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Name: Matt D Carter
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Question:
Why do organisms mutate?



Replies:
Not sure if you mean "how" or "how come." If the second, then it's because this ensures a variation in the characteristics of the offspring. Each new generation of cheetahs includes a few who can run faster (but need to sleep more, say) and a few who can't run as fast (but who can go longer without food), and a lot who are pretty much the same as their parents. Then the environment does its job, and whoever isn't good enough at getting food dies and has no kids. The genes for the abilities that don't do the job get deleted from the species, and the average ability of the cheetah to get food rises. By and by they become real good at it. You still need to preserve the ability to adapt to the environment at this stage because the environment changes. Evolution is what makes species improve, and the two key parts of it are mutation and natural selection (the deletion process; it's not "natural" in the sense of "normal" but "natural" in the sense of "done by Nature.") Now if you mean "how," then the answer I think is usually assumed to be deliberate errors in duplicating DNA by the cell. The machinery for copying DNA is just set up so that every now and then it copies the recipe for a new cell as "1 egg and 1 eye of newt" instead of "1 egg and 1 teaspoon baking soda." X-rays and certain chemicals increase the rate of mutation, but I'm not sure this is significant in general.

Christopher Grayce



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