Question about Evolution

[BrianSoddingBoru4]

Mutation is the raw material, natural selection acts upon mutation.

Suppose a fish is hatched with a mutation that provides ever-so-slightly better oxygen extraction.  The mutation itself is thoroughly random, but it provides a benefit that may make that particular fish better able to adapt and to breed than some of its cousins.  Since mutations occur at the genetic level, this new trait will be passed on to some of the mutated fish's young.  The fish that inherit this trait will be 'fitter' and more likely to survive and breed.  The mutation (random) has thus been selected for (non-random).

Good question.

Boru

Good explanation, except for the "ever-so-slightly" part. Such a mutation would likely be lost in the shuffle.

That's not really how it works, though. If even marginally beneficial mutations were 'lost in the shuffle', there would be no natural selection at all. Since natural selection is an observed fact, then even small mutations are preserved (beneficial ones, at least).

Boru