have listened passively to these presentations," they noted. "We feel obligated, however, to warn our readers that these peaceful days are coming to an end and that we must prepare for strife."

Why? One reason was an organization called Students for Origins Research (SOR). "The members of this organization support creationism," the authors said, "but they are not naïve fundamentalists such as those in the Scopes case in 1925. These people have been educated (or coached) in the weaknesses of Darwinism. . . . They are preparing themselves for classroom debate."

They urged their readers to "avoid the usual practice of leading all discussions in such a way as to glorify Darwinian theory. With SOR students lurking in the class, frail scenarios will no longer be passively accepted."

As director of SOR at the time, I got a laugh out of the article. With a part-time volunteer staff of less than a dozen graduate and undergraduate students, and a scruffy tabloid journal that went out twice a year, we were hardly the kind of threat that the article implied.

The article was right about one thing, however: skepticism is on the rise in college biology classrooms. Books like Phillip Johnson's Defeating Darwinism by Opening Minds, William Dembski's Intelligent Design and Michael Behe's Darwin's Black Box have encouraged countless students to speak out. As a consequence, noted one observer, biology professors across the country "are finding students coming to class with mental defenses prepared so they will not be 'brainwashed' into accepting evolutionary theory."

That skepticism is about to get another boost from a new book by Berkeley-educated biologist Jonathan Wells. Titled Icons of Evolution: Science or Myth, this book shows that much of what introductory textbooks teach about evolution is demonstrably wrong. Worse yet, it documents the fact that evolutionary biologists have known it for years.

More than Misprints

Icons was born out of Jonathan Wells' own experience as a student.

"During my years as a physical science undergraduate and biology graduate student at the University of California, Berkeley, I believed almost everything I read in my textbooks," Wells recounts. "I knew that the books contained a few misprints and minor factual errors, and I was skeptical of philosophical claims that went beyond the evidence, but I thought that most of what I was being taught was substantially true."

But then he made a troubling discovery.

"As I was finishing my Ph.D. in cell and developmental biology," he writes, "I noticed that all of my textbooks dealing with evolutionary biology contained a blatant misrepresentation."

The texts contained drawings of embryos that supposedly provide compelling evidence of evolution.

But there was a problem, says Wells: "As an embryologist, I knew they were false."

Although he didn't stir up a ruckus, the discovery weighed on his mind. He began to notice that other illustrations were also wrong--important illustrations depicting evidence that Darwinists have long touted as "proof" of evolution. These pictures included such perennial favorites as Haeckel's embryos, peppered moths, the evolutionary "tree of life," Darwin's finches, the ape-to-man transition and others.

These images--and their accompanying evolutionary stories--are so widely used in textbooks that some have been called "icons of evolution." In his book, Wells examines 10 of the most common icons, showing that each of them seriously misrepresents the truth--either by presenting assumptions as observed facts, concealing raging scientific controversies or directly contradicting well-established scientific evidence.

Wrong From the Start

Among the most blatantly false icons are the embryo drawings that attracted Wells' attention. The pictures were drawn in the 1800s by German zoologist Ernst Haeckel (pronounced heckle), an enthusiastic supporter of Darwin's theory of evolution.

Haeckel proposed that the development of an organism's embryo replays the evolutionary history of that organism's species. He believed that as new organs or structures evolved, these features were tacked onto the end of an organism's embryonic development. As a result, we can virtually see the organism's evolutionary history in the embryo's development. At the beginning of its development, the embryo looks like its earliest ancestor. But as it develops and more recent features appear, it resembles later ancestors--until it finally reaches the point where it resembles its own species. Haeckel called this the biogenetic law.

On the basis of this law, he reasoned that the embryos of various organisms should look virtually identical early in development, but grow increasingly different over time--reflecting their evolutionary descent from a common ancestor. And when he made drawings of the embryos of several backboned animals, this is exactly what his drawings showed.

Unfortunately, Haeckel had more enthusiasm for his theory than for reality, and faked many of his drawings.

"In some cases," Wells says, "Haeckel used the same woodcut to print embryos that were supposedly from different classes [of animals]. In others, he doctored his drawings to make the embryos look more alike than they really were. His contemporaries repeatedly criticized him for these misrepresentations, and charges of fraud abounded in his lifetime."

In addition to doctoring his drawings, Haeckel also misrepresented the embryos' development. The stage of development that Haeckel called the "first" stage actually occurs about midway through the embryos' development. And although the embryos at this midway stage look faintly similar (if you squint hard and step back a bit), embryos at the earlier stages differ greatly.

Thus, instead of starting out virtually identical and then diverging, the embryos differ from the very beginning. About midway through development they converge to a vague similarity. Then they diverge again to their final forms.

Wells points out that biologists have known this for over a century. In 1894, for example, embryologist Adam Sedgwick rejected the idea that embryos start out similar and diverge over time, stating that this view is "not in accordance with the facts of development."

Sedgwick noted that he could distinguish between a chicken and a duck as early as the second day of development.

"Every embryologist knows that [early differences] exist and could bring forward innumerable instances of them," he said. "I need only say with regard to them that a species is distinct and distinguishable from its allies from the very earliest stages all through development" (emphasis in the original).

Sedgwick's observations are confirmed by modern embryology.

In spite of this, Wells found that Haeckel's drawings are almost universally touted in biology textbooks as powerful evidence for evolution. This is even the case in some advanced college texts written by eminent scientists.

Haeckel's drawings appear, for example, in the latest edition of Molecular Biology of the Cell, written by National Academy of Sciences president and distinguished cell biologist Bruce Alberts and his colleagues. The text states that "early developmental stages of animals whose adult forms appear radically different are often surprisingly similar," and that Darwinian evolution explains why "embryos of different species so often resemble each other in their early stages and, as they develop, seem sometimes to replay the steps of evolution."

Peppered Myth

Perhaps the biggest surprise in Wells' book is what he reveals about one of the Darwinism's most sacred icons: the peppered moth.

If you've taken a biology class in the last 30 years, you've probably seen photos of tree trunks with peppered moths resting on them. And you have no doubt been told that these moths are a prime example of "evolution in action," demonstrating the power of natural selection to change a creature's physical characteristics.

What you haven't been told, however, is that there is a problem with both the photos and the story behind them.

The story begins in the woodlands of England during the early 1800s. At that time the vast majority peppered moths were whitish with black speckles. Although some peppered moths were colored coal-black, they were very rare at that time.

As the industrial revolution took root during the 19th century, however, scientists noticed that moth populations near heavily-polluted cities had become mostly dark-colored. Scientists dubbed this shift industrial melanism and began to speculate about its cause.

In 1896, British biologist J.W. Tutt suggested that industrial melanism was caused by natural selection. He noted that in unpolluted woodlands, where tree trunks were covered with lichens, light-colored moths would be much better camouflaged than dark ones. As a result, predatory birds would spot and eat far more dark moths than light ones.

In industrialized areas, however, where airborne pollution had killed off the lichens and darkened the trees, the situation would be reversed. The dark moths would be better camouflaged, and the birds would catch more light-colored moths.

This eventually became the accepted view, and was apparently confirmed by studies conducted in the early 1950s by British biologist Bernard Kettlewell.

In these studies, Kettlewell marked several hundred moths of both colors and released them during the daytime onto tree trunks. For the next several nights he set out traps to recapture as many moths as possible. He then compared the percentage of light-colored moths he'd recaptured with the percentage of dark ones. This told him which type of moth survived better.

As Kettlewell expected, the recapture rate for dark-colored moths in polluted areas was about twice that for light-colored moths. In unpolluted areas the opposite was true. This was such ringing confirmation of natural selection that Kettlewell called his findings "Darwin's missing evidence." Other studies in the 1960s and 1970s seemed to back him up.

Of course, critics have long pointed out that changes in the relative size of moth populations tell us nothing about how such things as moths originated in the first place.

But in the 1980s another problem emerged. Researchers discovered that peppered moths almost never rest on tree trunks. Instead, they apparently rest on the undersides of small horizontal branches in the tree canopy.

By releasing moths onto tree trunks during the day, Kettlewell had created an artificial situation. "Peppered moths are night-fliers, and normally find resting places on trees before dawn," Wells says. When released during the day, in illumination bright enough for human eyes, such moths can be expected to choose their resting places as quickly as possible--often in the wrong place. "The moths that Kettlewell released in the daytime remained exposed, becoming easy prey for predatory birds."

This undermines the credibility of Kettlewell's studies, as well as later studies by others, which used dead specimens glued or pinned to tree trunks.

It also undermines the credibility of the photos displayed in so many textbooks. Since tree trunks are such an unusual resting place, Wells says, "pictures of peppered moths on tree trunks must be staged. Some are made using dead specimens that are glued or pinned to the trunk, while others use live specimens that are manually placed in desired positions. Since peppered moths are quite torpid in daylight, they remain where they are put."

These methods have also been used for television documentaries. One biologist admitted to a Washington Times reporter in 1999 that he had once glued dead specimens to a tree trunk for a TV documentary on peppered moths.

"Staged photos may have been reasonable when biologists thought they were simulating the normal resting places of peppered moths," Wells concedes. "By the late 1980s, however, the practice should have stopped."

Speak No Evil

The obvious question raised by these revelations is why? Why is this stuff still in textbooks? Why haven't scientists put up a fuss?

One reason is that many biologists simply don't know about the errors. "Most biologists work in fields far removed from evolutionary biology," Wells says. "Most of what they know about evolution, they learned from biology textbooks and the same magazine articles and television documentaries that are seen by the general public."

Other biologists, Wells says, "are aware of difficulties with a particular icon because it distorts the evidence in their own field. . . . But they may feel that this is just an isolated problem, especially when they are assured that Darwin's theory of evolution is supported by overwhelming evidence from other fields. If they believe in the fundamental correctness of Darwinian evolution, they may set aside their misgivings about the particular icon they know something about."

Some lapses, however, are more difficult to account for. Such is the case with Harvard paleontologist and science historian Stephen Jay Gould. In his writings, Gould has expressed an ongoing concern for the quality of science education in America. For example, when the Kansas state board of education voted in August 1999 to de-emphasize some of the more speculative aspects of evolution in the state's science education standards, Gould responded with a broadside published in Time.

"As patriotic Americans," Gould wrote, "we should cringe in embarrassment that, at the dawn of a new, technological millennium, a jurisdiction in our heartland has opted to suppress one of the greatest triumphs of human discovery."

Unfortunately, however, Gould's patriotism does not extend to confronting textbook publishers over such fraudulent material as Haeckel's embryos. Although Gould has known about Haeckel's fraud for over twenty years--he wrote and published a book on Haeckel's ideas in 1977--it wasn't until biochemist Michael Behe exposed the problem in the August 13, 1999, New York Times that Gould decided to speak out..

In the March 2000 issue of Natural History, Gould blasted textbooks writers for the "mindless recycling that has led to the persistence of these drawings in a large number, if not a majority, of modern textbooks." He also blamed "creationists" like Behe for capitalizing on the error.

But who's more at fault here: the mindless recyclers, or the scholar who kept silent until a "creationist" blew the whistle?

A Royal Pain

With the publication of Icons, prominent Darwinists are bracing for trouble. Speaking at the University of California, San Diego, Eugenie Scott, director of the National Center for Science Education, held up a copy of the book and told her listeners that every one of them should be aware of it.

"This book will be a royal pain in the fanny," she said.

Other Darwinists have made similar remarks.

That's really too bad. Rather than circling the wagons, shouldn't scientists and educators be more concerned about the facts? Wouldn't it be better to simply admit the errors--even if means conceding points to the "other side?"

You'd think so. But until that happens, classroom skepticism will only grow worse.

And those SOR students will have a heyday.

Mark Hartwig is science and worldview editor for Focus on the Family and a fellow of the Seattle-based Discovery Institute. For several years, he was director of Students for Origins Research and managing editor of the scholarly journal, Origins Research, now published as Origins and Design.