Question about Evolution

[Ignorant]

Couldn't a case be made for at least some 'moments' of "punctuated equilibrium"?

Could it not be mostly tiny strokes over lots of time, with isolated episodes of large strokes happening very quickly?

[deleteduser12345]

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.

Except such mutations haven't been lost in the shuffle quite many times.

[FatAndFaithless]

Also important to remember that evolution deals in mutations across populations, not individuals.

[LastPoet]

Also notice that mutations aren't all good. Most do not help, even hinder the beings lives in the environment. Those individuals with 'bad' mutations breed much less than the others. Those get selected out. Over time and in populations.

[Doubting Thomas]

On the other hand, if a mutation causes a deer to be colored "Hunter's orange" he's a deader, because that's like a red cape to a fighting bull for hunters. 

[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

[John V]

That's not really how it works, though.

We don't know how it really works, but mathematical models have been created. IIRC Haldane was the first, and came up with a probability of fixation of 2s, where s is the reproductive advantage given by the mutation. More complex models for different population dynamics have been produced since. Genetic drift can cause beneficial mutations to be lost, and deleterious mutations to fix, despite the effects of natural selection. That isn't a creationist position.

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).

WTF? Saying that small beneficial mutations can be lost in the shuffle doesn't preclude natural selection, as:
- Not all are lost in the shuffle
- That doesn't preclude the possibility of mutations with larger benefit

I mean, really, your logic there is just a WTF moment.

[BrianSoddingBoru4]

That's not really how it works, though.

We don't know how it really works, but mathematical models have been created. IIRC Haldane was the first, and came up with a probability of fixation of 2s, where s is the reproductive advantage given by the mutation. More complex models for different population dynamics have been produced since. Genetic drift can cause beneficial mutations to be lost, and deleterious mutations to fix, despite the effects of natural selection. That isn't a creationist position.

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).

WTF? Saying that small beneficial mutations can be lost in the shuffle doesn't preclude natural selection, as:
- Not all are lost in the shuffle
- That doesn't preclude the possibility of mutations with larger benefit

I mean, really, your logic there is just a WTF moment.

Maybe we're talking at odds about what we mean by 'small' and 'large' mutations. Probably my own fault, as I'm used to talking with creationists who look upon 'mutation' as the sudden appearance, for example, of a fully functioning eye.

By 'marginal' I mean a mutation which imparts a small - but still measurable - advantage to a particular organism. Sorry for the confusion.

Boru

[Whateverist]

Couldn't a case be made for at least some 'moments' of "punctuated equilibrium"?

Could it not be mostly tiny strokes over lots of time, with isolated episodes of large strokes happening very quickly?

In fact some tiny stokes have big time effects.  When you look at how embryos develop it seems as if one possible mutation is simply to change the number of iterations of a set of limbs.  That could make a pretty noticeable difference in a single generation.  But I imagine the odds of such a mutation being advantageous are probably even thinner since an optimal number of limbs has probably already been achieved.