Jean-Baptiste Lamarck

Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck, started as a soldier: he fought Prussia in the Seven Years' War, earned a battlefield commission for bravery, then took an injury in 1766 that ended the military career and opened another. Posted to Monaco, he'd grown curious about the natural world; he retired to study medicine, but botany took hold. His three-volume Flore françoise in 1778 won him a seat in the French Academy of Sciences the next year. By 1788 he held the Chair of Botany at the Jardin des Plantes; when the Revolution refounded the institution as the Muséum national d'Histoire naturelle in 1793, Lamarck shifted to zoology. He coined "invertebrates," classified them in his 1801 Système des animaux sans vertèbres, and in 1802 became one of the first to use "biology" in its modern sense. His 1809 Philosophie zoologique laid out the first cohesive theory of evolution: a complexifying force pushing organisms up a ladder, an environmental force adapting them through use and disuse of traits. The mechanism didn't survive scrutiny, but the vision did - and biologists still argue whether epigenetics has circled part of the way back to him.