Previous
Chapter 16
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
Certain tracts of land throughout the more lush and verdant islands of the Galápagos have been cleared for farming and cattle pastures—all of these plant and animal species are new to the islands. In the village of Puerto Ayora, the biggest settlement in the archipelago, finches fly around amongst humans, eating crumbs dropped by people. A librarian at the Charles Darwin Research Station frequently throws rice to the finches that gather around the complex—sometimes, the birds eat right out of her hands, and once, she believes a wounded finch flew into her bedroom, seeking help with its affliction.
The habits of the finches that live in and around Puerto Ayora illustrate their variability—the finches’ lives have intertwined with the humans’. The people of the village live in harmony with the finches, but their relationships are a testament to how easily influenced by environmental pressures and other living organisms these birds truly are. The book suggests that humanity needs to thoughtfully consider how their actions affect the other living things within their ecosystem.
Themes
The arrival of human beings in the archipelago has begun a new phase in the finches’ evolution—but the direction of that phase remains unclear. There are changes taking place, but Peter Grant insists they’re difficult to observe. The finches on the island of Santa Cruz, though, have started to appear more homogenous to the Grants—they seem to be fusing. The lessening pressure of the struggle to survive seems to be “turning [the birds] into a hybrid swarm.” But on the uninhabited islands like Daphne Major and Genovesa, the struggle is still just as intense—the rapidly-changing weather conditions on those islands keeps the birds from ever really fusing.
This passage shows that in situations where a species’ survival is relatively unthreatened, the evolutionary pressures on them will begin to lessen—and as a result, they’ll stop making behavioral changes and developing such starkly different physical characteristics. But in places where environmental pressures continue to fluctuate, constantly encouraging a species to prize different traits at different times, divergence and evolution will continue to unfold at a rapid pace.
Themes
Decades ago, the botanist Edgar Anderson argued that human beings’ presence in new places would lead to increasing hybridization of those places’ plants and animals. The hybrids will require increasingly odd habitats for “optimum development,” he suggested, predicting that the offspring of hybrids would be new and strange and would as such require new, strange environments to thrive.
Botanists have observed this phenomenon from the Ozarks to the Mississippi Delta—farmers who treat their lands slightly differently can cultivate plants that won’t thrive anywhere else. Wherever species that belong to different faunas and floras are brought together, the barrier systems between them break down—and in chaotic times, hybridization helps evolutionary mechanisms to work faster. Humanity is disturbing habitats and intensifying the pressures of selection—and so we’re causing evolution to run “at its maximum rate.”
This passage illustrates how the everyday activities that humanity takes for granted as unexceptional are actually creating unprecedented, exciting, and potentially destabilizing new evolutionary pathways for the plants and animals that share our ecosystems. Hybridization means that more species can survive in rapidly changing or unstable conditions—so the rapid, prolific hybridization of the species around us means that humans will have a harder time eradicating the species whose evolutionary processes we disrupt.
Themes
Get the entire The Beak of the Finch LitChart as a printable PDF.
A giant finch specimen Darwin collected on his first voyage to the Galápagos was found to be extinct just three years after Darwin and his team visited. The birds died, it’s hypothesized, because of the disruption that the arrival of human beings brought to their island. A prison colony had been erected on the island of Floreana, and as they cleared land, planted crops, and hunted wild pigs, the alchemy of the island changed. The large finches were suddenly vulnerable to rats, cats, and more—and at the same time, the cactus plants they fed on went extinct.
Though some species are quick to hybridize in order to survive changes, this passage illustrates a historic example of how human intervention can derail the evolutionary processes not just of different species of plants or animals, but of an entire interconnected ecosystem. Humanity must be more conscious of how its activities can interrupt or annihilate a species’ entire evolutionary history.
Themes
Today, the scientists working at the research station know how fragile the ecosystem of the Galápagos is, and they’re working to save the most vulnerable animals on the islands. The Grants and other researchers like them are careful to wash their belongings in salt water before stepping foot on an island like Daphne Major and Genovesa, where even a single pair of ants could, in a short time, destroy the entire ecosystem and spur evolution events that would forever change the island’s populations.
This passage offers a tangible example of how even the tiniest change to a fragile, isolated ecosystem like those of the Galápagos islands of Daphne Major and Genovesa can have rippling effects throughout the entire biosphere. The Grants recognize the responsibility they shoulder in venturing to these places and inserting themselves into the local ecosystem—and all of humanity, too, should think more carefully about how we interact with vulnerable species in vulnerable places.
Themes
The Hawaiian islands, too, offer a prime example of how fragile ecosystems are. When human beings arrived—bringing species like pigs, goats, rats, mosquitos, roaches, centipedes, and scorpions with them—many native populations went extinct. In 1967, the U.S. Fish and Wildlife Service brought some endangered species of Hawaiian finches to Laysan, a small cluster of uninhabited islands north of the main archipelago—and within just 20 years of their arrival, they began to evolve in different directions.
This passage shows how fragile the planet’s ecosystems truly are—especially those that are isolated, like the Hawaiian islands and the Galápagos archipelago. The introduction of even one new species would be enough to throw such an ecosystem into chaos—and the arrival of many new species at once will always have drastic, irreversible effects on how an isolated species evolves.
Themes
Human beings like the Grants and their fellow researchers are aware that projects like moving the finches to Laysan “tinker” with the course of evolution—it is difficult to preserve a species when human pressure inevitably steers that species toward selection. But there is beauty, as some researchers point out, in the astounding rate of change in places like the Galápagos.
This passage essentially states that there’s no way to keep humanity’s influences entirely out of the way of evolving species of plants and animals. Nevertheless, humanity should marvel at how interconnected, variable, and ever-changing plants, animals, humans, and the ecosystems that sustain us all truly are.
Themes
