The Beak of the Finch.

Winner of the 1995 Pulitzer Prize for Non-Fiction, Jonathan Weiner’s The Beak of the Finch: A Story of Evolution in Our Time should have ended most of the inane arguments still coming from creationists and other science deniers about the accuracy of the theory of evolution. Weiner tells the story of the Grants, a married couple of biologists who spent 20 years studying Galapagos finches – the same species that Darwin spotted on his voyage with the Beagle and that helped him develop his first theory of adaptation via natural selection – and observed natural selection and evolution in action. This remarkable study, which also showed how species evolve in response to changes in their environment and to other species in their ecosystems, was a landmark effort to both verify Darwin’s original claims and strengthen them in a way that, again, should have put an end to this utter stupidity that still infects so much of our society, even creeping into public science education in the south and Midwest.

The finches are actually a set of species across the different islands of the Galapagos, with the Grants studying those on Daphne Major, an uninhabited island in the archipelago that has multiple species of finch existing alongside each other because they occupy different ecological niches. Over the two decades they studied these species, massive changes in weather patterns (in part caused by El Niño and La Niña) led to years of total drought and years of historically high rainfall, with various species on the island responding to these fluctuations in the environment in ways that affected both population growth and characteristics. The beaks of the book’s title refer to the Grants’ focus on beak dimensions, which showed that the finches’ beaks would change in response to those environmental changes. In times of drought, for example, the supply of certain seeds that specific finch species relied on for their sustenance might become more scarce, and there would be a response within a few generations (or even one) favoring birds with longer or stronger beaks that gave them access to new supplies of food. Many Galapagos finches crack open seed cases to get to the edible portions within, so if those seeds are rarer in a given year, the birds with stronger beaks can crack open more cases and get to more food, given them a tangible advantage in the rather ruthless world of natural selection.

Weiner focuses on the Grants’ project and discoveries throughout the book, but intersperses it with other anecdotes and with notes from Darwin’s travels and his two major works on the subject, On the Origin of Species and The Descent of Man. He incorporates the discovery of DNA and how that has accelerated our ability to study and understand evolutionary changes. He goes into the famous example of the white English moth that found itself at a severe disadvantage in the polluted world of the early Industrial Revolution, and how a single gene that determined wing color led to a shift in the moth’s population from mostly white to mostly black (to match the soot covering trees near Manchester and London) – and back again after England finally took steps to clean up its air. This one example is especially instructive in our ongoing experience of climate change, which Weiner refers to throughout as global warming (the preferred term at the time), and opens up a discussion about “artificial selection,” from how we’re screwing up the global ecosystem to antibiotic resistance to the futility of pesticide-driven agriculture (with the targeted pests evolving resistance very rapidly to each new chemical we dump on our crops).

Although Weiner doesn’t stake out a clear position on theism, the tone of the book, especially the final third, goes beyond mere anti-creationism into an outright rejection of any supernatural role in the processes of natural selection and evolution. While that may be appropriate for most of the book, as such processes as the development of the human eye (the argument about the hypothetical watchmaker) can be explained through Darwinian evolution, Weiner does overstep when he discusses the rise of human consciousness, handwaving it away as perhaps just a simple change in neurons or a single genetic mutation that led to the very thing that makes us us. (Which isn’t to say we’re that different from chimpanzees, with whom we still share 99% of our genes. Perhaps David Brin was on to something with his “neo-chimps” in the Uplift series after all.)

The most common rejoinder I encounter online when I mention that evolution is real is that we can’t actually see evolution and therefore it’s “only a theory.” The latter misunderstands the scientific definition of theory, but the former is just not true: We do see evolution, we have seen it, and we’ve seen dramatic shifts in species’ characteristics in ordinary time. Some speciation may occur in geological time, but the evolution of new species of monocellular organisms can happen in days (again, if you don’t believe in evolution, keep taking penicillin for that staph infection), and natural selection in vertebrates can take place rapidly enough for us to see it happen. If The Beak of the Finch were required reading in every high school biology class, perhaps we’d have fewer people – the book cites a survey from the 1990s that claims half of Americans don’t accept evolution – still denying science here in 2018.

Next up: David Grann’s Killers of the Flower Moon: The Osage Murders and the Birth of the FBI, among the favorites to win the Pulitzer for Non-Fiction this year.