Re: Two of a kind.

NashtOn <nana@xxxxx> wrote in
news:Hj0ag.7988$A26.202660@xxxxxxxxxxxxxxxxxxxxxxx:


Nice.
This makes sense if you *believe* that the driving force behind
evolution is mutation of genes.

The driving force behind evolution is the many types of selection and
drift. Mutations are an initial source of variation. No need to
'believe' that it is so, it can be observed in the lab and in nature. As
for selection being a driving force, once you acknowledge allele
variation all else simply becomes a numbers game. For a simple
understanding, look at the Hardy-Weinberg Equalibrium equation.

It would also make sense if the
majority of species reproduce *asexually*.

Why would you choose 'majority of species' as your criterion rather than
most successful (most numerous, longest history, etc..)?

The most successful (and most plentiful) of all organisms, the
bacterium, uses both asexual (fission) and sexual reproduction.

But hold on, doesn't sexual
reproduction increase the probability of survival? Then why haven't
the species that reproduce asexually evolved into sexually reproducing
species?

Is this the 'Why are there still monkeys?' argument? Surely you don't
believe evolution is teleological.

Isn't it important to have the advantage of sexual
reproduction for these species? Is their environment not competitive?
Is it possible that mutations aren't as important to "evolution" as
previously thought?

Why would you persist in believing such an overly simplistic idea? You
know (or I hope you do) that there is nothing inevitable or teleological
about evolution but that changes to an organism rely not just on the
mutation but on the specific environment, which is comprised of more
than just geology and meteorology but includes population size,
female/male sexual preference, local competitors for food, local
predators, disease, and countless other factors, and, here comes the
main point, the *initial state* of the organism.


Now, explain this to me, Windy. If point mutations in genes can be
reversed, why can't "evolution" occur in reverse, if the deleterious
effects of your precious mutations are diminished via sexual (haploid)
reproduction?


How very 'deterministic' of you NashtOn.

Again this is very simplistic.

You seem to assume that an individual and by extrapolation the entire
population experiences *one* mutation at a time in an orderly (forgive
me) order. At any given time there will be multiple mutations active in
a population and more that, while not active at that time, may later
become active depending on changes to the environment. Selection does
not operate on all mutations equally nor does it operate on all
mutations evenly through time.

If we take one individual that has a deleterious mutation and remove him
from the 'gene pool' then all that will happen is *stasis* with regards
to that mutation, not regression. For a point mutation to be reversed it
must not be 'removed' as in the first case but be *mutated* back to its
prior state. This is possible but is highly unlikely. For mutations that
affect multiple nuceotides/codon/genes, even complete chromosomes, the
likelihood of an exact reversal is even less likely.

For a population to regress a number of *exact* mutations would have to
occur in an *exact* locus in an *exact* order (especially if a prior
mutation such as gene duplication is overlain by a more recent but
different mutation). For that to happen the initial state of not just
one individual but all individuals in the population for the *now* and
for the *past* target state must be known (figuratively speaking). In
addition to the state of the population, all initial states within the
environment would need to be known. In systems such as evolution, both
the past and the future quickly become chaotic.

Future evolutionary paths can not be predicted nor can existing paths be
reversed.

BTW, Windy's point was that 'deleterious' mutations are more quickly
removed from the population. That says little if anything about neutral
and/or beneficial mutations.

--
Gary Bohn

Science rationally modifies a theory to fit evidence, creationism
emotionally modifies evidence to fit a specific interpretation of the
bible.

.

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