CONTRASTING LAMARCK AND DARWIN

In the video of the professor George Wolfe, he explained the difference between the theory of evolution of Lamarck and the Darwin’s one. Ha said that the biologists usually asked themselves why there are changes in the organisms instead of just asking what a change is.

Lamarck had two tenets (principios) for evolution:

use and disuse

the inheritance of acquire characteristics.

That means that if an organism didn’t use an organ it will disappear by time or of they used a lot an organ, or needed better characteristics they would grow or change for better little by little, if one giraffe need a longer neck, it will stretch it until it grows a little and that difference will pass to their offspring that will stretch their necks to grow them more, until they have the perfect longitude.

Darwin had another idea which had some steps:

1-overpopulation: first there were a lot of animal of the same specie.

2-variation: some of those animals, that will be for example giraffes, will have a longer neck, as some of us have a long nose, or curly hair.

3-compete: as there were a los of animals, they compete for survival, for example for food and the giraffes with the longer necks will have easier to take the leaves of the higher trees.

4-survival of fittest: the best animals, in this case the giraffes with the longer neck, will have better possibilities to survive as they can take more food, so giraffes with long necks will be fittest.

5-reproduction: as giraffes with a long neck are the fittest they will have more possibilities to reproduce and have offspring, because females choose the best ones for breeding. Then their characteristic will be passed to offspring and finally most of the giraffes will have long necks.

But this don’t happens because giraffes think they need a long neck and they try to stretch it, it just happens because they are lucky and they have a characteristic that will be better, as it could have been worse for them. That is the difference between Lamarck’s and Darwin’s theories, the first happens because they need it, and the second just randomly and through genes.

Finally George Wolfe asked a question about what will Lamarck think about the brains of woodpeckers and their protection to the hits in the trees, and what will think Darwin.

🙂

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