Lamarck, Jean-Baptiste

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Lamarck, Jean-Baptiste (1744-1829): French, Zoologist.

Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck, was the major pre-Darwinian theorist on evolution and the developer of invertebrate science. He was born to a military family on 1 August 1744 in Bazentin-le-Petit, France. After brief theological studies at Amiens, Lamarck entered the Army, serving heroically in battle until an injury compelled him to leave the service in 1768. He worked as a bank clerk while studying botany and chemistry. He also tutored the son of scientist Buffon, George-Louis Leclerc, Comte de, who became Lamarck’s mentor. With Buffon’s help, Lamarck published a book on French plants and gained election to the Academy of Sciences.

Starting out as a professor of botany, Lamarck became keeper of the Jardin du Roi, the royal garden, in 1788. He then helped set up the National Museum of Natural History, which had chairs for twelve professors. Increasingly interested in animal science, Lamarck was appointed professor in the Division of Insects and Worms, considered the lowliest branch in Linnaeus, Carolus’s system of zoological classification. Coining the term “invertebrates,” Lamarck recognized ten classes of animals without spines, instead of just insects and worms. His lifelong work on invertebrates culminated in the multivolume landmark work Natural History of Animals without Vertebrae, completed in 1822. But despite these accomplishments, Lamarck is better known for his controversial theory of evolution.

Lamarck’s studies of fossil records resulted in his determining that all life is related and constitutes a scala naturae, or natural scale, which progresses throughout time in a marche de la nature, or natural progress. Every group of animals flows into other groups, forming a continuous parade of life on earth. Rejecting the popular Biblical-based notion that the earth was of relatively recent creation, Lamarck supposed that millions of years of evolution had brought life from the simplest organisms up through man. And he posited that environmental changes stimulated the evolutionary changes in the species.

Unfortunately for Lamarck, he also hypothesized that acquired characteristics are passed along from generation to generation. For example, he speculated about the giraffe that by stretching its neck in quest of high leaves, an individual giraffe becomes longer-necked and then passes this characteristic onto its subsequent offspring. Lamarck’s eminent colleagues Geoffroy Saint-Hilaire and Georges Cuvier expressed the majority view that there is no scientific basis for the notion of inherited acquired characteristics. In 1861, Charles Darwin’s On the Origin of Species offered the alternative idea that Natural Selection, taking advantage of inborn characteristics, was evolution’s main mechanism, not the inheritance of acquired characteristics. However, Darwin praised Lamarck for popularizing the concept of evolution and correctly emphasizing the role of the environment in stimulating change in species.

Lamarck’s theories eventually found favor with twentieth-century Marxist ideologues in the Soviet Union, but modern findings in genetics have largely rebuffed neo-Lamarckian attempts to discredit Darwinism. Lamarck is today appreciated primarily as the principal founder of the field of organic evolution.

Further Reading:

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

Dianna Rivers

Lamar University