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4 of 4 people found the following review helpful:
5.0 out of 5 stars
Light, Eyes, and Evolution, June 14, 2006
Charles Darwin, among the most candid of all scientists, did not pretend all was well when he came across counter-arguments to his ideas. In fact, he deliberately included possible objections to his own proposals; not only did this give him an opportunity to respond to them, he realized that it was fair and objective to attempt to give all sides of ideas he knew were controversial. The eye gave him restless nights. Indeed, he considered it one of the "organs of extreme perfection and complication" and wrote "To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree." Creationists are fond of citing this quote out of context, forgetting that the operative verb is "seems" and that Darwin immediately follows up to show why all is not what it seems. Such an organ could have evolved, especially if one considers the many degrees of complexity in different rudimentary or sophisticated animal eyes. More evidence has been the recent discoveries that rudimentary eyes as well as the sophisticated ones of us mammals or of octopuses have some identical genes, indicating a common foundation.
Nonetheless, Darwin considered the eye an organ of perfection; he considered that nothing got past the eye. It is this burden of assumed perfection that Andrew Parker lifts in _Seven Deadly Colours: The Genius of Nature's Palette and How it Eluded Darwin_ (Free Press). Parker shows that eyes certainly lack the sort of perfection that Darwin imagined, that different animal eyes have very different capacities, that there is no perfect eye able to take all visual stimuli in, and that creatures have evolved to take advantage of the imperfections in the eyes of others. Among the surprising facts here is that color is not just pigment, like the paints an artist applies to a canvas. "Behind the scenes of a colour lies a microscopic factory, responsible for the light that leaves an animal's body or an artist's paint." But pigments are only one color factory; there are many others. In fact, in each of the seven chapters of Parker's book (laid out for the seven colors of the rainbow minus indigo but plus ultraviolet), there are other ways of manufacturing colors. In the chapter on violet, for instance, an examination of the iridescent violet colors of wings of the Malayan Eggfly butterfly shows no violet pigment - you could try to grind such wings to make a violet dye, but you would fail. The color from them is "structural" - it comes from astonishingly complicated microscopic structures on the surface of the scales of the butterfly, the layers of which are at a distance from each other which can reflect only the violet colors in phase.
Each chapter ends with "A tonic for Darwin", an explanation of how all eyes have imperfections and that there can always be found some pigment, reflection, or blur which an eye cannot see. Darwin assumed simply that color was color and not subject to faulty eyes within an environment. He would have been fascinated by the visual arms races described here as one creature after another balances conspicuousness (for warning or attraction of mates) with camouflage, and predators change their own tactics to take advantage of any alterations. The perfection which Darwin saw in eyes, and which he thought a possible objection to his concept of descent with modification, is illusory; the imperfections, as revealed here in a stimulating and clear book, form more evidence to support his theories.
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3.0 out of 5 stars
A valuable reference, February 14, 2009
This book is absolutely packed with fascinating discoveries.
Parker writes with a contagious enthusiasm. Each chapter is structured like a "whodunit" mystery, with a striking payoff at the end. 'Seven Deadly Colours" is one of those rare science books from somebody who really knows how to tell a story. This is honestly one of the most entertaining natural history books in my collection.
Parker, being aware of recent controversies surrounding the work of Darwin, is at pains to use the book on the whole as a long argument to show that the characteristic features of animal eyes, far from being perfect (and therefore inexplicable by any means other than ex nihilo creation)are highly contingent, adapted for specific functions and built from inherited components. The book is full of terrifically clear examples of behaviour and physical adaptation to very precise conditions. In that respect, it is a rich resource for anyone interested in deepening their practical understanding of evolution.
I found Parker a little crude though, when it came to more abstract discussion of evolutionary theory. I also found him somewhat ham-fisted in his periodic attempts to link the books content back to a defense of Darwin.
That is a minor criticism though. It simply means that if you are of a philosophical bent, or are looking for a book to assist with deeper theoretical questions about evolution, you will find great material here -but don't expect the author to always join the dots for you in an entirely satisfying way.
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