Yesterday, August 1, was the anniversary of the birthday of Jean-Baptiste Pierre Antoine de Monet. Who? Perhaps a relative of the artist Monet? No, someone better-known by his title, the Chevalier de Lamarck. Lamarck was, as far as I can tell, the first major evolutionary biologist. He not only argued that life had evolved, but he put forward a proposed mechanism that would explain why living things became well-adapted. It involved two forces: a proposed inherent complexifying force, and the effects of use and disuse of organs. That would lead to adaptation, if these changes were passed on to the next generation by inheritance of acquired characters. That kind of inheritance was assumed by everyone to exist – Lamarck did not invent it – but we now know better.
If he had lived, Lamarck would now be the ripe old age of 274. Lamarck and Lamarckism have good Wikipedia pages, so I will not try to explain his thought further here. But below the fold, a few additional comments on his work:
- Lamarck would have been a major biologist even if he had never argued for evolution. He was a great figure in invertebrate systematics, clarifying the classification of invertebrates greatly. For that matter, he invented the word "invertebrate".
- Lamarck's inherent complexifying force is less well-known than his use/disuse effect. To us today, it seems rather mystical, as physics has not found any such force. Although there were Lamarckians for 100 years after Lamarck, they tended to play down the mysterious complexifying force, which seems to have embarrassed them.
- Lamarck's comments on human evolution are somewhat vague, but he points clearly to the "orang of Angola" as the closest relative to humans. It is clear from the species name that he uses, troglodytes, that this is the chimpanzee.
- Epigenetic effects are often referred to as "Lamarckian". They are not, as they involve no effect of use and disuse.
I have tried to commemorate Lamarck’s birth yearly here – this year I was delayed by not being able to figure out quickly enough how to post here. Many thanks to my colleague Alan Cohn, a distinguished invertebrate systematist, who first turned me on to the achievement and importance of Lamarck. Happy birthday, Jean-Baptiste!