The Skeptics Society & Skeptic magazine

What Evolution Is

an excerpt from Why Darwin Matters, by Michael Shermer

Ever since Darwin, much has been written about what, exactly, evolution is. Ernst Mayr was arguably the greatest evolutionary theorist since Darwin. His extensive body of work and considerable longevity (when I phoned Ernst on his 100th birthday he was working on several articles and two more books) led to his authoritative history, theory, and synthesis of evolutionary thought. Mayr offers this technical definition: “Evolution is change in the adaptation and in the diversity of populations of organisms.” This reveals the dual nature of evolution. “It deals, so to speak, both with the ‘vertical’ phenomenon of adaptive change and with the ‘horizontal’ phenomenon of populations, incipient species, and new species.”¹ And I’ll never forget Mayr’s definition of a species, because I had to memorize it in my first course on evolutionary biology: “A species is a group of actually or potentially interbreeding natural populations reproductively isolated from other such populations.”²

Mayr outlines five general tenets of evolution, followed by five specific points about how natural selection works.³

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1. Evolution: Organisms change through time. Both the fossil record of life’s history, and nature today document and reveal this change.
2. Descent with modification: Evolution proceeds via branching through common descent. Offspring are similar to but not exact replicas of their parents. This produces the necessary variation to allow for adaptation to an ever-changing environment.
3. Gradualism: Change is slow, steady, and stately. Given enough time, evolution accounts for species change.
4. Multiplication of speciation: Evolution does not just produce new species; it produces an increasing number of new species.
5. Natural selection: The process of evolutionary change, co-discovered by Darwin and Alfred Russel Wallace, which operates in the following manner:

1. Populations tend to increase indefinitely in a geometric ratio: 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024…
2. In a natural environment, however, population numbers stabilize at a certain level.
3. Therefore, there must be a “struggle for existence” because not all of the organisms produced can survive.
4. There is variation in every species.
5. In the struggle for existence, those individuals with variations that are better adapted to the environment leave behind more offspring than individuals that are less well adapted. This is known as differential reproductive success.

This process of natural selection, when carried out over countless generations, gradually leads varieties of species to develop into new species. Within the natural selection paradigm, points A, B, and D are observations, C and E are inferences. C follows from A and B, and E follows from all three observations. In Darwin’s own words, here are his observations that led to his inference:

A struggle for existence inevitably follows from the high rate at which all organic beings tend to increase. Every being, which during its natural lifetime produces several eggs or seeds, must suffer destruction during some period of its life, and during some season or occasional year, otherwise, on the principle of geometrical increase, its numbers would quickly become so inordinately great that no country could support the product. Hence, as more individuals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of distinct species, or with the physical.⁴

And here is his inference:

It may be said that natural selection is daily and hourly scrutinizing, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life. We see nothing of these slow changes in progress, until the hand of time has marked the long lapses of ages, and then so imperfect is our view into long past geological ages, that we only see that the forms of life are now different from what they formerly were.⁵

Natural selection operates primarily at the local level. It is the process of organisms struggling to survive and reproduce in order to propagate their genes into the next generation. The Oxford evolutionary biologist Richard Dawkins succinctly defined evolution as “random mutation plus non-random cumulative selection.”⁶ Dawkins especially emphasizes the nonrandom element in the process in order to counter the myth that evolution is completely random, as in the creationists’ specious argument that evolution is the equivalent of a warehouse full of parts randomly assorting themselves into a jumbo jet. If evolution were truly random there would be no biological jumbo jets. Genetic mutations and the mixing of parental genes in offspring may be random, but the selection of genes through the survival of their hosts is anything but random. Out of this process of self-organized directional selection emerges complexity and diversity.

Natural selection is a description of a process, not a force. No one is “selecting” organisms for survival or extinction, in the benign sense of dog breeders selecting for desirable traits in show breeds, or in the malignant sense of Nazis selecting prisoners at Auschwitz-Birkenau. Natural selection, and thus evolution, is unconscious and non-prescient — it cannot look forward to anticipate what changes are going to be needed for survival. The evolutionary watchmaker is blind, says Dawkins, pace Paley. By way of example, once when my young daughter inquired about how evolution works, I used the polar bear as an example of a “transitional species” between land mammals and marine mammals, because although they are land mammals they spend so much time in the water that they have acquired many adaptations to an aquatic life. But this is not correct, because it implies that polar bears are on their way (in transition) to becoming marine mammals. They aren’t. Polar bears are not “becoming” anything. Polar bears are well adapted for their lifestyle. If global warming continues, perhaps polar bears will adapt to a full-time aquatic existence, or perhaps they will move south and become smaller brown bears, or perhaps they will go extinct. Who knows? No one.

References & Notes

1. Mayr, Ernst. 1988. Toward a New Philosophy of Biology. Cambridge, MA: Harvard University Press.
2. Ernst Mayr. 1957. “Species Concepts and Definitions,” in The Species Problem. Washington D.C.: Amer. Assoc. Adv. Sci. Publ. no. 50. Mayr offers this expanded definition: “A species consists of a group of populations which replace each other geographically or ecologically and of which the neighboring ones intergrade or hybridize wherever they are in contact or which are potentially capable of doing so (with one or more of the populations) in those cases where contact is prevented by geographical or ecological barriers.” See; Mayr, Ernst. 1976. Evolution and the Diversity of Life. Cambridge, MA: Harvard University Press.
3. Mayr, Ernst. 1982. The Growth of Biological Thought. Cambridge, MA: Harvard University Press.
4. Darwin, Charles. 1859. On the Origin of Species by Means of Natural Selection: or The Preservation of Favoured Races in the Struggle for Life. London: Charles Murray, p. 63.
5. Darwin, 1859. On the Origin of Species, p. 84.
6. Dawkins, Richard. 1976. The Selfish Gene. Oxford: Oxford University Press.

Dover, Pennsylvania:
The Battle for Our Children

a book review by Tim Callahan

When I said I thought it would be kind of good to learn more about evolution, some other kids started calling me Monkey Girl. ‘Cause they said God made them, but that I must’ve come from chimps.

The quote above is from the 14-year-old daughter of Tammy Kitzmiller, one of the chief plaintiffs in Kitzmiller vs. Dover, the court case that decisively stopped creationism from being taught as science in public schools in Pennsylvania — and, hopefully, the nation. It is particularly apt as the source of the title of this exceptional book, since some of the predominant character traits of fundamentalist creationists are a blatant and pervasive bullying nastiness, contempt for opposing views and those who express them, and general meanness of spirit. Perhaps we could pardon the ill-bred behavior of those claiming to be creatures of God in the quote above, since it is a trait not uncommon in teenagers. However, as Edward Humes reveals so powerfully in Monkey Girl, contemptuous bullying, name-calling, and character assassination were also the common tactics and behavior of the adult advocates of creationism in Dover, as well as those from around the nation who supported their ill-conceived assault on science.

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The attack on evolution was headed by two board members — Alan Bonsell and Bill Buckingham — both of whom wanted creationism taught in the district’s schools. Humes reveals that Buckingham is a retired crusading police officer who converted from Catholicism to evangelical Christianity at a time of personal crisis. He also attributes much of Buckingham’s bullying behavior on the board to mood swings he suffered as a result of addiction to the pain-killer OxyContin. At one point Buckingham stated: “Separation of Church and State is a myth. There is no separation.” And: “This country wasn’t founded on Muslim beliefs or evolution. This country was founded on Christianity, and our students should be taught as such.” As the board was beginning to formulate their creationist policy, Alan Bonsell told Bryan Rehm, a young science teacher at Dover High School, that the earth was less than 10,000 years old and that, “man didn’t evolve from monkeys.”

Further, Buckingham wanted the school district to buy 220 copies of the ID biology book Of Pandas and People. When Superintendent Richard Nilsen balked at purchasing the book, Buckingham revealed that he controlled enough board votes to block approval of the approved biology text and would not release them unless the board agreed to purchase Of Pandas and People. He told teachers and opposing board members, “If we don’t get our book, you don’t get yours.”

The board’s tactics became increasingly dictatorial from that point on. The new science curriculum was arbitrarily determined by the board with no input from the science faculty. When the possibility was raised at a public meeting that the science teachers might ask for legal representation from the district’s regular solicitor, the firm of Stock and Leader, Heather Geesay, another of the creationists on the board, said, “If they requested Stock and Leader, they should be fired. They agreed to the book and changes in curriculum.” This left teachers in a state of shock that a board member would dare suggest that teachers could be fired for seeking legal counsel. In addition, as Bertha Spahr, veteran biology teacher, reminded the board, Geesay was absolutely wrong: The teachers hadn’t had any input on the curriculum and had agreed to nothing. In the wake of the rancorous meeting, Casey Brown and her husband Jeff resigned from the board along with Noel Wenrich. The three were the only dissenters opposing the creationist majority. The board then appointed four new creationist members to fill the vacancies. Any applicant who had experience in education or did not voice support for ID was summarily rejected by the Board. When science teacher Brian Rehm applied, Buckingham insultingly asked him in public if he had ever been accused of child abuse or molestation. With a complete slate of creationists, the board now had no need either to compromise or, it would seem, to even treat their opponents with a modicum of civility.

The political climate at the outset of Dover did not favor the furtherance of teaching evolution. In the wake of Bush’s reelection at the end of 2004, a school board in Grantsburg, Wisconsin imposed a policy to criticize evolution. South Carolina, Tennessee, Michigan, Oklahoma, and Texas introduced similar, statewide, legislation. In California, a coalition of Christian schools sued the University of California for violating the Constitutional rights of students by refusing to give credit for creationist biology classes. Florida introduced legislation making it possible for students to sue professors for offending their religious beliefs. In Missouri, conservative legislator Cynthia Davis introduced legislation requiring biology textbooks used in the state to include a chapter on alternatives to evolution.

Against this political background, the plaintiffs in Dover went forward with their case in the fall of 2005. They included Brian and Christy Rehm, both teachers; Deborah Fenimore and Joel Leib, who had a son in middle school; Cynthia Sneath, parent; Steven Stough, middle-school teacher whose daughter was in eighth grade, Julie Smith, parent; Aralene “Barrie” Callahan, former school board member, along with her husband Frederick, Beth Eveland, parent; and Tammy Kitzmiller, whose daughter had been taunted with the epithet “Monkey Girl.”

In response to the lawsuit, the Dover board sought legal counsel from the Thomas More Law Center, whose mission statement reads:

Our ministry was inspired by the recognition that the issues of the cultural war being waged across America, issues such as abortion, pornography, school prayer, and the removal of the Ten Commandments from municipal and school buildings, are not being decided by elected legislatures, but by the courts. These court decisions, largely insulated from the democratic process, have been inordinately influenced by legal advocacy groups such as the American Civil Liberties Union (ACLU), which seek to systematically subvert the religious and moral foundations of our nation.

The Center is largely supported by Thomas Monaghan, the Domino Pizza magnate. Its lawyers helped draft legislation banning partial birth abortion in Michigan and all abortion in South Dakota, and advised Jeb Bush how to intervene in the Terri Schaivo case. It has also sued cash-strapped small cities for refusing to erect nativity scenes, and a Michigan school district for failing to allow an anti-homosexual speaker during “diversity week.” The Center also defended an anti-abortion web site that had posted names and addresses of doctors who performed abortions. Richard Thompson, chief legal counsel from the Thomas More Law Center decided on a strategy to make Bill Buckingham the fall guy, a loose cannon pushing an agenda not necessarily supported by the entire board. That Thompson was willing to sacrifice one of the board members was a forecast of impending disunity among the creationists. The Discovery Institute was so unenthusiastic about fighting the suit that Thompson said of them, “As soon as there’s a conflict, they will back away.” Indeed, the day the lawsuit was filed a press release from Discovery Institute appeared on their web site criticizing the Dover policy for its incoherence and dubious constitutionality.

In Dover itself public support for the board began to wane following the filing of the suit. Noel Wenrich, who had left the board along with the Browns, quipped that an overwhelming percentage of residents liked the ID policy, as long as it cost them nothing. “But not if taxes go up. Then it’s 30 percent.”

The defendants themselves also appeared to be abandoning their former bullying, no-compromise support for putting God into the science curriculum: When deposed prior to the trial, Buckingham, Bonsell, and Harkins denied ever mentioning creationism at any meeting, which contradicted witnesses and press reports. Board members also insisted they didn’t see ID as religion.

Further, the ID camp began to unravel. After the Discovery Institute pulled its support, chief ID defendant William Dembski refused to testify, as did his ID colleagues Stephen Meyer and John Angus Campbell, all of whom demanded to have their own personal attorneys to look after their interests in the trial. The Thomas More Law Center refused. As a result of the impasse, all three were out as expert witnesses for the defense. Eventually, Meyer and Campbell were reconciled and agreed to testify without having their own lawyers; but Dembski remained intractable and had to threaten to sue the Thomas More Center to be paid for more than 100 hours he had already spent on the case. At $200 an hour, this meant he was eventually paid more than $20,000 for not testifying.

From this point on the case went steadily downhill for the defense. Jon Buell, publisher of Pandas, tried to intervene in the case on the side of the defense. When cross-examined by plaintiffs’ attorney Eric Rothschild, Buell stated that he wanted to make sure that Pandas wasn’t represented as a creationist text. Rothschild confounded him by producing a letter Buell had written that stated: “Our commitment is to see the monopoly of naturalistic curriculum in the schools broken. Presently school curriculum reflects deep hostility to traditional Christian views and values, and indoctrinates students to this mind-set through subtle, but persuasive arguments.” The letter also said how important it was to stop schools from denying the notion that man was created in God’s image. Rothschild asked Buell how he could write such a letter in regards to the book and not have any idea that Pandas would be viewed as a creationist text. Buell didn’t answer, and the judge rejected his intervention.

Following that, the presentation of witnesses for the plaintiffs proved devastating and was followed by even more ruinous cross-examination of the defense witnesses, both the ID experts and the Dover school board members. Ken Miller, biologist and coauthor of the standard biology text known aas the Dragonfly Book, pointed out that exclusion of the supernatural from science was unavoidable and correct. Miller also pointed out that pseudogenes — random bits of DNA that don’t code for viable protein amino acid sequences and act merely as genetic place holders — are an effective proof of shared ancestry. Since pseudogenes are not subject to natural selection, they don’t change greatly. Hence, humans and chimpanzees share common pseudogenes. This is a test of evolution. Were chimps and humans independently designed, they would not likely share the same pseudogenes (or even have pseudogenes, for that matter); and if humans and chimps did not share the same pseudogenes, then evolution would be falsified.

Perhaps most harmful to the ID case was the testimony of Barbara Forrest, a professor from Louisiana who had been attacked in very personal and insulting terms by the Discovery Institute, and whom the Thomas More Law Center had fought to keep off the witness list. Forrest demonstrated convincingly that Of Pandas and People was originally a creationist text. In the 1986 draft Pandas said that creation means that life forms appear abruptly through the agency of an intelligent creator. In the 1993 draft, the words “creation” and “creator” were replaced respectively by “intelligent design” and “designer.” Forrest also dredged up quotes by Discovery Institute leading lights Phillip Johnson and William Dembski, illuminating the “wedge strategy” and showing the aim of Discovery was to teach creationism as a tool for spreading the Christian faith. Dembski, for example, was quoted as saying: “Intelligent Design should be viewed as a ground clearing operation that gets rid of intellectual rubbish that for generations has kept Christianity from receiving serious consideration.”

The cross examination of Michael Behe proved to be devastating to the scientific credibility of Intelligent Design. For example, Behe had said that a population of one billion bacteria would take 100 million generations to produce a novel protein feature through Darwinian evolution. At first, this seems so astronomical as to be an insurmountable barrier. However, Rothschild got Behe to admit that growing 10,000 generations of bacteria in a lab would take two years. Therefore, 100 million generations would take about 20,000 years, an eyeblink in geological time. Finally, Behe was forced to concede that there are about 10 quadrillion bacteria in one ton of soil — about 10 million times as many bacteria as Behe said would require 100 million generations to produce a novel protein.

Behe had also claimed that his theory of irreducible complexity was testable in a laboratory. Simply take a species of bacteria lacking a flagellum, place it in an environment that would favor mobile organisms, grow it for 10,000 generations — again, a mere two years — and see if a flagellum began to evolve. However, Behe had never done this. Rothschild asked him why he hadn’t performed this make or break experiment, one that could falsify either evolution or ID. Behe responded: “It would not be fruitful.”

So devastating was the trial to the defendants’ cause that four days after it ended, before Judge Jones had even handed down his verdict, the voters in Dover went to the polls and voted the entire board out of office. With predictable petulance, Pat Robertson said on the 700 Club in response: “I’d like to say to the good citizens of Dover, if there is a disaster in your area, don’t turn to God. You just rejected him from your city, and don’t wonder why he hasn’t helped you when problems begin.”

On December 20, 2005 Judge John E. Jones III rendered his verdict in Kitzmiller vs. Dover. He found that the board’s ID policy was unconstitutional, that the board had sought to inject religion into the classroom, while undermining the teaching of science, and that intelligent design was a religious proposition, not science. He further characterized the Board’s policy as “breathtaking inanity.” For carrying out his duty of enforcing the law of the land, Judge Jones was subsequently vilified by the Discovery Institute, conservative commentator Bill O’Reilly, and Ann Coulter, the latter of whom wrote: “They didn’t win on science, persuasion, or the evidence. They won the way liberals always win: by finding a court to hand them everything on a silver platter.”

Before the trial, Judge Jones, a Bush-appointed moderate Republican who once led an unsuccessful attempt to privatize Pennsylvania’s state-owned liquor stores, was characterized by the Discovery Institute as one of their own. On William Dembski’s web site, after listing Jones’ conservative credentials, a pretrial posting confidently stated: “Unless Judge Jones wants to cut his career off at the knees he isn’t going to rule against the wishes of his political allies. Of course, the ACLU will appeal. This won’t be over until it gets to the Supreme Court. But now we own that too.” It would appear that, in direct contradiction to what Coulter said of the trial, it was the religious right that expected a friendly court to hand them victory on a silver platter. Once Jones’ ruling went against them, Discovery Institute labeled him a typically liberal “activist” judge.

While the trial in Dover will not bring about the demise of either creationism or ID, it may have set enough of a precedent to keep ID out of the public schools, at least for awhile. Monkey Girl is a fascinatingly detailed record of the creationist war on science, one that links national movements to their impacts on the lives of individuals and the education of our children.