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Chapter 18
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 have witnessed, together, the transformation of the idea of evolution from theory to fact. Now, they’re witnessing something else: the transformation of the idea of climate change from theory to fact. Global warming began in Darwin’s era—around the 1880s—and the 1980s were the warmest decade of the 20th century. The amount of carbon and other gases and pollutants in the atmosphere is rising, and heat is becoming trapped in our atmosphere. The Galápagos Islands are particularly vulnerable to the effects of warming, because the seasons there are driven by the ocean currents. When temperatures change, so too do the flows of the Earth’s ocean currents.
Many people didn’t believe Darwin’s theories for a long time—but the book underscores that they were true all the same. Now, it is difficult to get lots of people to accept that climate change is real, and that it presents an existential threat not just to humanity but to the evolutionary processes that are unfolding each day all over the world. Humanity has a responsibility to accept our role in the climate crisis and do what we can to prevent the evolutionary processes of the Earth’s species from being interrupted or derailed forever.
Themes
If the seasons in the Galápagos weren’t so variable, the finches wouldn’t need such variable beaks. A change in the ocean’s currents—and thus the seasons on islands like Daphne Major—would mean an enormous, rapidly evident difference in the evolutionary patterns of the animals that call the Galápagos home. The freakish weather the Grants witnessed in the early 1980s, it turns out, might not have been coincidence. It could have been a casualty of warming (and a sign of more intense changes things to come).
Darwin’s finches are the special and extraordinary animals they are because of the environment in which they live and the unique pressures it places upon them. If those pressures are thrown into overdrive, there’s no telling what the damage to the fragile finch populations might be—especially among the new hybrid populations that are just beginning to thrive and branch out.
Themes
If global warming did cause the El Niño of 1982, and if the planet continues to warm, selection will create more fusion in the species of finches on Daphne Major. And the return of selection’s role in keeping the species varied could take a long time to come. The harder and more frequently the Galápagos are hit by extreme weather, the more quickly the finches will fuse—that process, given climate change’s current trajectory, could take only a century.
This passage illustrates how human-hastened climate crisis stands to erase millennia of intricate evolutionary processes around the world. The book stresses that if humanity doesn’t recognize its role in the world’s ecosystem, entire species could be wiped off the map.
Themes
Humanity’s power to drive Darwin’s process has been observed before: in 1848, a Manchester lepidopterist (a naturalist who studies moths and butterflies) named R.S. Edleston realized that a species of whitish-gray moths with black stripes were turning black. The moths, it turned out, were evolving to better camouflage themselves amongst the grimy, soot-stained buildings of the city, which was at the epicenter of the Industrial Revolution. The moths’ relatives in the countryside weren’t evolving—their color remained the same as they had long been. In the middle of the 20th century, after Britain enacted clean-air legislation, the moths began evolving back to their former states.
This passage illustrates just how profoundly the plants and animals that surround us are at the mercy of humanity’s actions. Human activity can force major evolutionary events within the ecosystems around us—and often, we’re not even looking closely enough to notice. Humanity, this passage suggests, has a responsibility to work to understand how our activities impact—and often threaten—the species with which we share the planet.
Themes
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The carbon dioxide that drives global warming is just like the soot that turned the moths black—only it’s invisible, and it’s everywhere instead of concentrated in cities. In other words, it’s pressurizing selection processes in ways we can’t yet see. Another force influencing and accelerating evolution is genetic engineering. Some genetic engineers who work to create different strains of crops and (even different varieties of mice) in their labs call their work the Generation of Diversity, or G.O.D. for short.
Humanity is, in several ways, rapidly changing the environments of life without fully understanding the consequences our actions might create. By pointing out that many genetic engineers cheekily compare their work to God’s, Weiner is point out humanity’s hubris, or overabundance of pride and recklessness.
Themes
To understand our present, Weiner posits, we must look to the past. Darwin’s finches, then, become symbols and heralds of the events taking place everywhere around us. The whole planet, now, is a demonstration of the power of Darwin’s processes—and humanity is both the effect and cause of those processes, a relationship many might prefer not to contemplate. Only five times in the entire history of the world, the fossil record shows, has there been this much “havoc” on the planet—and all five times, most of life on Earth went extinct.
This passage suggests that we are presently in the midst of one of the most dramatic evolutionary moments since evolution began. The “havoc” on our planet suggests that something big is about to happen. But this moment isn’t unprecedented in the fossil record—and, in fact, the big event that might be on the horizon could very well be a “stabilizing selection” event that threatens all kinds of life forms on the planet. Humanity must recognize the fragility of its environment.
Themes
