Chapters 2-3 Summary

Scientists didn’t consider the concept of extinction until the late 18th century. French zoologist Georges Cuvier was the first to consider it. He believed mastodon fossils were from a “lost species.” First, Cuvier believed a single catastrophe wiped out most species and then later hypothesized several extinction events. His theory that the mastodon became extinct 13,000 years ago by a flood was nearly correct. However, Kolbert says, humans are likely to blame for overhunting them into extinction.

But Cuvier did not embrace the idea of evolution. He believed species didn’t change. It was French zoologist Jean-Baptiste Lamarck who first proposed an early theory of evolution, claiming that animals’ bodies change to adapt over a long period of time.

Scientists who believed in sudden mass extinction events were coined “catastrophists.” “Uniformitarians,” like Scottish geologist Charles Lyell, believed that changes in the landscape slowly effected species change, leading to eventual extinction. Today, scientists understand that both types of extinction exist.

British naturalist Charles Darwin developed the theory of natural selection. According to Darwin, species that adapt better produce more offspring and pass these adaptations on to their offspring. Further, Darwin believed a link existed between the origin of a new species and the extinction of an existing species. A species with superior qualities, in foraging and reproduction for example, will survive, while a species less adapted for survival will die out. During Darwin’s life, scientists observed the extinction of the great auk (a flightless seabird). Humans killed auks for food and fish bait. The book’s author, Elizabeth Kolbert, visits Iceland, the last known site of two live great auks that were killed while guarding an egg in 1844. Years later, naturalists went in search of auks, only to realize they had gone extinct.

Chapters 2-3 Analysis

In Chapter 2, Kolbert explores the process of scientific discovery, describing it as a living process with a curved, rather than linear, track. She points out that Cuvier’s theories about extinction were often ridiculed but that today he is seen as a visionary.

Kolbert reveals that even Cuvier didn’t completely understand evolution and that scientific thought and discoveries continue to refine humans’ understanding of the process. Her text demonstrates the scientific process by which ideas merge with evidence to become theories. Through examination of the many fossils discovered by 18th-century explorers, many theories emerged, including the idea that the mastodon fossils might belong to an as-yet-undiscovered species. But eventually scientists began to piece together evidence that undeniably supported extinction. And, as a true scientist, Cuvier was never satisfied with his understanding. He continued seeking “new” extinct species and proved his theories to a skeptical public.

In Chapter 3, Kolbert addresses Darwin’s influence on extinction theories. Not only did Darwin’s ideas on natural selection radically shift the evolution narrative, but they inextricably connected it to extinction. Darwin’s belief in the slow process of evolution would mean that a person should not expect to witness a species go extinct during a lifetime. Yet, the example of the great auk both demonstrates his incorrectness about how long extinction takes and affirms the role of one species in causing another’s extinction—in this case, humans killing off the last of the great auks.