The Sixth Extinction: Chapter 2

     In Chapter 2, Kolbert introduces Georges Cuvier who studied the fossils of the American mastodon and concluded that all such creatures died out in the distant past. During the 18th century, French scientists debated the origins of the mastodon remains. Some argued that the bones actually belonged to two or three creatures, including a hippopotamus. Other scientists proposed that the bones belonged to an entirely new animal called the American elephant.On April 4, 1796, Cuvier delivered a lecture in which he discussed the Mastodon remains from Ohio, as well as the remains of a similar creature that had been discovered in Russia. He proposed that the two sets of remains belonged to two new animal species, neither one of which had survived. Cuvier called these kinds of creatures "lost creatures". His theory of lost creatures on his own research into the Ohio and Russia fossils, as well as animal remains from Argentina. Finding evidence of other lost creatures among those remains, Cuvier concluded that they must have belonged to vanished species. His lectures at the Museum popularized the theory of extinction. Later on in the book Cuvier and Jean-Baptiste, have a debate over mutation and evolution. Cuvier concluded that it was impossible for animals to mutate or evolve over time, since even the tiniest changes in an animal’s body would prevent it from surviving. Lamarck proposed that animals could slowly change their own bodies over time. For example, he argued that giraffe’s necks were long because giraffes had spent millennia reaching for leaves in tall trees. Cuvier had determined that some species went extinct over time. But he still needed an explanation for why this happened. At first, he proposed that one great disaster in the distant past had wiped out species simultaneously. Later, after fossil hunters had identified distinct “layers” of fossils, he changed his mind and argued that there had been multiple cataclysmic events that led to multiple extinctions.

     (R) The themes that I seemed that connected the most with this chapter was science constantly changes the way we understand the world and science is a method of learning more about the world. In the beginning of the chapter it said that during his time Cuvier was often mocked for his theories, but now, centuries later many people are looking up to him because he understood many issues and topics that nobody could during his time. Also in the chapter Cuvier made many conclusions about extinction. He first based his findings on his analysis of all available evidence and then went on to argue that animals went extinct in the past. On page 44 it states, “Later, as his list of extinct species grew, his position changed. There had, he decided, been multiple cataclysms. Life on Earth has often been disturbed by terrible events… Living organisms without number have been the victims of these catastrophes.” Cuvier’s theories of extinction didn’t allow him to see the theories of evolution. He noticed that animals’ bodies were perfectly adjusted to their diet and habitat. Based on his observations, Cuvier concluded that it was impossible for animals to mutate or evolve over time, since even the tiniest changes in an animal’s body would prevent it from surviving. Although Cuvier had been debunked many times he was able to prove that the mastodon went extinct 13,000 years ago. As Cuvier was able to research more and learn more about science and animals and was able to debunk old notions, he was able to learn many facts and was able to prove his original theory right.

                                                           By: Mousumi Dhar