Re: Nando Explains Natural Selection to You!

hersheyh@xxxxxxxxxxx wrote:

> That means, of course, that an organism with a new *beneficial* variant
> phenotype (selection works on phenotype directly and genotype only
> indirectly) is not *guaranteed* success. And the effect is that the
> new mutant allele (we will assume dominantly) that causes the
> beneficial phenotype might go extinct (rather than go to fixation) by
> pure chance.

And such notions of pure chance are nonsense.

> In fact, it is possible to actually calculate this
> probability. Not surprisingly, the probability that a new *locally
> beneficial* allele (one that produces a better fit phenotype) will go
> to fixation is a function of the *selective advantage* of having the
> new *beneficial* allele relative to having the old wild-type or
> dominant allele.

It is a mistake to think that comparisons cause anything.

> This is in contrast to the probability of a new
> selectively neutral allele going to fixation, which is a function of
> the *size of the population*.
>
> In general, then, for small populations, chance alone may be more
> frequent cause for the fixation of a new allele (but, because the
> chance of a new mutation *occurring* in a small population is smaller,
> we tend to get a rate of neutral change over evolutionary time that is
> independent of population size and dependent on mutation rate). For
> larger populations, selective benefit (or lack thereof) will be a more
> important (more favorable) in determining allele presence.

And yet I remember evolutionary biologists say that evolution,
including developing of adaptations, mainly occurred in small isolated
populations, and can't much happen in large populations.

> That is, natural selection leads to optimization of organisms to the
> *local* conditions. Not teleologic optimization. Only optimization to
> a particular local set of conditions.

It is already teleological that you identify the workings of NS in view
of the result of optimal fitness.

You have to first answer the question why you separate scenario's as
enumerated previously, which are apparently one and the same process,
into separate theories.

Why is it that when the white moth goes extinct by pressure from the
black moth it is natural selection, and it's not natural selection when
the white moth goes extinct by other factors then a variant, or why is
it not natural selection when some new trees turn black and the all
black moth population spreads into the new environment of blackened
trees?

The answer you will find, is solely because of the way your interests
are organized, not the way nature is organized, because in nature it is
all clearly one and the same process.

regards,
Mohammad Nor Syamsu

.

Relevant Pages

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