Sun 1 Feb, 2004 09:40 am
According to Lamarck, evolution occurs because organisms can inherit traits which have been acquired by their ancestors. For example, giraffes find themselves in a changing environment in which they can only survive by eating leaves high up on trees. So, they stretch their necks to reach the leaves and this stretching and the desire to stretch gets passed on to later generations. As a result, a species of animal which originally had short necks evolved into a species with long necks.
Natural selection explains the long necks of the giraffes as a result of the workings of nature which allowed the species to feed off of the leaves which grow high on trees rather than graze as short-legged, short necked animals are prone to do. There was no purposive behavior which was a response to the environment which was then passed on to later generations. There was simply an environment which included trees with leaves up high and that was a favorable food source to long-legged, long-necked animals such as the giraffe. In fact, according to natural selection, if that were the only food source available, only animals with long- necks, or animals which can climb or fly, would survive. All others would become extinct. There is no plan here, divine or otherwise, according to natural selection. Furthermore, there is nothing special signified by the fact that a species has survived. Survival of the fittest means only that those who have survived were fit to survive. It doesn't mean that those who survive are superior to those species which don't. They've survived because they were fit to adapt to their environment, e.g., they had long necks when there was a good supply of food readily available high up in the trees and there were no other catastrophic disadvantages to their height. For example, if a species got so tall that it became impossible to mate, it would become extinct. Or, if the only food source on high happened to have a substance in it which rendered giraffes sterile, there would be no more giraffes, no matter how hard they tried to will themselves potent.
So those weights I hang on my member aren't going to benefit my son, eh?
Dys, I forwarded your post to a woman I know who lectures on evolution at the University of New Mexico. I've signed up to take some classes this spring, which will include her lecture. She has a degree in Zoology and is alarmed at the political inroads the creationists are making in the education system.
I was always very unhappy wiv me short li'l neck - and wished that Lamarck had proven to be correct - or that I lived in the USSR, where, I gather, he was, for a long time - with generations of tail-less mice to prove it - although evolution now appears to be running the other way even there...
However - I am now seeing all my lovely swan-necked friends getting that unpleasant scraggy, red look, while I, and a few other ducks (as opposed to swans) still have the necks - more or less - we grew up with!
Did I digress?
Lots of mallards and canadian geese on the little stretch of river that still flows today. A couple of some other kind of goose I don't recognize there, too. Clearly a male and a female, with no others of their kind in the immediate vicinity. Pioneers, I guess.
There's a lot of it going on, Dys.
Somehow though I think it possible that societies sometimes evolve through a "Lamarkian" system.
This would seem to involve an intelligence and a goal system which although uncommon is not unheard of.
Might make a good thread. Perhaps thats what you are trying to do
Hope springs eternal
In all fairness to Lamarck, there was some peculiarity about the mating rituals of the salamanders (or was it newts? or frogs?) that he was observing that his theory explained quite nicely. Something about spurs on the forelegs of the male, but my memory is dim. The poor bastard just chose a bad model system.
I didnt mean to sound dissmissive. On the contrary i was laughing at dogs statement. Dys-your sumup of evolution is quite elegant and needs no further embellishment . Its just that profound and that unremarkable. Environment bats last. i think Ive said that so many times Im beginning to sound senile
Don't genes mutate rather routinely? I learned they did, way back when, something about 1 in a million.. And when they do, sometimes the changes are manifest in ways that help, say, a frog along the way, or... not. The froggy with the better leap survives to have tadpoles, or some such, but the mutation was random/routine.
yeh, osso, mutation is a mechanism that can account for the variability in species.BUT its the environment that selects the individual.
genetic mutation is, however, onlyone of a bunch of mechanisms. i like what Gould said in his last book before he died.
"genes are the bookkeeping of evolution, the record of its happening, not the cause ." again elegant .
Yes, it is elegant. I can't myself recite the other mechanisms in selection, off hand anyway (not disagreeing, I just don't know them).
Re: Lamarck vs Darwin
According to Lamarck, evolution occurs because... Natural selection explains...
Is there a question implied, or a point? I'm sorry, but if so, I'm missing it.
yep, thats it, and why not, hes earned it.