Lamarck, Jean Baptiste Pierre Antoine de Monet, Chevalier de (1744–1829), a French naturalist. His Philosophie Zoologique (1809) presents an early theory of evolution. Lamarck believed that acquired characteristics could be inherited. Thus the long neck of the giraffe, according to Lamarck, was developed by an effort, running through thousands of years, to reach the foliage of trees. His theory met with little acceptance during Lamarck's lifetime and is now generally disproved.

Lamarck coined the word “invertebrate” to describe animals without backbones, the subject of most of his research. He is considered the founder of invertebrate paleontology (the study of invertebrate fossils).

Lamarck, the son of a nobleman, was educated for the clergy at the Jesuit College of Amiens. He later joined the army and served in the Seven Years' War. When an injury forced him to leave the military, he went to Paris to study medicine and botany. In 1778 Lamarck was admitted to the Academy of Sciences for devising a new method of classifying plants. From 1788 to 1818 he was a professor at the Royal Garden, first in botany, and after 1793 in zoology.