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(More customer reviews)In Icons of Evolution, Jonathan Wells explores a handful of classical examples used in introductory biology textbooks that illustrate aspects of evolution, textbooks generally aimed at the high school level. These "icons" are primarily attacked on the basis that they are inaccurate, leaving out important details, or downright false; however, these critiques are based primarily on appeals to authority and Wells does little to address the abundance of research beyond these iconic examples. Many of his characterizations of the primary scientific literature are also questionable. In general, he seems to over state the importance and implications of his icons to erect a straw man which he can easily attack.
The manner in which Wells addresses some of the icons seems especially misguided. His discussion of molecular clocks and Darwin's "Tree of Life" centers almost completely on isolated problems/disagreements and raises the specter of the Cambrian "explosion" where questions undoubtedly remain; however, little thought is given to the successes and positive contributions of these molecular techniques and the numerous parallel lines of evidence that support the tree of life. He paints an utterly pessimistic picture of molecular phylogenetics, likely leaving most readers with the perception that the methodology is flawed and in a crisis and that the data produced is wholly invalid. In reality, quite the contrary is true; phylogenies based on molecular data are becoming increasingly valuable and typically agree with phylogenies based on other data sets (such as fossils or morphology.) The evidence in support of common descent, however, is far deeper than Wells' cursory critiques address. When one wades into the true wealth of evidence and looks at the genetic similarities between species despite protein and DNA redundancy, identical insertion locations of endogenous retroviruses, and shared transposons, introns, and pseudogenes (the L-gulono-gamma-lactone oxidase gene is my personal favorite), it becomes clear that Icons of Evolution plays in the shallow wading pool of science and rarely dips its feet into the deeper "big-kids" pool. What is truly significant about these other lines of data is their congruency without exception; we do not see homologous pseudogenes or retroviral insertions where not predicted by common descent. While it is certainly true that grey areas remain and there are numerous unanswered questions, in order for Wells to truly advance his thesis that the iconic "Tree of Life" is unsubstantiated, as well as his other icons, he must address these independent lines of evidence and not just focus on superficial uncertainties.
The "Tree of Life" is but one of the "icons" explored in this book and many others are equally disingenuous. Haeckel's embryos are perhaps one of the better known icons. It is true that Haeckel fudged his drawings to show that animal embryos appeared more similar than they really were and his Biogenetic law was wrong. Wells does not stop his criticism there, though; he goes on to equate Haeckel's dishonest drawings and discredited theory with evolution in general. He spends most of the chapter obfuscating the matter further without ever addressing the reality of the issue: vertebrate embryos really are similar. This is exemplified by the fact that many textbooks now use photographs to compare embryological development. Furthermore, Wells' contentions with the Galapagos finches and peppered moth examples seem obtuse. The changes seen in these animals was not mere acclimation, such as sheep growing thicker wool in colder climates or humans adjusting to lower oxygen concentrations at high altitudes; what was observed in these cases was a change in the frequencies of discrete genetic traits, the evolutionary consequences of natural selection. Essentially, we can document the development of new genes and functions, witness changes in populations as they adapt to their environment, and find closely related species that seem to have arisen through gradual change, but Wells refuses to put the pieces together, maintaining that each step is isolated and not evolution. While neither of Wells' "icons" ideally exhibits every nuance of speciation, it must be remembered that they are used in the context of introductory textbooks. Many other examples can be found that perhaps elucidate different stages of evolution better (e.g., the nylonase enzyme, pentachlorophenol (PCP) metabolism, ring-species) but few would be appropriate for this level of science and would likely complicate the matter needlessly. The subtitle of this book (Why Much of What We Teach...) is quite significant to the conclusions that one draws from the content; if one approaches this text as addressing pedagogy and not the legitimacy of evolution, it can be quite insightful. However, this book does an abysmal job of critiquing the legitimacy of the Theory of Evolution as a whole.
Icons of Evolution is very well written and an easy read, echoing the comments of many others. Although inaccurate at times, it provides an insight into many of the arguments and areas of contention that Intelligent Design advocates have with evolution and serves as a good primer to the debate occurring in contemporary society. However, like any other isolated book, Icons of Evolution should not be considered authoritative. For anyone truly interested in this topic, I encourage you to read a variety of sources and authors, search databases for relevant research papers, and look into the primary scientific literature that authors cite. There is a wealth of information available for those wishing to remain intellectually honest.
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Everything you were taught about evolution is wrong.
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