In Nature’s Ghosts, Mark V. Barrow, Jr. presents a study of two centuries of changing attitudes of American naturalists toward the concept of species extinction and of the role of the scientific community (encompassing both professional scientists and amateur naturalists) in efforts to prevent extinctions. Barrow begins with the Revolutionary War generation, focusing especially on Thomas Jefferson, and ends with the passage of the 1973 Endangered Species Act, with a brief glance forward to the rise of the field of biodiversity in the last quarter of the twentieth century.
For Jefferson, an ardent naturalist as well as a statesman, species extinction was simply not possible. Like most of his eighteenth century contemporaries, he believed that nature was orderly and static. There was no room in his universe for creatures to completely disappear. For him, the fossilized bones discovered on the North American continent were evidence that, somewhere on the continent, great beasts such as the mammoth and the giant sloth still roamed. One of the charges that Jefferson gave Meriwether Lewis and William Clark on their great expedition across North America to the Pacific Ocean from 1803 to 1805 was to look out for living specimens of these animals.
Barrow points out that, even as Jefferson confidently anticipated that the unexplored American West would prove to be the home of the living remnants of these species, Georges Cuvier of the Paris National Museum of Natural History was systematically describing a variety of fossilized animals and arguing that these museum specimens represented species that were extinct. By the end of the first decade of the nineteenth century, it was evident to most professional naturalists that some species had disappeared from the earth. A generation later, in 1832, in utter contrast to Jefferson’s confidence in the survival of all of nature’s creations, the British geologist Charles Lyell could, without generating controversy in the scientific community, consider extinction as a routine part of the natural world.
Reinforcing the paleontological evidence of extinctions taking place many years earlier, by the mid-nineteenth century naturalists could point to three examples of extinction within human memory. The disappearance of great flightless birds from the islands where they once dwelled demonstrated that human action could and did lead to species extinction. The dodo on Mauritius, the moa in New Zealand, and the great auk of the islands of the North Atlantic were all wiped out by human action. Naturalists recognized that humans could destroy species directly, through overhunting, and indirectly, through habitat destruction and the introduction of predators.
Confronting this harsh reality, naturalists developed seven justifications of their efforts to preserve species. The first was the aesthetic pleasure provided by plants and animals. In direct contrast to this was the utilitarian argument that humans could lose useful and important services and products uniquely provided by endangered plants and animals. These services and products ranged from the immense quantity of destructive pests eaten by certain birds to potential, but still unknown, botanical cancer cures. Third, naturalists argued for the need to preserve the ecosystems. To lose any component of an ecosystem could endanger the stability of the entire system. The fourth argument was both somewhat sentimental and an acknowledgment of the centrality of evolution in science. As end products of a long, and in some cases complex, evolutionary path, each species was seen as a sort of monument to evolution. All such monuments, the naturalists claimed, should be preserved. Preventing the loss of key aspects of American identityunique native plants and animalswas a fifth justification. The American bison and the bald eagle were in this category of distinctively American creatures. The sixth justification was a desire to preserve species for the befit of...
(The entire section is 1,555 words.)