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Chapter 2
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
Peter and Rosemary Grant were both interested in the variation of animals and plants from a very young age. Darwin, too, studied variation from a young age, focusing on a study involving barnacles in 1846. While a colony of barnacles might appear homogenous (or the same), Darwin found remarkable variations between his specimens. He became frustrated, wondering where he should draw the lines between different species. The study confirmed for Darwin that “there is no species barrier”—in other words, that one species can shade into another. Darwin assumed that this shading (or splitting) of species was a process too slow for him to observe. But in reality, it’s a process that can indeed be seen happening each day in places like the Galápagos.
This passage shows how Darwin’s initial understandings of the process of selection, speciation, and evolution paved the way for newer generations of naturalists to understand more about the world around them. Darwin provided the theory—but, again, constrained as he was by the resources available to him, he could not observe it in practice. But further generations of researchers have been able to observe this process in action—and develop a greater understanding of the interconnectedness of all aspects of the natural world.
Themes
As ornithologists studied Darwin’s finches, some split them into species—others lumped them together. Today, most taxonomists consider the 13 species of Galápagos finches to be a single family or subfamily, divided into four genera. In the first genus, the birds live in trees and eat fruit and bugs; in the second, they live in trees and are herbivores; in the third, the birds live in trees but look and act like warblers (another species of bird entirely); in the fourth, the birds live on the ground. Within the ground finches, there are three distinct species (G. magnirostris, the largest; G. fortis, the medium; and G. fuliginosa, the smallest). Within each of those species, there are variations in the finches’ beaks, but it is said at the Galápagos research center that only God and Peter Grant can tell the finches apart on sight.
This passage illustrates the Galápagos finches’ intricate development. While all of the birds might appear the same to the untrained eye, there is a vast network of biological, social, and behavioral differences underlying their apparent similarities. The beaks are evidence of how the finches have evolved to become different from one another time—and, again, symbolic of how evolution is a real, observable, ongoing process.
Themes
In the 1970s, Peter Grant had begun to wonder why some species of animals and plants were hypervariable (prone to lots of variation), while others weren’t. In order to study this phenomenon, he needed to observe a hypervariable species over a long period of time—and Darwin’s finches were ideal for his purposes. Peter and Rosemary first traveled to the islands in 1973, bringing along their young daughters. There, they found the birds to be extremely tame—the birds did not recognize humans as predators due to their isolation, and they would perch on the Grants’ shoulders or eat out of their hands. The finches, it seemed, were studying the Grants, too.
The Grants were fascinated by the finches—but as they began spending more and more time among them, the Grants began to realize that the finches were still learning about their environment. They knew that they would have to be careful in their study of the finches, because any small disturbance could change the course of the finches’ ongoing evolution. This illustrates the delicate balance between the natural world and the humans who long to better understand it.
Themes
That first year, the Grants hopped between seven different islands, meticulously measuring the finches. They found that while most species of birds elsewhere in the world have beaks that are so identical in shape and size that only four in 10,000 might have beaks that deviate from the mean, on the Galápagos, about four in 100 finches had beaks of different sizes. Even Darwin, the Grants quickly learned, had not realized how extremely variable his finches were.
When the Grants discovered how incredibly variable the Galápagos finches’ beaks were, they knew that they’d have a unique opportunity to study selection and evolution in action. A species that is highly variable—meaning that there are plainly observable differences between different individuals of the same species—is a species that is still figuring out what its final form will be. Thus, evolution is in progress on the island of Daphne Major.
Themes
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