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|Baron Georges Cuvier
[kyoo vyA'] prover of extinction and proponent of the theory of catastrophism
Georges Léopold Chrétien Frédéric Dagobert Cuvier was born at Montbéliard, France, on August 23, 1769. He studied at the Carolinian Academy in Stuttgart from 1784 to 1788, then took a position as tutor to a noble family in Normandy. It was while working in this position that he began to make his reputation as a naturalist. In 1795, a paper on mollusks he wrote came to the attention of Geoffrey Saint-Hilaire, who invited Cuvier to a post at the newly reformed National Museum of Natural History in Paris. Cuvier continued his zoological research at the Museum over many years, emerging as one of the most considerable scientific intellects of his generation. By 1805 he had completed his Lesson in Comparative Anatomy, and in 1810 he published his Historical Report on the Progress of the Sciences. Important as an educationalist, Cuvier helped to set up several French provincial universities. He organized the collection of a vast range of fossils (including the pterodactyl, which he discovered and named), and began their systematic study. By the time of his death he had been knighted and made a Baron and a Peer of France.
Proof of Extinction
In 1796, Cuvier read a paper before the National Institute in which he analyzed skeletal remains of Indian and African elephants, as well as mammoth fossils and a fossil skeleton known at that time as the "Ohio animal." Cuvier's analysis established for the first time the fact that African and Indian elephants were different species and that mammoths were not the same species as either African or Indian elephants and therefore must be extinct. He further stated that the "Ohio animal" represented another extinct species that was even more different from living elephants than mammoths were. In 1806 he returned to the "Ohio animal" in another paper and gave it the name mastodon.
In his second paper, also delivered in 1796, Cuvier described and analyzed a large skeleton found in Paraguay, which he named megatherium. He concluded that this skeleton represented yet another extinct animal and, by comparing its skull with living species of tree-dwelling sloth, that it was a kind of ground dwelling giant sloth.
Cuvier noticed that the deeper down in the earth's crust a specimen came from, the more remote it seemed from existing animal forms. His contemporary, Jean-Baptiste Lamarck, developed a basic theory of evolution, which he published in 1809 and which partly anticipated by 50 years the theory of the origin of species of Charles Darwin. Cuvier rejected any such notion, however. He saw organisms as integrated wholes, in which each part's form and function were integrated into the entire body. No part could be modified without impairing this functional integration, so any change in an organism's anatomy would have rendered it unable to survive.
To account for the chronological sequence of his fossils Cuvier looked to the theory of catastrophism, which had been the common scientific belief since the 17th century. Cuvier believed that the Earth was immensely old, and that for most of its history conditions had been more or less like those of the present. However, periodic catastrophes had befallen the Earth, each one of which wiped out a number of species. Each successive catastrophe had the effect of advancing the complexity of life since it was obvious that more recent creatures were advances on the ones that went before.
Principle of Correlation of Parts
The principle of correlation of parts was particularly important in the case of collections of fossil bones. At right is an anatomical study of a living hippopotamus, taken from Cuvier's Researches on Fossil Bones (1824). Cuvier believed that if the shape of each bone was studied in functional terms, in relation to the rest of the body, it should be possible to reconstruct correctly a whole animal from its parts. However, the functional significance and relationship of many anatomical parts was not known. Cuvier therefore, had to rely more on his wide knowledge of the anatomy of living animals, than on the principle of functional coordination.
The implication of Cuvier's principle was that all the anatomical structure and individual organs of an animal are they way they are and "collaborate" with each other, so as to adapt the animal to "the conditions of its existence." It thus differed from other prevailing theories of the time which held that an animal's anatomy governed its mode of living. Below is a painting of the reconstruction of the dodo at the National Museum of Natural History, where Cuvier was curator of anatomical material. Although the dodo became extinct in about 1681, reconstruction was still possible from surviving skeletons and old descriptions.
Classification of the Animal Kingdom
Cuvier's insistence on the functional integration of organisms led him to classify animals into four "embranchements": Articulata (arthropods and segmented worms), Mollusca (which at the time meant all other soft, bilaterally symmetrical invertebrates), Radiata (cnidarians and echinoderms), and Vertebrata (all the higher animals). For Cuvier, these embranchements were fundamentally different from each other and could not be connected by any evolutionary transformation. Any similarities between organisms were due to common functions, not to common ancestry -- function determines form, form does not determine function. Though they had to be discarded in time, Cuvier's classifications were transitional between old ideas and the new ones which would finally undermine the theory of a scale of creation. His book, The Animal Kingdom, Distributed According to Its Organization (1817) was a decisive improvement on the system devised by Linnaeus.
Georges Cuvier died of cholera in the first epidemic to hit Paris, on May 13, 1832.
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