ICONS OF EVOLUTION? WHY MUCH OF WHAT JONATHAN WELLS WRITES ABOUT EVOLUTION IS WRONG ALAN D. GISHLICK NATIONAL CENTER FOR SCIENCE EDUCATION INTRODUCTION that are commonly used to help to teach evolu- tion. Wells calls these the “icons,” and brands THE PARADIGM OF EVOLUTION them as false, out of date, and misleading. volution is the unifying paradigm, the Wells then evaluates ten “widely used” high organizing principle of biology. school and college biology textbooks for seven EParadigms are accepted for their overall of these “icons” with a grading scheme that he explanatory power, their “best fit” with all the constructed. Based on this, he claims that their available data in their fields. A paradigm func- treatments of these icons are so rife with inac- tions as the glue that holds an entire discipline curacies, out-of-date information, and down- together, connecting disparate subfields and right falsehoods that their discussions of the relating them to one another. A paradigm is icons should be discarded, supplemented, or also important because it fosters a research amended with “warning labels” (which he pro- program, creating a series of questions that vides). give researchers new directions to explore in According to Wells, the “icons” are the order to better understand the phenomena Miller-Urey experiment, Darwin’s tree of life, being studied. For example, the unifying para- the homology of the vertebrate limbs, digm of geology is plate tectonics; although Haeckel’s embryos, Archaeopteryx, the pep- not all geologists work on it, it connects the pered moths, and “Darwin’s” finches. entire field and organizes the various disci- (Although he discusses three other “icons” — plines of geology, providing them with their four-winged fruit flies, horse evolution, and research programs. A paradigm does not stand human evolution — he does not evaluate text- or fall on a single piece of evidence; rather, it books’ treatments of them.) Wells is right is justified by its success in overall explanato- about at least one thing: these seven examples ry power and the fostering of research ques- do appear in nearly all biology textbooks. Yet tions. A paradigm is important for the ques- no textbook presents the “icons” as a list of our tions it leads to, rather than the answers it “best evidence” for evolution, as Wells gives. Therefore, the health of a scientific field implies. The “icons” that Wells singles out are is based on how well its central theory explains discussed in different parts of the textbooks for all the available data and how many new different pedagogical reasons. The Miller- research directions it is spawning. By these Urey experiment isn’t considered “evidence criteria, evolution is a very healthy paradigm for evolution”; it is considered part of the for the field of biology. experimental research about the origin of life In his book Icons of Evolution (2000), and is discussed in chapters and sections on the Jonathan Wells attempts to overthrow the par- “history of life.” Likewise, Darwin’s finches adigm of evolution by attacking how we teach are used as examples of an evolutionary it. In this book, Wells identifies ten examples process (natural selection), not as evidence for 1 Icons of Evolution? Why Much of What Jonathan Wells Writes about Evolution is Wrong Alan D. Gishlick, National Center for Science Education evolution. Archaeopteryx is frequently pre- 2000: xii). This is a serious charge; to support sented in discussions of the origin of birds, not it demands the highest level of scholarship on as evidence for evolution itself. Finally, text- the part of the author. books do not present a single “tree of life”; Does Wells display this level of scholar- rather, they present numerous topic-specific ship? Is Wells right? Are the “icons” out-of- phylogenetic trees to show how relevant date and in need of removal? And more impor- organisms are related. Wells’s entire discus- tantly, is there something wrong with the theo- sion assumes that the evidence for evolution is ry of evolution? a list of facts stored somewhere, rather than the In the following sections, each textbook predictive value of the theory in explaining the “icon” is reexamined in light of Wells’s criti- patterns of the past and present biological cism. The textbooks covered by Wells are world. examined as well, along with the grading cri- TEXTBOOK “ICONS”: teria (given in the appendix of Icons [Wells, WHY DO WE HAVE THEM? 2000] and on the Discovery Institute’s web- Paradigms and all their components are not site) that he used to assess their accuracy. What necessarily simple. To understand the depth of was found is that although the textbooks could any scientific field fully requires many years always benefit from improvement, they do not of study. It is the goal of elementary and sec- mislead, much less “systematically misin- ondary education to give students a basic form,” students about the theory of biological understanding of the “world as we know it,” evolution or the evidence for it. Further, the which includes teaching students the para- grading criteria Wells applied are vague and at digms of a number of fields of science. In times appear to have been manipulated to give order to do this, teaching examples must be poor grades. Many of the grades given are not found. It is this need to find simple, easy-to- in agreement with the stated criteria or an explain, dynamic, and visual examples to accurate reading of the evaluated text. Beyond introduce a complex topic to students that has that, Icons of Evolution offers little in the way led to the common use of a few examples — of suggestions for improvement of, or changes the “icons.” Yet, with our knowledge of the in, the standard biology curriculum. When natural world expanding at near-exponential Wells says that textbooks are in need of cor- rates, the volume of new information facing a rection, he apparently means the removal of textbook writer is daunting. The aim of a text- the subject of evolution entirely or the teaching book is not necessarily to report the “state of of “evidence against” evolution, rather than the art” as much as it is to offer an introduction the fixing of some minor errors in the presen- to the basic principles and ideas of a certain tation of the putative “icons.” This makes field. Therefore, it should not be surprising Icons of Evolution useful at most for those that introductory textbooks are frequently sim- with a certain political and religious agenda, plified and may be somewhat out-of-date. In but of little value to educators. Icons of Evolution, however, Wells makes an even stronger accusation. Wells says: References “Students and the public are being systemati- Wells, J. 2000. Icons of evolution: science or myth?: cally misinformed about the evidence for evo- why much of what we teach about evolution is wrong. lution” through biology textbooks (Wells, Regnery, Washington DC, 338p. 2 Icons of Evolution? Why Much of What Jonathan Wells Writes about Evolution is Wrong Alan D. Gishlick, National Center for Science Education THE MILLER-UREY how the early atmosphere was probably differ- EXPERIMENT ent from the atmosphere hypothesized in the original experiment. Wells then claims that the THE EXPERIMENT ITSELF actual atmosphere of the early earth makes the he understanding of the origin of life Miller–Urey type of chemical synthesis was largely speculative until the 1920s, impossible, and asserts that the experiment Twhen Oparin and Haldane, working does not work when an updated atmosphere is independently, proposed a theoretical model used. Therefore, textbooks should either dis- for “chemical evolution.” The Oparin– cuss the experiment as an historically interest- Haldane model suggested that under the ing yet flawed exercise, or not discuss it at all. strongly reducing conditions theorized to have Wells concludes by saying that textbooks been present in the atmosphere of the early should replace their discussions of the Miller– earth (between 4.0 and 3.5 billion years ago), Urey experiment with an “extensive discus- inorganic molecules would spontaneously sion” of all the problems facing research into form organic molecules (simple sugars and the origin of life. amino acids). In 1953, Stanley Miller, along These allegations might seem serious; how- with his graduate advisor Harold Urey, tested ever, Wells’s knowledge of prebiotic chemistry this hypothesis by constructing an apparatus is seriously flawed. First, Wells’s claim that that simulated the Oparin-Haldane “early researchers are ignoring the new atmospheric earth.” When a gas mixture based on predic- data, and that experiments like the Miller– tions of the early atmosphere was heated and Urey experiment fail when the atmospheric given an electrical charge, organic compounds composition reflects current theories, is simply were formed (Miller, 1953; Miller and Urey, false. The current literature shows that scien- 1959). Thus, the Miller-Urey experiment tists working on the origin and early evolution demonstrated how some biological molecules, of life are well aware of the current theories of such as simple amino acids, could have arisen the earth’s early atmosphere and have found abiotically, that is through non-biological that the revisions have little effect on the processes, under conditions thought to be sim- results of various experiments in biochemical ilar to those of the early earth. This experiment synthesis. Despite Wells’s claims to the con- provided the structure for later research into trary, new experiments since the Miller–Urey the origin of life. Despite many revisions and ones have achieved similar results using vari- additions, the Oparin–Haldane scenario ous corrected atmospheric compositions remains part of the model in use today. The (Figure 1; Rode, 1999; Hanic et al., 2000).