Friday Book Notes

17 08 2007

Yesterday I wrote down a few thoughts on the first half of Jack Horner’s book Dinosaur Lives, and I can’t say the second half of the book was much better than the first. Decrying the current public misunderstandings about evolution, Horner tries to take on the subject himself, but the attempt doesn’t come off especially well. First, he attacks Eldredge & Gould’s idea of punctuated equilibrium, seeing it more as a theory that ends queries way too soon rather than an understanding of speciation and evolutionary rates. Horner also has issues with the Linnean system of taxonomy & systematics, preferring cladistics, but then saying that cladistics doesn’t have all the answers either. In this area I agree about some things (i.e. still using designations of modern species to keep related groups apart, like putting dinosaurs in “reptiles” while birds get a class to themselves despite being derived from dinosaurs), but overall no alternate system is proposed to fix problems based entirely based on extant taxa or morphology out of context with the stratigraphic record. Although Horner had been dropping species names left and right throughout the rest of the book, when he comes to the evolution of some centrosaurs he holds back on their binomials, instead calling them centrosaur I-IV, which makes that section more complicated than necessary (especially since it appears that Horner has put together a good case for the anagenesis of Pachyrhinosaurus within the Judith River Formation). This is followed up by some intellectual meanderings about souls and an afterword about commercial fossil collecting, but overall I can’t say I really enjoyed the book. It might serve biographers of Jack Horner well, but the actual findings about “Dinosaur Lives” seemed to be of secondary importance in the book.

The Third Chimpanzee by Jared Diamond

Last fall this book was recommended to me by a professor of mine, although I merely added it to my amazon.com wish list and forgot about it for a time. Finally having the chance to pick it up last week, I was looking forward to reading this one (despite the very “March of Progress”-like illustration on the cover). 50 pages in, however, I can’t say I’m exactly impressed. As I noted in my big post on how we think about human evolution, popular works about human evolution these days are far more focused on living apes (especially chimpanzees and gorillas) than fossil ones, many authors taking the behaviors/habits/morphology of living apes and extrapolating backwards, usually paying little heed to the fossil record. Diamond falls into the same trappings, opening the book with the genetic tests conducted by Sibley and Ahlquist showing that we share over 98% of our genetic code with chimpanzees. This difference, the author repeatedly states, is greater than the difference between White-Eyed and Red-Eyed Vireos, and in a perfect world chimpanzees would be called Homo troglodytes (bonobos being Homo paniscus). While Diamond evokes cladistics, however, this new plan seems to ignore evolutionary history, using the data from the tests conducted circa 1992 to rearrange the taxonomy. While there’s no doubt at all that chimpanzees and bonobos are our closest living relatives, I think there are more than enough differences between us to classify us as different genera, especially since we are on diverging evolutionary paths. Further, different tests for genetic similarities seem to have come up with different results, and while I don’t expect the overall “% relatedness” figures to drop drastically, I think as we refine our understanding of genetics and evolution we’ll be better able to put our finger on how different we are from living apes and why that is.

Diamond does wade into paleoanthropology a bit (although he usually calls is archeology), although his treatment here isn’t much better. Statements are rattled off quickly, everything we are told about ancient hominids being related to Diamond’s experience with people in New Guinea, who (according to the author), just stepped out of a “Stone Age” way of living. This problem of differentiating between possible correlation and causation (or other significant pattern) seems to be a recurring problem through the first section, and at some points the reader is simply told that this or that fact is true without any support. Considering whether the ancestors of modern day humans and Neanderthals interbred, Diamond relates the idea to a sexist adventure/time-travel novel, concluding;

Believe it or not, something like that experiment [sex between Homo sapiens and Homo neanderthalensis] actually took place. It happened repeatedly around forty thousand years ago, at the time of the Great Leap Forward.

No evidence is offered to support this view, and it seems that Diamond is merely arguing from authority or expecting the reader to believe the hypothetical situation because he wrote a book. When writers take such approaches, I don’t feel respected by the author, and there is no footnote or citation that would help the inquisitive reader find out more on the subject if they were so inclined. Perhaps later chapters of the book will be better (Diamond seems a bit out of his element in terms of paleoanthropology), but somehow I get the feeling that this book will be very much like de Waal’s Our Inner Ape and Peterson/Wrangham’s Demonic Males in that molecular studies and cultural anthropology will trump other fields more concerned with “dusty old bones.”


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4 responses

18 08 2007
John Wilkins

I agree about Diamond. The “Great Leap Forward” is a fiction of his own devising, with no real evidence in its favour apart from “that’s how it must have been”.

On Horner, I think he is confused, as I think anyone who still believes in a grade-clade classification system is confused. They are orthogonal to each other; either classify by clade, in which case dinosaurs aren’t reptiles or birds are, or don’t, in which case the whole system need not rely on ancestry at all.

18 08 2007
laelaps

Thanks for stopping by and commenting, John. The more I read up on what we think about human evolution at different times, the more I find that there’s not really any popular resource that I would consider especially adequate; when someone asks me what books they should read on the subject I usually have to recommend a stack and say “Take daily with a grain of salt.”

I agree about Horner too. The problem is that he seems irritated by classification, but he never really expands on his views, which just makes the passage more of a rant than anything else. Overall the book wasn’t very satisfying, and I won’t even go into the meanderings on souls and the half-joking manner in which the “spirit” of a deceased friend is said to be present in pelicans/herons throughout the book.

18 08 2007
Christopher Taylor

I’m a long-time anti-strict-monophyletist turned very grudgingly into a monophyly-as-much-as-possible-ist😉. Any system of classification is going to be deficient in some way, as we are attempting to represent a multi-dimensional structure in a two-dimensional branching system. Monophyly does at least have the appeal of being able to objectively demonstrate where you are making your divisions, and hopefully discourages the vast amounts of paper that have been wasted in the past as two researchers argue for different classificatory systems from the exact same theories of evolutionary relationships.

In terms of Homo troglodytes – that’s what it was once, wasn’t it? But as I’ve said before, generic delimitations are entirely arbitrary, and there is no real objective “genus rank”. Sinking Pan into Homo would also require sinking all known fossil hominins into Homo. This change for no good reason would just confuse matters, without really telling us anything new.

20 08 2007
Utenzi

I enjoy Diamond’s books but I take what I read with a grain of salt. Or two or three. Like many people that become famous, I think Diamond–and Horner too for that matter–has bought into his own myth. Once a person has done that, credibility suffers because they have trouble believing they can be wrong.

Of course I could be wrong about that, Brian. 🙂

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