Evolution

[Guest bgjyd834]

Was lamarckian inheritance hypothesis wrong? he said the giraffe's long next develop over generations when its parents keep on stretch their neck to reach for high leaves. but then as we know, an individual's phenotype may change as a person develop large muscle after muscle training. but a child of muscle-bound parent is not born muscle-bound.offspring inherit genes, but not parents phenotypic changes. Does this mean Lamarck was wrong?

 

so if he was wrong. what traits goes to just change in phenotype and what goes to change in genes. how is it decided. for example, the fishes wants to catch prey on land, in theory of evolution, legs were slowly grown over generations.

 

and am i correct to say that when the first fishes feel the need to grow legs to catch prey on land, its genetic material had changed? if so why does it take so many generation to grow legs instead of the next generation?

[Cap'n Refsmmat]

Was lamarckian inheritance hypothesis wrong? he said the giraffe's long next develop over generations when its parents keep on stretch their neck to reach for high leaves. but then as we know, an individual's phenotype may change as a person develop large muscle after muscle training. but a child of muscle-bound parent is not born muscle-bound.offspring inherit genes, but not parents phenotypic changes. Does this mean Lamarck was wrong?

Yes, he was wrong.

 

so if he was wrong. what traits goes to just change in phenotype and what goes to change in genes. how is it decided. for example, the fishes wants to catch prey on land, in theory of evolution, legs were slowly grown over generations.

 

and am i correct to say that when the first fishes feel the need to grow legs to catch prey on land, its genetic material had changed? if so why does it take so many generation to grow legs instead of the next generation?

I think you don't quite understand how evolution works.

 

A legless fish does not decide one day "gee, legs would be handy". Evolution works on random mutations. That is, a fish has children fish, one of which has a random genetic mutation that makes it have leg-like things. That fish survives to have more child fish which also have leg-like things, and the legged fish do well, since they can get up on the beach. Then, one of the legged fish hatches a child with a mutation that gives it slightly more advanced legs, and so on.

 

That is to say, the change in genes occurs between generations. Those children with useful mutations survive, and those with harmful mutations die.

 

The animals have no control over the direction of their evolution -- it is random. Natural selection operates on whatever mutations naturally occu.

[Zarnaxus]

Are you correct to say that when you feel the need to grow wings, your child will have them?

 

 

[Ringer]

I would never say such a thing, and no it is not true.

[Marat]

You have to be careful saying that "Lamarckian inheritance is wrong," since the real Lamarck whom historians of science know is not the cardboard villain of evolution that textbooks make him out to be. In fact he stated many theories which look quite Darwinian.

[CharonY]

Lamarck and Darwin were not on opposite ends. Darwin was not sure which was the true mode of inheritance, his main contribution is the introduction of natural selection. He did not specify precisely the mode of inheritance. In fact, he did state that Lamarckian inheritance could also have played a role in that system. An apt comparison would be Mendel vs Lamarck.

And who the heck thinks Lamarck is a villain of any sort? Hyperbole much?

Edited April 15, 2011 by CharonY