Lamarck, Jean-Baptiste

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Editors: John Merriman and Jay Winter
Date: 2006
Europe 1789-1914: Encyclopedia of the Age of Industry and Empire
Publisher: Charles Scribner's Sons
Document Type: Biography
Pages: 3
Content Level: (Level 5)
Lexile Measure: 1410L

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About this Person
Born: August 01, 1744 in Bazentin, France
Died: December 18, 1829 in Paris, France
Nationality: French
Occupation: Naturalist
Other Names: Lamarck, Jean-Baptiste-Pierre-Antoine de Monet de; Lamarck, Chevalier de; Lamarck, Jean-Baptiste; Monet, Jean Baptiste Pierre Antoine de; Lamarck, Jean Baptiste Pierre
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LAMARCK, JEAN-BAPTISTE

LAMARCK, JEAN-BAPTISTE (1744–1829), one of the world's leading zoologists and also the first biologist to offer a full-scale theory of organic evolution.

Jean-Baptiste Lamarck was born in the small village of Bazentin in the Picardie region of France. The youngest child in a large family of the French lesser nobility, he was destined by his parents to be a priest. After his father died, he decided to pursue a military career instead. He served in the army from 1761 until an injury in 1768 forced him to resign. He subsequently made his way to Paris, where he successively worked in a bank, attended medical school, and finally concluded that what he wanted to do most was be a botanist.

Lamarck first gained visibility as a botanist by announcing to the botanists of the Jardin du Roi (the King's garden) that he could produce a guide to the plants of France superior to any guide then in existence. His project attracted the attention of the institution's director, Georges Louis Leclerc de Buffon (1707–1788), who arranged to have Lamarck's Flore française (Flora of France) published in 1778 at government expense. Buffon also championed Lamarck's election to the Academy of Sciences and gave him the official title of "correspondent" of the Jardin du Roi.

Lamarck worked productively as a botanist through the 1780s. In 1789, the year after Buffon's death, he secured from Buffon's successor at the Jardin du Roi a salaried position, that of "botanist of the king and keeper of the king's herbaria." During the French Revolution, however, royal associations became liabilities. In 1793 the Jardin du Roi was reconstituted as the National Museum of Natural History. In the reshuffling of staff at the institution, Lamarck lost his position as a botanist butPage 1302  |  Top of Article received a whole new responsibility, the professorship of "worms, insects, and microscopic animals." His expertise in this area at the time was limited to what he knew as the result of being a collector of shells. Nevertheless, as he worked over the next two decades with the museum's burgeoning collections, he became the leading authority on that part of the animal kingdom he himself designated as the "invertebrates."

Lamarck was not content, however, to restrict his attention to the classification of the invertebrates. From the mid-1770s onward he nursed broad speculative notions about chemistry and meteorology, and in the 1790s he began publishing on these subjects, generally to the detriment of his reputation, since leaders in the scientific community were inclined to dismiss his formulations as examples of uncritical "system-building."

Lamarck first endorsed the idea of species mutability in 1800 in a lecture he delivered to his class on invertebrate zoology at the museum. Precisely what inspired his belief in organic mutability is uncertain, but one issue that concerned him at this time was the relation between fossil and living forms of shellfish. Confronted with the idea of species extinction, but reluctant to believe that extinction had occurred on a broad scale, he chose to think that living creatures had been gradually transformed over time in response to climatic changes on the earth's surface. He thereby took a position directly contrary to that of his colleague, Georges Cuvier (1769–1832), who opposed the idea of organic transformation while arguing that great catastrophes in the earth's past had wiped out entire assemblages of large land animals. Lamarck advanced his transformist theory at length in his 1809 Philosophie zoologique (Zoological Philosophy) and again in 1815 in his great treatise on invertebrate classification, Histoire naturelle des animaux sans vertèbres (Natural history of the invertebrates).

Lamarck's zoological theorizing encompassed much more than an explanation of how species change. He sought to account for the nature and origin of life, the production of the different forms of animal organization, and the diverse faculties to which these different forms of organization give rise. His explanation of the successive production of living forms began with the claim that the simplest forms of plant and animal life were produced by spontaneous generation. He believed these forms were then successively modified by two very different causes. The first, which he named "the power of life," was responsible for the general tendency toward increased complexity seen in the plant and animal classes alike. The second was the modifying influence of the environment, which tended to interfere with the general tendency toward increased complexity.

Lamarck's explanation of the influence of the environment on animal forms depended on the idea with which his name is now most frequently associated, "the inheritance of acquired characteristics." Changes in the environment, he claimed, led animals to develop new habits, causing them to use some organs more and other organs less. The more frequent use of an organ tended to strengthen and develop it, the less frequent use of an organ tended to weaken it and cause it to atrophy. Bodily changes thus acquired were then passed on to the next generation (provided, in the case of sexually reproducing organisms, that both parents had undergone the same changes). Habits maintained over many generations, together with the inheritance of acquired characteristics, thereby led to such diverse structural features as the long neck and forelegs of the giraffe and the rudimentary eyes of the mole.

The belief that acquired characteristics could be inherited was a commonplace in Lamarck's day. What was not accepted, however, was Lamarck's claim that such modifications could go so far as to result in new species. It was only after the 1859 publication of Origin of Species by Charles Darwin (1809–1882) that the idea of organic evolution gained widespread acceptance in the scientific community. It was only then, furthermore, that the inheritance of acquired characteristics came to be identified as a distinctively "Lamarckian" idea, in contrast to the Darwinian theory of natural selection. The reality of the inheritance of acquired characteristics was not seriously challenged until the 1880s. It continued to have adherents among biologists well into the twentieth century, but support for it waned as the experimental and other evidence advanced on its behalf was shown to be susceptible to other interpretations.

Lamarck died in 1829, blind and impoverished. In the twenty-first century his name is associated primarily with the now-discredited idea of thePage 1303  |  Top of Article inheritance of acquired characteristics, but he deserves to be remembered more generally for his contributions to botanical and zoological systematics and for having been the first writer to set forth a detailed, comprehensive theory of organic evolution.

BIBLIOGRAPHY

Burkhardt, Richard W., Jr. The Spirit of System: Lamarck and Evolutionary Biology. Cambridge, Mass., 1995.

Corsi, Pietro. The Age of Lamarck: Evolutionary Theories in France, 1790–1830. Translated by Jonathon Mandelbaum. Berkeley, Calif., 1988.

Lamarck, Jean Baptiste. Zoological Philosophy: An Exposition with Regard to the Natural History of Animals. Translated by Hugh Elliot. Chicago, 1984.

RICHARD W. BURKHARDT JR.

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Gale Document Number: GALE|CX3446900455