Saturday, August 18, 2007
Baron Georges Léopold Chrétien Frédéric Dagobert Cuvier (August 23, 1769–May 13, 1832) was a French naturalist and zoologist. He was the elder brother of Frédéric Cuvier (1773–1838), also a naturalist. He was a major figure in scientific circles in Paris during the early 19th century, and was instrumental in establishing the fields of comparative anatomy and paleontology by comparing living animals with fossils. He is well known for establishing that extinction was a fact, being the most influential proponent of catastrophism in geology in the early 19th century, and opposing early evolutionary theories. His most famous work is the Règne animal distribué d'après son organisation (1817; translated into English as The Animal Kingdom). He died in Paris of cholera.
Life and scientific career
Scientific ideas and their impact
At the time Cuvier presented his 1796 paper on living and fossil elephants, it was still widely believed that no species of animal had ever become extinct, because God's creation had been perfect. Authorities such as Buffon had claimed that fossils found in Europe of animals such as the wooly rhinoceros and mammoth were remains of animals still living in the tropics (ie rhinoceros and elephants), which had shifted out of Europe and Asia as the earth became cooler. Cuvier's early work demonstrated conclusively that this was not the case.
Cuvier came to believe that most if not all the animal fossils he examined were remains of species that were now extinct. Near the end of his 1796 paper on living and fossil elephants he said:
All of these facts, consistent among themselves, and not opposed by any report, seem to me to prove the existence of a world previous to ours, destroyed by some kind of catastrophe.
This led Cuvier to become an active proponent of the geological school of thought called catastrophism that maintained that many of the geological features of the earth and the past history of life could be explained by catastrophic events that had caused the extinction of many species of animals. Over the course of his career Cuvier came to believe that there had not been a single catastrophe but several, resulting in a succession of different faunas. He wrote about these ideas many times, in particular he discussed them in great detail in the preliminary discourse (introduction) to a collection of his papers, Recherches sur les Ossemens Fossiles de Quadrupédes, on quadruped fossils published in 1812. The 'Preliminary Discourse' became very well known and unauthorized (and in the case of English not entirely accurate) translations were made into English, German and Italian. In 1826 Cuvier would publish a revised version under the name Discours sur les révolutions de la surface du globe.
After Cuvier's death the catastrophic school of geological thought lost ground to uniformitarianism, as championed by Charles Lyell and others, which claimed that the geological features of the earth were best explained by currently observable forces, such as erosion and volcanism, acting gradually over an extended period of time. However, the increasing interest in the topic of mass extinction starting in the late 20th century has led to a resurgence of interest among historians of science and other scholars in this aspect of Cuvier's work.
In 1808 Cuvier identified a fossil found in Maastricht as giant marine reptile, which he named mosasaurus. The following year he identified, working only from a drawing, a fossil found in Bavaria as a large flying reptile, which he named pterodactyl. Cuvier speculated that there had been a time when reptiles rather than mammals had been the dominant fauna. This speculation was confirmed over the next two decades by a series of spectacular finds, mostly by English geologists and fossil collectors, who found and desribed the first icthyosaurs, plesiosaurs, and dinosaurs.
Age of reptiles
In a 1798 paper on the fossil remains of an animal found in some plaster quarries near Paris Cuvier wrote:
Today comparative anatomy has reached such a point of perfection that, after inspecting a single bone, one can often determine the class, and sometimes even the genus of the animal to which it belonged, above all if that bone belonged to the head or the limbs. ... This is because the number, direction, and shape of the bones that compose each part of an animal's body are always in a necessary relation to all the other parts, in such a way that - up to a point - one can infer the whole from any one of them and vice versa.
This idea is sometimes referred to as 'Cuvier's principle of correlation of parts', and while Cuvier's description may somewhat exaggerate its power, the basic concept is central to comparative anatomy and paleontology.
Principle of correlation of parts
Cuvier was highly critical of evolutionary theories proposed by his contemporaries Lamarck and Geoffroy Saint-Hilaire. He was skeptical of the mechanisms of change that they proposed and his commitment to the principle of correlation of parts caused him to doubt that any mechanism could ever significantly modify any part of an animal in isolation from all the other parts, without rendering the animal unable to survive. In his Elegy of Lamarck, Cuvier noted that Lamarck's theory rested on two shaky assumptions — that a nervous fluid exists with the power to mold organs and that use and disuse can effect changes in an organism's body type:
"[Lamarck's evolution] rested on two arbitrary suppositions; the one, that it is the seminal vapor which organizes the embryo; the other, that efforts and desires may engender organs. A system established on such foundations may amuse the imagination of a poet; a metaphysician may derive from it an entirely new series of systems; but it cannot for a moment bear the examination of any one who has dissected a hand, a viscus, or even a feather."
He also pointed out that Napoleon's expedition to Egypt had retrieved animals mummified thousands of years previously that seemed no different from their modern counterparts.
Opposition to evolution
Chief scientific work
In 1798 Cuvier published his first independent work, the Tableau élémentaire de l'Histoire naturelle des animaux, which was an abridgment of his course of lectures at the École du Pantheon, and may be regarded as the foundation and first statement of his natural classification of the animal kingdom.
In 1800 he published the Leçons d'anatomie comparée, assisted by A. M. C. Duméril for the first two volumes and Georges Louis Duvernoy for the three later ones.
On comparative anatomy and classification
Cuvier's papers on the Mollusca began appearing as early as 1792, but most of his memoirs on this branch were published in the Annales du museum between 1802 and 1815; they were subsequently collected as Mémoires pour servir de l'histoire et a l'anatomie des mollusques, published in one volume at Paris in 1817.
In this field Cuvier published a long list of memoirs, partly relating to the bones of extinct animals, and partly detailing the results of observations on the skeletons of living animals, specially examined with a view of throwing light upon the structure and affinities of the fossil forms.
Among living forms he published papers relating to the osteology of the Rhinoceros Indicus, the tapir, Hyrax Capensis, the hippopotamus, the sloths, the manatee, etc.
He produced an even larger body of work on fossils, dealing with the extinct mammals of the Eocene beds of Montmartre, the fossil species of hippopotamus, a marsupial (which he called Didelphys gypsorum), the Megalonyx, the Megatherium, the cave-hyena, the pterodactyl, the extinct species of rhinoceros, the cave bear, the mastodon, the extinct species of elephant, fossil species of manatee and seals, fossil forms of crocodilians, chelonians, fishes, birds, etc. The department of palaeontology dealing with the Mammalia may be said to have been essentially created and established by Cuvier.
The results of Cuvier's principal palaeontological and geological investigations were ultimately given to the world in the form of two separate works: Recherches sur les ossements fossiles de quadrupedes (Paris, 1812; later editions in 1821 and 1825); and Discours sur les revolutions de la surface du globe (Paris, 1825). In this latter work he expounded a scientific theory of Catastrophism.
On palaeontology and osteology
None of Cuvier's works attained a higher reputation than his Règne Animal distribué d'après son Organisation pour servir de base à l'Histoire Naturelle des Animaux et d'Introduction à l'Anatomie Comparée, the first edition of which appeared in four octavo volumes in 1817, and the second in five volumes in 1829–1830. In this classic work Cuvier embodied the results of the whole of his previous researches on the structure of living and fossil animals. The whole of the work was his own, with the exception of the section on Insecta, in which he was assisted by his friend Latreille. It was translated into English many times, often with substantial notes and supplementary material updating the book in accordance with the expansion of knowledge.
The Animal Kingdom
Apart from his own original investigations in zoology and paleontology Cuvier carried out a vast amount of work as perpetual secretary of the National Institute, and as an official connected with public education generally; and much of this work appeared ultimately in a published form. Thus, in 1808 he was placed by Napoleon upon the council of the Imperial University, and in this capacity he presided (in the years 1809, 1811 and 1813) over commissions charged to examine the state of the higher educational establishments in the districts beyond the Alps and the Rhine which had been annexed to France, and to report upon the means by which these could be affiliated with the central university. Three separate reports on this subject were published by him.
In his capacity, again, of perpetual secretary of the Institute, he not only prepared a number of éloges historiques on deceased members of the Academy of Sciences, but he was the author of a number of reports on the history of the physical and natural sciences, the most important of these being the Rapport historique sur le progrès des sciences physiques depuis 1789, published in 1810.
Prior to the fall of Napoleon (1814) he had been admitted to the council of state, and his position remained unaffected by the restoration of the Bourbons. He was elected chancellor of the university, in which capacity he acted as interim president of the council of public instruction, whilst he also, as a Lutheran, superintended the faculty of Protestant theology. In 1819 he was appointed president of the committee of the interior, and retained the office until his death.
In 1826 he was made grand officer of the Legion of Honour; and in 1831 he was raised by Louis Philippe to the rank of peer of France, and was subsequently appointed president of the council of state. Member of the Doctrinaires, he was nominated to the ministry of the interior in the beginning of 1832.
Animals named after Cuvier
Posted by iamyrfans at 10:37 AM