miércoles, 19 de mayo de 2010

Jean-Baptiste Lamarck

Hola clase,

I sometimes read this webcomic about literary, scientific, and historical subjects, and recently this came up, and I thought of our Darwin class (making Darwin more available to the general public):So I decided to research the topic.
Lamarck's ideas, of course, are said to have been a great influence on Darwin, who mentioned his 'use and disuse' theory (usually in the context of disuse and vestigial organs), and thought it was grand that he brought to peoples' attention "the probability of all change in the organic... world, being the result of law, not miraculous interposition."
But Lamarck apparently did have quite the argument with well-respected paleontologist Georges Cuvier, back in the day (the early 1800's). Lamarck was one of the first to come up with a "coherent" theory of modification over time, with the mechanisms being 1) a complicating force driving species up a "ladder" of development, and 2) adaptation to local environments, leading to distinct forms of organisms. As he said it,
"frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, and gives it a power proportional to the length of time it has been so used; while the permanent disuse of any organ imperceptibly weakens and deteriorates it, and progressively diminishes its functional capacity, until it finally disappears"
"these [modifications] are preserved by reproduction to the new individuals which arise, provided that the acquired modifications are common to both sexes"

The problem was that Cuvier was positive that species didn't change, having found fossils that just appeared as they were, stayed that way for long periods of time, and then disappeared. I think (but I'm not sure) that this is just a lack of actual fossil evidence, especially given that Cuvier thought that every single large animal had been discovered by his time. But Cuvier also thought that geology and biology were subject to catastrophism. So of course he got in arguments with Lamarck, saying that one part of an animal couldn't change gradually in isolation from the other parts (which is of course the argument still in use today against evolution, as we have discussed). The argument in the webcomic is basically entirely true to fact; Cuvier looked at mummified specimens and said that they were exactly the same as modern animals; Lamarck countered that evolution happened too slowly to see over only a few thousand years; and Cuvier replied that since nothing happens over a short time, saying that allowing more time was just a convenient defense for a silly theory.

In Cuvier's defense, he was an early proponent of the theory of extinction-- previously, people thought that all creatures were perfect as created by God, and thus wouldn't die out. He was also, on occasion, hilarious:
"When the French Academy was preparing its first dictionary, it defined "crab" as, "A small red fish which walks backwards." This definition was sent with a number of others to the naturalist Cuvier for his approval. The scientist wrote back, "Your definition, gentlemen, would be perfect, only for three exceptions. The crab is not a fish, it is not red and it does not walk backwards."

Despite this, Cuvier was still a major jerk, as it turns out. He gave a eulogy for Lamarck that was totally backhanded:
"...we have conceived it to be our duty, while bestowing the commendation they deserve on the great and useful works which science owes to him, likewise to give prominence to such of his productions in which too great indulgence of a lively imagination has led to results of a more questionable kind, and to indicate, as far as we can, the cause, or, if it may be so expressed, the genealogy of his deviations."

So basically, it looks like my webcomic is both highly entertaining and educational. If you'd like to learn more about history, literature, historical figures, and the like, maybe go have a look:


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