Jean Lamark was a French botanist and invertebrate zoologist who formulated one of the earliest theories of evolution. In 1768 he wrote a book on his botanical observations, which French naturalist Georges Louis Buffon arranged to publish in 1779 as Flore fran ois (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.

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, Natural History of Animals without Backbones. Lamarck's theoretical observations on evolution, referred to in the early 19th century as transformism or transmutation, preceded his extensive observational work on invertebrates. With his colleagues, Lamarck accepted the view that animals in nature were arranged on one continuous 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, Zoological Philosophy, 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 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.