Evolution is under attack, as it has been since Darwin first published his work over a century ago, because it is a theory. As Weiner observes, "observation and experiment are the fundamental tools of science" and evolution, unlike other scientific theories (such as Newton's theory of gravity), did not lend itself to scientific experiment. Until now.
The Beak of the Finch focuses on the work of Peter and Rosemary Grant, two British-born biologists who have devoted most of their professional life to documenting evolutionary change among Darwin's finches, thirteen species that are found only in the Galapagos Islands. What they have demonstrated, through field work and meticulous statistical analysis, is that evolution can be observed in "real time", not just through the study of fossils. "Darwin did not know the strength of his own theory," Weiner tells us. "He vastly underestimated the power of natural selection. Its action is neither rare nor slow. It leads to evolution daily and hourly, all around us, and we can watch."
By documenting the work that the Grants have done, Weiner also shows the unglamorous, but essential, side of research. Research means camping on a deserted island, where you capture birds and release them (after you have put an identifying band on their legs, weighed them to a fraction of a gram, and measured their beaks to a tenth of a millimeter). You record their songs, document what they eat, and count the number of seeds in a specific patch of ground. Then you and your graduate students repeat this process on the neighboring islands. When you are done broiling in the sun or getting soaked in a once-in-a-century downpour on the islands, you move on to your lab. There you spend months creating family trees and analyzing mountains of data. But from this tedious and meticulous work, the Grants have shown that Darwin's theory can be demonstrated in nature. Evolution is going on, today.
In addition to describing the Grants' work, Weiner introduces us to other evolutionary biologists, such as John Endler. Endler observed that guppies in Trinidad and Venezuela have different patterns of camouflage spots depending on which predators are present. So Endler did laboratory experiments at Princeton to demonstrate that the coloration will change, over several generations, as the predators change.
But why should we be concerned about evolution? Because it is not just the beaks of finches or the spots on guppies that are changing. We humans are wreaking huge changes in the environment. Some are easy to see -- native wildlife disappears as urban areas expand. Some are unintentional -- drug-resistant diseases (like tuberculosis) are on the rise as microorganisms evolve in response to the use of drugs. Some are intentional -- as agri-business develops genetically modified crops. As Weiner puts it, "Our wild acceleration of life's central process makes the study of evolution excruciatingly timely."
I should note that a few members of the SWE CD Book Group felt the book dragged. If you start it and get bogged down, please jump ahead and read Chapter 18: The Resistance Movement. Weiner presents a timely discussion of how and why drug-resistant diseases and pesticide-resistant pests are increasing. He raises important questions about humans' impact on nature, and I recommend this book highly.