Lamarck

Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck (1744–1829) was a French naturalist whose work helped shape early ideas about evolution. He is best known for proposing one of the first coherent mechanisms of evolutionary change, often called Lamarckism or transformism.

Born in Bazentin, Picardy, Lamarck studied medicine and natural history in Paris and spent much of his career at the Jardin des Plantes and the Muséum national d’Histoire naturelle, where he held a chair in invertebrate zoology. He conducted extensive observations across a wide range of organisms, including many invertebrates, and published influential writings on biology and classification.

Lamarck argued that organisms undergo gradual transformation driven by an inherent plasticity and by interactions with their environment. In his view, features acquired through use or disuse could be inherited by offspring, a mechanism he described as the inheritance of acquired characteristics. He also proposed a vital force or internal tendency that guided the progressive organization and complexity of living beings. He emphasized the role of the environment in shaping organisms and their traits, presenting a dynamic view of life’s development.

His most famous work, Philosophie Zoologique (1809), laid out these ideas with extensive descriptions of invertebrates and other organisms, illustrating how life might adapt to different conditions. Lamarck’s ideas influenced early evolutionary thought and contributed to the later debate that culminated in Darwinian natural selection. While genetics has since shown that acquired traits are not generally inherited, Lamarck’s emphasis on environmental interaction and the organism–environment relationship remains a notable milestone in the history of biology.