Jean-Baptiste Lamarck

Jean-Baptiste Lamarck (1744-1829), French botanist and invertebrate zoologist who formulated one of the earliest theories of evolution.

Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck, was born in Bazentin-le-Petit, France. Sent to a Jesuit school in Amiens, Lamarck received a classical education until 1759. That year, his father died, and Lamarck entered the military and began to study plants. In 1768 he left military service and studied medicine in Paris for four years, during which time he became interested in meteorology, chemistry, and shell collecting. At the same time, he wrote a work on his botanical observations, which French naturalist Georges Louis Buffon arranged to publish in 1779 as Flore françois (Plants of France). As a result of the book and his friendship with Buffon, Lamarck was elected to the Academy of Sciences. He became an associate botanist in 1783, but his most significant work was done when he began to work at the Jardin du Roi (King's Garden) in 1788. When the garden was reorganized in 1793, Lamarck's ideas helped to frame the structure of the new Museum of Natural History. Ironically, the reorganization resulted in removing Lamarck from botany and making him professor of insects and worms, a division he named invertebrate zoology.

While Lamarck's contributions to science include work in meteorology, botany, chemistry, geology, and paleontology, he is best known for his work in invertebrate zoology and his theoretical work on evolution. He published an impressive seven-volume work, Histoire naturelle des animaux sans vertèbres (Natural History of Animals without Backbones, 1815-1822).

Lamarck's theoretical observations on evolution, referred to as transformism or transmutation in the early 19th century, preceded his extensive observational work on invertebrates. With his colleagues, French naturalists Georges Cuvier and Geoffroy Saint-Hilaire, Lamarck accepted the view that animals in nature were arranged on one continuous scala naturae (natural scale). According to Lamarck, once nature formed life, the arrangement of all subsequent forms of life was the result of time and environment interacting with the organization of organic beings. From the simplest forms of life, more complex forms emerged naturally. These ideas were initially presented in Lamarck's major theoretical work, Philosophie zoologique (Zoological Philosophy, 1809), and he elaborated on them throughout his career. His final treatment of his hypothesis was included in his multi-volume work on invertebrates. Here, Lamarck explains his marche de la nature (scale of nature) as being controlled by three biological laws: environmental influence on organ development, change in body structure based on use and disuse of parts, and the inheritance of acquired characteristics. However, Lamarck's views were never clearly presented nor coherently argued; as a result, his ideas were not seriously entertained during his lifetime. His theory of evolution suffered at the hands of Cuvier, who championed his own ideas from a more powerful scientific and political position. Lamarck died with little scientific recognition of his work or his ideas. Not until the second half of the 19th century were Lamarck's ideas seriously considered again.