I have just finished reading The Greatest Show on Earth. I realise that this puts me way behind everyone else, and therefore it is probably somewhat pointless to review it, as most people likely to read this will have already read the book! Still, I want to give it a go, as I thought it might be interesting to write the occasional book review, and this is an easy one to start with.
TGSOE, for those who are not aware, is Dawkins’ attempt to lay out in one book the current evidence for evolution. His previous books have been more focused on explaining what evolution is and how it works, and while this inevitably involved much discussion of the evidence, he admits that nowhere has he set down an explicit catalogue of the evidence that evolution is real. I agree that this is worthwhile, not just from the perspective of refuting creationism, but also as an endeavour in its own right; the science is fascinating in any case, it is always worth knowing on what evidence a scientific consensus is built, and (outside of undergraduate evolution textbooks) the evidence for evolution is not often presented succinctly in one place.
This book fulfils that role admirably. Logically structured, it takes us on a tour of the various types of evidence that show evolution in action (or the ghost of evolution past), dealing with creationist misconceptions along the way. Artificial selection, fossils, biogeographical patterns, developmental evidence, genetic and morphological parallels and divergences among species, relations between predators and prey, the ever popular ‘bad design’ of features such as the vertebrate eye (easily comprehensible under an evolutionary account) and more; all are discussed using up-to-date evidence, alongside explanations of how the evidence itself is collected and understood. Crucially we are shown how independently strong lines of evidence all come together to build a very strong case, such that: “Even if not a single fossil had ever been found, the evidence from surviving animals would still overwhelming force the conclusion that Darwin was right”.
I was glad to see that from time to time we are even given examples of how evolutionary theory might in principle be falsified (ie. shown to be false) – presumably to forestall the bizarre creationist argument that evolution is not real science because it is not falsifiable (I suspect this stems from a basic confusion between ‘is not falsifiable’ and ‘has not been falsified’). These are usually specific examples that could refute specific aspects of evolution (rather than disproving it generally), like Haldane’s well known ‘fossil rabbits in the Precambrian’.
A couple of negatives. Firstly, there is frequent use of the phrase ‘living fossil’. Yes, it always sits between quotation marks, and I realise that it is a commonly used phrase that people may find evocative, but I have to admit that I do not care for it, and I am not alone. At one point Dawkins’ even goes as far as to suggest:
“…’living fossils’ like Lingula which, in extreme cases, have changed so little that they might almost interbreed with their remote ancestors, if only a matchmaking time-machine could procure them a date.”
Well, I suppose he’s hedging a bit with the ‘might almost’ there, but I’m confident that no, even with the assistance of a time machine, interbreeding between individuals and their remote ancestors would not be possible. As pointed out by Dawkins himself elsewhere in the book, even where there is little or no obvious morphological change in a species, its genome will continue to change, making individuals separated by vast tracts of evolutionary time genetically incompatible. Dawkins must know this, so the above comment seems a little odd.
I did also spot one outright error*. In the section on radioactive clocks, when first being introduced to the isotopes of carbon we are told that:
“There’s also carbon-13, which is too short lived to bother with…”
Dawkins is right to think that carbon-13 is of no value to radiometric dating, but that is precisely because it is not short-lived at all; carbon-13 is a stable isotope and is much more common than carbon-14, making up about 1% of the world’s carbon.
But these are relatively trivial objections to what is an otherwise outstanding work of popular science. Having read much of Dawkins’ output, sitting down with this book was like settling down with an old friend. The writing is unambiguously clear and engaging, and the book sparkles with warm good humour and genuine enthusiasm for the subject. I personally enjoyed the book very much. Being a biology graduate, and having read a decent amount around the subject, I found that there was little in there that I had not encountered before. However, I enjoyed this refreshingly presented and updated account, not just as a renewal of my understanding of the evidence, but also as an introduction to some of the more recent examples discussed in the book. Of course, it is also a useful resource to prepare for any encounters with creationists, or even just for conversations with people who are unfamiliar with the evidence and have got the impression from somewhere that the very idea of evolution is still controversial. I would have no hesitation in recommending this book to anyone I knew who had questions about the evidence for evolution, or wanted to learn more – as it handily brings so much good information together in one easily understood package.
*[Post Script – added 23/06/10. I had a look at the paperback edition in a local bookshop today, and the offending sentence has been changed to “carbon-13, which is too rare to bother with…”. I say changed, rather than corrected, because this is not much better, especially since in both editions the sentence continues “and carbon-14 which is rare but not too rare to be useful for dating relatively young organic samples…”. This leaves the reader with the impression that it is the relative rarity of carbon-13 that makes it useless for dating, but as I pointed out, this is not the case – it is because it is a stable isotope. It does not undergo radioactive decay, so the amount of carbon-13 in a sample is not directly related to its age. Furthermore, if carbon-14 is “not too rare to be useful” but carbon-13 is “too rare to bother with”, this implies that carbon-13 is rarer than carbon-14, which is wrong. As Dawkins himself points out later in the book, “about one [carbon] atom in a trillion is carbon-14”, while I’ve told you that about 1% of all carbon on earth is carbon-13. I know this a bit of a pedantic moan about relatively trivial details, but it was a stupid mistake to start with, and ‘correcting’ it with something just as wrong seems weird.]