The Sixth Extinction: Chapter 3 Summary & Analysis

In 1832, William Whewell, president of the Geological Society of London, coined an important word: “catastrophist.” While this word has taken on some new meanings since 1832, Whewell didn’t mean it as an insult: a catastrophist, as he understood it, was a scientist who believed that the history of the planet was characterized by sudden, global catastrophes that caused large numbers of species to go extinct. The opposite of catastrophism is uniformitarianism, which is closer to Darwin’s idea of species and landscape gradually changing in tandem.

One early “uniformitarian,” an associate of Whewell’s, was the geologist Charles Lyell. Lyell was an Oxford-educated scientist who’d been friendly with Cuvier. Lyell studied the rocks of Paris, Italy, and England, and found no evidence that there had been a global catastrophe that caused species to go extinct—all the evidence pointed to a slow, gradual process of erosion in the planet’s geological structure. Lyell proposed that, while some species certainly went extinct, extinction was a slow, gradual process, not a sudden, catastrophic mass-death. Lyell was a popular lecturer and author who toured the U.S. popularizing his ideas about geology.

One of Lyell’s most important readers was Charles Darwin, who was in his early twenties at the same time that Lyell was a major figure in the scientific community. Darwin sailed onboard the HMS Beagle, where he worked as a scientific researcher in the Galápagos Islands, among other places. After returning from his long voyage, Darwin began to develop his famous theory of evolution to explain the existence of some of the strange animals he’d encountered. Throughout this influential and historic voyage, Darwin was a prodigious reader of Charles Lyell’s writings.

Although Lyell was an important advocate for the principle of gradualism in geology—he believed that the geological world was changing in small, almost immeasurable ways—he didn’t believe in any theory of evolution. Darwin disagreed with Lyell, and proceeded to apply Lyell’s principles of gradual change to life, not just geology. Darwin argued that there could be no extinction without the origin of new species. Life forms on Earth, he argued, were constantly in competition for the limited resources of food, water, and shelter. Species went extinct because other species had qualities that made them superior at finding food and shelter and, ultimately, reproducing. By the same logic, new species must appear over time, either surviving because of their superior qualities or dying out. Darwin argued that the origin of species was an incredibly drawn-out process, lasting many thousands of years. No human being had ever witnessed the origin of a new species, because it took so long—thus explaining why Cuvier’s examination of fossilized cats didn’t necessarily disprove evolution.

Kolbert visits the Icelandic Museum of Natural History to learn about the great auk, an extinct bird that probably died out in the mid-19th century. At the Museum, she sees fossils belonging to the great auk, or Pinginius impennis. The great auk was a large bird, almost three feet tall, that resembled a penguin—it had tiny wings, and couldn’t fly. It once lived in places as different as Norway, Italy, and Florida (the region now known as Newfoundland was once full of great auks, too). Great auks were excellent swimmers, and spent most of their life in the water. However, human beings hunted great auks into extinction. In America, for example, Native American tribesmen and, later, European fisherman, used auks for food and fuel.

The final home of great auks was probably the Icelandic island of Eldey. Kolbert traveled there, where she saw huge numbers of gannets—long-necked, cream-colored birds. 150 years ago, fishermen regularly rowed out to the island, where they would encounter great auks. Rumor has it that in 1844, three fishermen rowed to Eldey, where they found the last two great auks on the planet. The fishermen chased the birds around the island, and eventually captured them. In the chase, they broke an auk egg that the two birds had been guarding. Instead of eating the two dead auks, the fishermen sold their catch to an Icelandic dealer, who in turn sold the birds’ remains to a naturalist. Fifteen years later, two naturalists named John Wooley and Alfred Newton went to Iceland to track down the great auk, only to realize that it had gone extinct. Newton spent the rest of his life campaigning for the preservation of sea birds, and eventually succeeded in lobbying for a bill to protect these creatures—one of the first wildlife protection laws in world history.

Around the same time that Newton and Wooley were returning from their journey to Iceland, Charles Darwin was publishing a revolutionary paper on the process of natural selection. Darwin’s ideas immediately impressed Newton, and later in life they became friends. Personally, Darwin had encountered the phenomenon of human-caused extinction during his time in the Galápagos Islands. In 1835, Darwin first encountered the Galápagos tortoises, and learned that their population was shrinking at an alarming rate, due to the whalers and fishermen who ate the tortoises. Less than ten years later—by which time Darwin was back in England, Galápagos tortoises had gone extinct. In his most famous book, The Origin of Species, Darwin notes that species become rare before they go extinct, and briefly alludes to human-caused extinction.

Although Darwin was clearly aware of human-caused extinction, he seems not to have found it a serious or troubling phenomenon. Darwin conceived of human beings as, fundamentally, subject to the same laws of natural selection as all other animals. He even recognized that human intelligence was just an evolutionary adaptation, similar to a lion’s claws or a finch’s beak. And yet, Darwin seemed not to understand that humans were unique among animals in one way: they were the only animals who caused other animals to go extinct. Furthermore, the fact that humans could cause other animals to suddenly go extinct suggested that Cuvier was right—cataclysmic events played a major role in extinction.