Laelaps

Book Review: Why Evolution is True

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If you have never heard of sexual selection, if “evo-devo” sounds like the name of an 80’s new wave band, if you believe in evolution but don’t understand it, Jerry Coyne’s forthcoming book Why Evolution is True isn’t a bad place to kick off your intellectual journey. There is no one book that can encompass everything that is important to understand about evolution, but Why Evolution is True makes an admirable attempt at surveying the intertwining lines of evidence scientists follow to determine how life came to be as it is. Indeed, Coyne’s book follows in the long tradition of popular books that have plainly expounded upon the basics of evolution by natural selection, working as a primer and a road-map for those with an interest but not much background. Paired with Donald Prothero’s fossil-oriented survey, Evolution: What the Fossils Say and Why it Matters, Coyne’s book can be a useful resource to the general reader.

If you are already familiar with the basics of evolution, though, the book does not present much that is novel, and it might be better to pass it up to slog through familiar explanations of evolution involving Tiktaalik, widowbirds, bacterial resistance, etc. Worse, the book is not only a little bland, but it is pockmarked by a series of small errors and failures to convincingly marshal the available evidence in favor of evolution. For the purposes of this review, I will stick to the areas in which I have experience; the fossil record and the history of science.

First, the fossil record. Early in the chapter, “Written in the Rocks,” Coyne states that in order for a fossil to be formed, the remains of an animal must find their way into water and become buried, after which they are mineralized over time. Fossils can form this way, but it is not the only way that fossils can form, nor are all fossils bones. Fossils may be bones, footprints, body impressions, coprolites, feathers, armor, teeth, insects in amber, burrows, shells, etc. Generally, they are the preserved traces of ancient life, and preservation will differ in different environments. An insect can be stuck in sap which turns to amber, a mammal could die in a hollow treetrunk filled with sediment and debris, or a nesting dinosaur could be buried in sand or mud. There is no one way to make a fossil. Perhaps this is nitpicking, but I think that Coyne’s treatment of fossil formation leaves far too much out. This is a recurring theme in the chapter.

Rather than chronologically surveying the whole of vertebrate evolution (the traditional method, exemplified by Prothero’s book, Colbert’s Evolution of the Vertebrates, and Richard Fortey’s Life), Coyne selects a handful of transitions to make his case. In a move that annoyed me throughout the book, Coyne calls these fossils “Missing Links.” I wanted to strike the phrase out every time I saw it. The term “missing link” is associated with the Great Chain of Being, or a ranked order of nature from lower (inferior) to higher (superior). Even though this idea has fallen out of fashion as an organizing concept for life and the pattern of evolution, it still remains in our explanations and illustrations. On page 50, for instance, a phylogeny of whales is provided to illustrate whale evolution. It is a branching diagram, that is true, but what is meant to catch the eye are the illustrations showing a terrestrial creature on the bottom and a baleen whale on the top, a straight-line progression from one point to another. We complain when people say they think evolution is goal-oriented, but in our illustrations (which can be more influential than the text), we are still supporting “Chain thinking.”

The first group of transitional forms to be covered are early tetrapods, in the subsection “Onto the Land: From Fish to Amphibians.” Tiktaalik is the star of this section, to the detriment of other genera. The story of Tiktaalik is a good one, particularly how a search was mounted to test an evolutionary prediction, but not enough information is provided about the evolutionary bookends on either side of the famous fishapod. Coyne says that there were terrestrial tetrapods on the one side and fish on the other, but essentially no details are given about them (in an illustration, Eusthenopteron is chosen as the fish and Acanthostega is chosen as the tetrapod, with Tiktaalik in between).

As pointed out in a new review by Coates et al. on early tetrapods, though, there was not only a diversity of early tetrapods, but two radiations of animals important to understanding the evolution of the group. Likewise, limbs evolved in the water and were then used to move about on land, but Coyne repeats the standard trope about the evolution of limbs and the “invasion of the land.” I can’t hold him accountable for a review published after his book was printed, of course, but the information in the Coates et al review is not new, and there have been other reviews of early tetrapods (like Jennifer Clack’s Gaining Ground) that could have helped flesh out the story.

Next up is the evolution of birds, which leads to something of a contradiction. Coyne starts off by stating that “if you think about it a bit, it’s not so hard to come up with intermediate stages in the evolution of flight, stages that might have been useful to their possessors. Gliding is the first obvious step. And gliding had evolved independently many times: in placental mammals, marsupials, and even lizards.” For the evolution of birds, this would mean a “trees down” origin for flight. Later in the chapter, though, Coyne states that the “ground up” scenario is more likely, which makes the opening statements of the section peculiar.

Nevertheless, this section is like the last in that sparingly few feathered dinosaurs and early birds are mentioned. Archaeopteryx is the star, but Coyne makes a mistake when he states “After the discovery of Archaeopteryx, no other reptile-bird intermediates were found for many years, leaving a gaping hole between modern birds and their ancestors.” This ignores the many papers T.H. Huxley devoted to the problem of bird origins, as well as consensus that birds had evolved from “pseudosuchians” akin to Ornithosuchus and Euparkeria until just a few decades ago. It is curious why this point was left out, particularly since it is illustrative of the way in which science works! Instead, Coyne gives us the impression that we are simply waiting fore new fossils at which time the scales will fall from our eyes and all will be understood. Sinornithosaurus, Microraptor, and Mei long all receive brief mention, but the evolution of feathers and the fact that feathers are a feature of coelurosaurs (including tyrannosauroids like Dilong) are subjects that apparently didn’t make it in. Coyne lays out the fossils in sequence, but he does not convincingly draw them together and explain how birds evolved.

Third is the evolution of whales, and this section follows the pattern of the previous two. It is not mentioned how we know each of the transitional forms, like Pakicetus and Ambulocetus, are whales, only that they are and fit in sequence. Following that sequence, Coyne mentions Dorudon and Basilosaurus, which he says had “blowholes atop the skull.” This is false. These creatures still had nostrils near the front of their snouts, and even in later forms like the tooth-and-baleen-bearing Aetiocetus the nostrils were still placed in front of the eyes even though they had been move backward. In fact, I am puzzled by why Coyne jumps from Dorudon to modern baleen whales as if there are no more transitional forms (like Aetiocetus). A brief acquaintance with the literature on the subject shows that there is more to the story than Coyne is telling. We are again subjected to a standard account that not only contains a few errors, but fails to convincingly explain how whales went from being terrestrial to aquatic.

I will now jump to the penultimate chapter, the one concerned with fossil hominins. Coyne picks up with the discovery of the “Taung child,”Australopithecus africanus in 1924. Coyne says that this was the first “stepping stone” to understand our own origins. This is false. The debates over “Pithecanthropus erectus” (later Homo erectus) from Java, the Neanderthals, and the Piltdown fossils illustrated the search for our ancestors, whether those ancestors existed among the apes or some kind of “Eohomo.” Coyne mentions some of these finds, but apparently did not dig deeply enough into the debates over them. (Piltdown doesn’t even garner a mention. This is unfortunate. Yes, it gave science a black eye, but better to acknowledge it and confront it than ignore it due to discomfort.) Even when Dart described Australopithecus africanus in 1925, many of his colleagues thought it was a fossil ape and not directly relevant to the origin of our species. The story is more complex than I cannot do justice to here, but suffice it to say that Australopithecus did not get its come-uppance until W.E. le Gros Clark rehabilitated it in the late 1940’s after examining the original fossils himself.

Coyne also repeats a brief summary of the 1925 Scopes Trial seen earlier in the book. He says “In the famous ‘Monkey Trial’ of 1925, high school teacher John Scopes went on trial in Dayton, Tennessee – and was convicted – for violating Tennessee’s Butler Act.” This is a gross oversimplification designed to make Scopes out to be a martyr for science. In truth, the trial was hatched as a publicity stunt, concocted by local businessmen who took up the ACLU’s offer to make a test case against the Butler Act. Scopes was a substitute teacher for a biology class once and was not even sure he mentioned anything at all about evolution. He volunteered to be the victim, and while found guilty, was just a part of a circus that, despite many historical treatments (see Edward Larson’s Trial and Error for the short version and Summer for the Gods for the long one), people still misunderstand. Either Coyne simply rehashed textbook cardboard or refused to acknowledge the actual historical events to make his point.

A curious label also appears on page 197. In an illustration of the ages in which hominins lived, there are labels for A. rudolfensis and A. habilis. These are Homo rudolfensis and Homo habilis, and Homo habilis is referred to in the text. Some think that H. habilis should be grouped within Australopithecus, but no reason for or against this view is presented in the book. It is a minor slip in consistency, but I had to wonder why it was not caught.

Also curious is Coyne’s question “What, then, propelled the evolution of humans?” This makes it sound as if there were only one reason for our evolution, or that it was deigned to be (we were “propelled” toward our present state by an ancient change). By “human,” do we mean the genus Homo, or perhaps hominins in general? Were there not different selective pressures at different times? To his credit, Coyne does point out that evolution is a branching process multiple times, but the concept of evolution towards a particular end still creeps in around the edges.

There is a lot more that I could complain about, but I think I have already gone on for too long. Why Evolution is True is not a bad book, but it is riddled with little errors and oversimplifications. In terms of the content dealing with fossils, transitional forms are paraded out but their connections to one another are generally not illuminated. Precisely how early tetrapods were derived from lobe-finned fish or birds from feathered dinosaurs is not explained, and so Why Evolution is True fosters belief in evolution but falls short when it comes to cultivating understanding.

I’m sure that some will say that I’m being overly harsh on this book, and that may be true. I have reason to be. Over the past two years, as I have been working on my own book, I have spent many hours pouring over papers and books trying to learn about evolution. When I consider the evolution of whales, for instance, I do not simply want to know the names of the animals but how they differ, why they differ, and what that says about how whales evolved. It frustrates me, then, to see an author rehash popular summaries but essentially ignore the details, which are readily available in the literature. It seems that the treatments of transitional fossils in Why Evolution is True were gleaned from readily available popular summaries and there was little actual research that went into these sections.

For a particular audience, Why Evolution is True can be a useful book. If you don’t know much about evolution, but have a craving to know more, it would not be a bad starting place. Otherwise, there’s little that distinguishes it from other popular books that seek to summarize evolution; if you have read one, you’ve generally read them all.

Comments

  1. #1 Frasque
    December 21, 2008

    Sounds like a shameful waste of opportunity. What reading level would you say this is aimed at? Even with flaws, for younger readers it might be a decent stepping stone, although something more exciting might be better (for me it was “The Dinosaur Heresies” at age 12).

  2. #2 RPM
    December 21, 2008

    if “evo-devo” sounds like the name of an 80’s new wave band . . . Jerry Coyne’s forthcoming book Why Evolution is True isn’t a bad place to kick off your intellectual journey.

    I don’t think Coyne’s the person to turn to for a balanced opinion of evo-devo (whatever definition is used to fill that vacant term). Does he cover evo-devo in the book? If so, does his coverage include more than a list of MC1R mutations?

  3. #3 Laelaps
    December 22, 2008

    Frasque; I’d say that if you can handle the red books in “adventures in reading,” you can handle this. :)

    Seriously, though, I’d say that the book is appropriate for high school seniors and above. Some might be able to handle it earlier, others not at all, but it is fairly straightforward. Like I said, it’s a fair introduction to some ideas for general readers who don’t know much about evolution.

    RPM; I was a little concerned about this going in, as well. While Coyne doesn’t give development the same treatment Sean B. Carroll does, he does stress the importance of understanding it. I don’t have the book in front of me, but if I recall correctly he devotes a whole chapter to development. It’s pretty basic stuff, and I’m sure it could have been done better, but he doesn’t relegate it to the sidelines, either.

  4. #4 Gerald Love
    December 23, 2008

    Only a Theory by Kenneth Miller while engaging in the controversy over Intelligent Design delivers a simple and clear explanation of evolution as I have ever seen. I recommend it highly.

  5. #5 SpikeRate
    January 2, 2009

    This review reads as a quintessential example of student-trying-to-play-gotcha-with-the-professor. You’ll notice that the major points are ones based on judgments about the uses of semantics and specific terms (e.g., “in order for a fossil to be formed” means that Coynes doesn’t know the other ways fossils are formed), not based on argumentation of high level concepts. It is also based largely on opinion and subjective judgments which are common student-level complaints easily hurled at anyone writing anything (e.g., “bland”). The author’s self-consciousness and self-appraisal of probably being “harsh” are the final hallmarks of this phenomenon, where no major, directly stated points are addressed and instead lots of nitpicking is done.

    As a scientist in a different field, I wholeheartedly disagree with this review. I encourage anyone with any level of education to read this interesting, accurate, and well-written book on evolution’s empirical and conceptual foundation. Coynes is extremely knowledgeable about the topic, and he has written what I think is one of the best and most accessible books on evolution.

  6. #6 Laelaps
    January 2, 2009

    Spike (I notice you’re not brave enough to tell us who you really are…);

    Is accuracy not important? Coyne not only presents nothing original in the sections on paleontology, but makes a few mistakes. I have duly pointed them out. The sections mentioned are not entirely wrong, but it seems to me that Coyne relied on popular press articles and a few questions to colleagues rather than really researching the topic. I did my best to mention specific mistakes indicative of this phenomenon, and you are entirely wrong to state otherwise.

    I find your commentary entirely offensive. It is as if I am not allowed to enjoy the book because it’s “mostly right” and written by Coyne. Why Evolution is True is little more than a rehash of information produced elsewhere and it fails in its premise to offer the overwhelming evidence for evolution. The book is accessible, yes, but just because a book is non-technical does not make it good!

    Coyne is very knowledgeable about genetics and related fields, yes, but he should have put more effort into areas he was not familiar with. In this review I laid out what I feel to be significant deficiencies in his treatment of paleontology, in particular, as well as some minor mistakes. You would also do well to recall that I recommended this book to those who know almost nothing about evolution but could use a primer on the topic. For those who are already knowledgeable about evolutionary science, though, the book is about as boring as it gets. Your defense of Coyne is admirable, but I am appalled that what I feel are substantial criticisms are brushed aside simply because I am a student. Such is arrogance, I suppose.

  7. #7 Raymond Minton
    January 3, 2009

    I must agree, accuracy in a book is important, and the errors you cited in Coyne’s book are certainly regrettable. Mistakes only serve to undermine an argument, and give the creationists more ammunition. I’ve found mistakes by people who should have known better, even the late Stephen Jay Gould. So please authors, for the sake of the truth and making our argument more effective, please make sure you have your facts right!

  8. #8 SpikeRate
    January 5, 2009

    It’s not that your criticisms aren’t valid or aren’t true because you’re a student; of course not. It’s that I think they are, as I said, nitpicking about minor issues and about omissions of author choice, which are a common tack for students to take. You prefer to call them errors and mistakes, which is a choice of words issue. I entirely disagree with your use of those terms here. So, let’s go through exactly the “mistakes” and “errors” you mention in your review.

    One of the first “mistakes” you discuss is the one-way-to-make-a-fossil “mistake”. But Coyne never claims there is only this one way. You use his failure to explain every possible way as a mistake. I would call that an omission of choice in a book meant for the general public. And this pattern of identifying areas where he might have said more characterizes well the rest of your criticisms, as you’ll see below.

    For example, you state: “Rather than chronologically surveying the whole of vertebrate evolution (the traditional method, exemplified by Prothero’s book, Colbert’s Evolution of the Vertebrates, and Richard Fortey’s Life), Coyne selects a handful of transitions to make his case.” This is precisely my point. He is writing a book for a wide-ranging audience. It is neither a mistake nor an error not to chronologically survey the whole of vertebrate evolution as other books have done. This is not the purpose of his book.

    Going on, Coyne’s use of the term “missing link” annoys you, and that’s your prerogative. I actually liked his use of it because it addresses a common misconception about discontinuities in the fossil record using a term many people know.

    The next paragraph complains of Coyne’s discussion of terrestrial tetrapods, where “no details are given.” Again, I would call this a choice of not explaining many things related to this topic, not “mistakes” or “errors.”

    Continuing regarding whales, your criticism states: “It is not mentioned how we know each of the transitional forms.” Again, I wouldn’t use the terms errors or mistakes to characterize this. This is merely pointing out that more could have been said, which is almost always true. It’s an easy criticism that can be hurled at any book.

    Interestingly, while criticizing Coyne for being incomplete about Piltdown Man, you state in your review: “The story is more complex than I cannot (sic) do justice to here.” So, you’re acknowledging, at least when it serves you, that sometimes there isn’t room to cover everything.

    You make a completely speculative, unfounded, and seemingly unfair point about Coyne’s Scopes sources and about his scruples: “Either Coyne simply rehashed textbook cardboard or refused to acknowledge the actual historical events to make his point.” This is silly at best and unprofessional at worst. Again, neither an error nor a mistake.

    One of the final points made in the review is another omission, that Coyne “does not point out that evolution is a branching process multiple times, but the concept of evolution towards a particular end still creeps in around the edges.” His clarity on this issue is debatable, but again it is easy to argue that an author could have spent more time emphasizing or explaining a particular point. Needless to say, this is neither an error or a mistake.

    So, in conclusion, I present the same argument. I have gone through the review paragraph by paragraph. I would suggest that the book isn’t really so full of factual errors or mistakes, as you suggest. I would suggest that it simply doesn’t cover all details related to every topic it introduces and that these are choices made by the author and editors, not “mistakes and errors”. I maintain that it’s a very well written, accessible, and accurate book on evolution for anyone interested.

    I, of course, never stated that just because a book is nontechnical it is good. But I would say that a book can be very good and also intended for an audience that is broad and includes people who are new to the subject matter. I also never said that you’re not allowed to enjoy the book or that it’s “mostly right.” These are all characterizations by you. You can reread my comments.

    If you have “substantial criticisms”–or even substantive criticisms–by all means, state them. Being a student or not has no bearing on the validity of the arguments themselves. And even if you were a tenured professor, I would still disagree with this review on exactly the same basis I’ve already stated. I simply pointed out that this way of panning a book is common among students.

    The fact that you “find my commentary entirely offensive” and are “appalled” speaks to the possibility that you might have your ego tied up in this thing a bit too much. Reread my comments. You are entitled to your opinion and published it. I am entitled to mine. People should read what we both say and decide for themselves with whom they agree. With any luck, they’ll read Coyne’s book as well (or perhaps your upcoming book), form their own opinion, and maybe learn something about evolution, science, and public discourse in the process!

    :)

  9. #9 SpikeRate
    January 6, 2009

    Regarding identity, let’s let my arguments stand for themselves. As I’m sure you’ll agree, it really shouldn’t matter whether I’m a student, professor, dean, lawyer, musician, janitor, or member of the National Academy of Sciences in neuroscience.

  10. #10 Phil John
    February 28, 2009

    Your review seems overly harsh and, to be frank, nit picking. As an introductory text, it cannot be expected to cover all the topics you discuss in sufficient depth.

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