Monday, March 12, 2007

Sean Carroll's Making of the Fittest

In his earlier book, Endless Forms Most Beautiful (reviewed here) Sean Carroll took biologists to task in terms of how we teach evolution saying:

"Let's show students embryos, Hox clusters, stripes, spots and all the glory of making of animal form. The evolutionary concepts will follow naturally."

Carroll's fascinating new book, The Making of the Fittest(Norton) follows this strategy by taking a more general look at evolution focusing not only on the forms but also how they are connected to the evolutionary patterns revealed in the DNA. He starts out with a discussion of DNA in forensics, noting the contrast between the acceptance of DNA evidence in forensics with the skepticism in our society about evolution.

He considers it ironic that while people are almost 100% supportive about DNA evidence in the court room, more than 50% of citizens in the United States deny that evolution happens even though the patterns revealed by DNA studies speak more strongly than any other evidence about the reality of evolution. The goal of his new book is to make the case for the reality of evolution beyond any reasonable doubt. He clearly is taking on anti evolutionist and lawyer Phillip Johnson who in his writings during the 1990's tried to cast doubt on the reality of evolution, even though he does not once cite or mention Johnson.

Chapter one introduces us to a fascinating informal grouping of fish called "ice fish" which has a suite of adaptations to the extremely cold waters of the antarctic and he returns to these fish throughout the text to illustrate some of the patterns revealed in the DNA of many organisms.

Chapter two gives a brief and painless introduction to the mathematics of evolution emphasizing the power of even modest amounts of natural selection to affect evolutionary change in populations. He clearly explains the key concepts related to some classic examples of natural selection such as the Pepper moth and industrial melanism, so badly mangled by creationist Jonathan Wells in his Icons of Evolution.

One of the strongest sections is his discussion of fossil genes- for instance, the genes related to smell in which the number of pseudo genes or no longer functioning genes is highest in mammals with color vision. For instance mice have about 160 functional Vtr olfactory receptor genes while of the 200 such genes in our genome in our genome only 5 are functional, the rest are fossil genes. He hammers at this pattern with example after example so that by the time the punch line comes the reader is well prepared. The punch line of course is that fossil genes are evidence against two common erroneous notions: that evolution is progressive and that design or intent are involved in the development of life.

Later, he takes on another creationist canard, namely that evolution cannot give rise to novel biological forms and complexity and he makes his case convincingly using one of the favorite examples of creationists, namely the eye. He discusses the genetic underpinnings involved in the development of animal eyes, and in the rest of the chapter hammers creationist claims with example after example of complexity arising in the absence of an intelligent designer. He picks up one the themes of his research namely that animals share a common tool kit of genes involved in development and body planning.

Next he draws parallels between the tactics of anti evolutionists to Lysenkoism, and opposition of Chiropractors to vaccination noting in all three groups the same basic six strategies to under cut empirical science:

1. Doubt the science
2. Question the motives of scientists
3. Magnify disagreements among scientists and cite gadflies as authorities
4. Exaggerate potential harm
5. Appeal to personal freedom
6. Claim that acceptance (say of evolution or vaccination) repudiates key philosophy

I had to smile at these since this six fold strategy is exactly the one used by the previous Kansas Board of Education in its "hearings" on evolution the other year.

The book also gives many of the standard but important examples of the application of evolution to human problems and ends with a sobering look at how we are inadvertently causing the demise of fisheries due to poorly thought out and unintentional experiments in natural selection. The ending of the book is quite sobering noting that while we debate the existence of evolution our inadvertent evolutionary experiments are destroying the Earth's marine resources.

He leaves us with the question:

"Will we heed these facts and accept our responsibility...or will cod, tuna, marlin, blue whales, dugongs, icefish and more become as rare as palm trees in Wyoming".

The book is a great exercise in clear critical thinking. It is also highly accessible to the non biologist and I hope it has wide circulation.

Other Links:
Interview with Sean Carroll.
Sean Carroll's home page(http://www.molbio.wisc.edu/carroll/)

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