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Chapter 8
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 Grant tells his classes at Princeton that “evolution is always happening.” Grant often cites an example from Darwin’s own life. Darwin built himself a Sandwalk, which he called his “Thinking Path,” on a strip of land belonging to his next-door neighbor. He planted trees and created a trail, and soon, blackbirds came to roost along the path. One very cold March, Darwin noticed that many of the birds on his grounds had died off—over four-fifths of them. Darwin didn’t document the process—but Grant supposes that if he had, he would’ve found something interesting about which birds lived and which died.
The Grants are now, in a way, retracing Darwin’s Thinking Path, gathering the evidence he did not in order to solve the mystery of evolution. They can only speculate about the things that Darwin might have discovered if he’d done certain things differently. And they are careful, in their own work, to pay attention to every shift that takes place around them, no matter how insignificant it might seem, so that they don’t miss out on a potential breakthrough, either.
Themes
How variation leads to the creation of new species is the question that has been at the forefront of many biologists’ and evolutionists’ minds since Darwin’s time. Drawing a link between selection and evolution is one thing—drawing the link between evolution and the creation of new species is another entirely. Darwin’s contemporaries struggled to accept Darwin’s hypothesis that evolution could create entirely new species, writing it off as a “stimulating suggestion.” Even as recently as 1981, the scientific community wrote the hypothesis off as conjecture. But the Grants have trained their eye on the mechanisms of natural selection and evolution—and they can see more than anyone who’s come before them.
This passage shows how while many of Darwin’s contemporaries dismissively discounted his “suggestions” about evolutionary processes, he was actually far ahead of his time. Science has taken a long time to prove what basic logic always pointed toward. As science has advanced, humanity has been able to take a closer look at the formerly invisible processes that are taking place all around us.
Themes
Yet even Peter Grant concedes that the step from variation to entirely new species is a puzzle that will confound people for years to come. Answers, though, seem to be found in the Galápagos. The islands are home to 13 species of finches found nowhere else in the world—not to mention unique species of sharks, mockingbirds, tortoises, iguanas, and more—and there are over 200 plant species unique to the archipelago. The Galápagos isn’t even the most extraordinary hub of speciation on Earth—almost any location in the world, examined closely, reveals a huge variety of plants and animals. There are somewhere between two and 30 million species of animals and plants on the Earth today—and scientists are still asking why.
While it might seem unremarkable at first glance, scientists who take a deeper look at the extraordinary variation in species all over the world find that there are many mysteries to be solved in terms of asking why there are so many different kinds of the same animal (or plant). Variety, it seems, isn’t just the spice of life, as the idiom goes—it’s a necessary mechanism for deciding which species survive and thrive within their respective ecosystems. But scientists are still studying how the relationship between an environment and a living organism can lead to massive swaths of variation.
Themes
The process of evolution is not complete—it is still in action. The Grants continue to test the forces that shape adaptations—and the forces that put new species on the planet. Darwin thought of the branches of life as a massive tree that was grown long ago—but the Galápagos, for example, are so young that the process of animal and plant life’s colonization and creation is still happening there. During their years on Daphne Major, the Grants could watch in real time as strange species of plants grew on islands where they’d never been before, having ostensibly traveled between islands (or even from the South American continent) via the ocean’s current or carried by birds that travel from place to place throughout the archipelago.
This passage highlights the tension between schools of thought that suggest that evolution and speciation are already complete, and those that suggest that new species are still being created before humanity’s very eyes. The Grants’ research has shown that even Darwin’s line of thinking on this matter was outdated. Nature is continuing to grow and change constantly, creating new species to fill new ecological niches all the time.
Themes
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As natural forces—like the massive El Niño—encourage animals to hop between islands and carry new seeds to different places, hybridization continues to rise. And different species, flung together for the first time, begin to breed, producing new sorts of offspring.
Changes in any environment create changes in the organisms that inhabit that environment. Hybridization and variation are responses to these kinds of environmental changes—plants and animals are creating new forms that will be better-suited to an ecosystem’s variable challenges.
Themes
