Jean-Baptiste Lamarck

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Jean-Baptiste Lamarck (1744–1829) was a French naturalist who proposed one of the first coherent scientific theories of biological evolution, decades before Charles Darwin, though the specific mechanism he proposed for it was later shown to be incorrect. Trained initially for the military and then in medicine and botany, he built a career at Paris's Royal Botanical Garden and later at the Museum of Natural History, where he was placed in charge of the collections of insects and worms -- a category he reorganized into a rigorous new classification system for what he named "invertebrates," a term he coined to distinguish these animals systematically from vertebrates for the first time.

Lamarck's most significant and lasting idea, laid out fully in his Zoological Philosophy (1809), was that species are not fixed but change gradually over time, transforming from simpler to more complex forms in response to environment and use. To explain how such change could be passed on, he proposed what is now called the inheritance of acquired characteristics: the idea that traits an organism developed or strengthened through use during its lifetime -- and, conversely, lost through disuse -- could be passed to its offspring, a mechanism he illustrated with the now-famous, if oversimplified, example of giraffes stretching their necks to reach high leaves. This specific inheritance mechanism was rejected by later genetics, which showed that acquired traits generally cannot be transmitted through reproduction, and it is this rejected mechanism, rather than his broader case for evolution itself, that the term "Lamarckism" has come to designate, often unfairly overshadowing his real contribution.

Lamarck also did foundational classificatory work on invertebrate zoology that remained influential independent of his evolutionary theorizing, and some historians credit him, alongside the German naturalist Gottfried Reinhold Treviranus, with independently introducing the term "biology" around 1802 to describe the unified scientific study of living things, though this credit is disputed and Treviranus is more often named as its sole originator. Lamarck spent his final years in poverty and blindness, dictating his last work to his daughter, and his evolutionary ideas were largely dismissed by the scientific establishment of his time, including by the powerful naturalist Georges Cuvier, before being revisited with more nuance after Darwin's work made evolution itself a serious subject of debate.

Written by Epoch Voices. Not the figure’s own words.