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Chapter 7
Themes
Key
LitCharts assigns a color and icon to each theme in The Beak of the Finch, which you can use to track the themes throughout the work.
Natural Selection and Evolution as Ongoing Processes
Nature and Humanity
Evolution, the Modern Era, and Nature’s “Resistance Movement”
The Interconnectedness of Species and Ecosystems
Hybridization and Specialization
Summary
Analysis
Jonathan Weiner is with Rosemary Grant in her office at Princeton. It is 1991, and Rosemary and Peter are planning on taking a sabbatical—a year without teaching so that they can analyze mountains of data from their time in the Galápagos. The Grants just got back from the archipelago a couple of weeks ago, and already they have begun to sift through it all. They can look through the data and see the mating patterns and family trees of every individual finch on the island. The Grants talk about the finches intimately, and they remember the most minute details of the finches’ lives offhand.
The Grants’ careful observations of the finches have led to a genuine interest in the minutiae of the finches’ lives. The Grants are aware of how their presence on the island stands to affect the finches, and they take their responsibility to preserving the finches’ habitat very seriously. This illustrates that humanity must resist the temptation to interfere with nature’s processes—otherwise, the organic forces of natural selection and evolution might become compromised.
Themes
The Grants’ data doesn’t just cover their finches’ lineages—they have data sets on vegetation, seeds, and transcribed birdsongs. All of this will help them, during their sabbatical year, to delve into the “secrets they were too close to see” while on the island. Here in Princeton, as they look at the mating patterns of a certain family of finches, they find themselves surprised and excited by an anomaly—the finches are pairing off with finches of different species. Hybridization—a crossing of species—is taking place. And what’s even more exciting to the Grants is that the hybrid fledglings are surviving and going on to create their own family trees.
Just as Darwin was limited by the constraints of his time, the Grants, too, must operate within certain constraints on the island. But back on the mainland, they have access to exciting new technologies that help them to process and understand their data in order to comprehend the rapid changes that are taking place on Daphne Major. By introducing the concept of hybridization, the book opens up a new line of inquiry and begins to observe how the Grants will approach it. Change is happening on the island too fast for even the experts to see up close, and nature is doing surprising things.
Themes
Hybridization isn’t unprecedented in nature, and in fact animals of different species breed all the time—such as horses and donkeys, the pairing of which creates mules and hinnies. But mules, for instance, are always sterile, and hinnies rarely breed (though they can). The Grants assumed that any hybridized finches born on Daphne Major would be unfit, and would not live long—but now, the hybridized finches on the island are thriving. These “misfits” are not suffering the disadvantage they might be expected to.
This passage further explains the concept of hybridization, illustrating why it’s so strange and exciting that new hybrid finches are beginning to thrive on Daphne Major. Hybridization isn’t a liability, as the Grants previously thought; instead, it seems to be strengthening these new finch populations in unexpected ways.
Themes
As the Grants work to analyze their data, they find that before 1983—the year of the flood—there were 32 fledgling hybrids on the island. None of them bred at all until the flood—they were unfit. But after 1983, the hybrids have done better and become more likely to breed. The purebred finches still haven’t replaced their numbers on the island, but the hybrids have more than replaced themselves, by a factor of 1.3. “Something has changed since the flood,” Weiner writes—and the Grants’ research on the finches’ hybridization has the potential to unlock the mystery of the origin of species.
Evolutionary processes aren’t just ongoing—they’re often mysterious while they’re still unfolding. The Grants aren’t sure, in this moment, exactly what has “changed since the flood,” but they know that something significant is going on. This section of the book is pivoting toward a deeper understanding of what hybridization means for the world’s species—and how it might influence ongoing evolutionary events all over.
Themes
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