Mutations ? (Re: D'Abrera on Science and Philosophy)

[John Grehan]

I thought the comments about religion and mysticism were interesting. In my
case the
traditional evolutionist claims and style of argumentation were hardly
convincing, and I
was an evolutionist by default (i.e it was the intellectual substrate
within which I did
science), but I had to find my own evidence that gave me an intellectual,
rather than reactionary,
view of evolution.

The result has been my support for less than most popular views of
evolution, but on the other
hand I am able to sympathize with creationist skepticism of orthodox
evolution. However,
where creationists stop is their general inability to recognize that there
is more to evolution than
just the Darwian centered framework of natural selection. In this respect
creationists seem
to share an interesting trait with orthodox evolutionists, the suppression
of alternatives that would otherwise muddy the ideological war.


>I think the mechanisms of evolution are not clear yet.
>Basically, spontaneous mutations or genomic recombinations will
>promote a high variability in a population, that will be
>filtered through natural (or sexual) selection.

Is this all there is to the origin of variation. What about molecular drive?

>If we look at a classical mullerian mimicry system, like the
>burnet moths (Zygaena) or the genus Heliconius, the whole system
>is convincing. As a monophyletic group, the ancestors of all
>species share the same potential of variability/polymorphism.
]
An important point - there was a concidence of structure within which natural
selection works.

>A slight genomic change in part of the population will be tested
>by natural selection (e.g. bird predation) and development of
>a discrete specific mate recognition system may isolate a new
>population without affecting the general protection against
>visual predation.
>Now if we look at mimicry systems that involve different orders
>(bugs-ants or beetles-hornets). It's very difficult to imagine how
>mutations may lead to the mimic habitus, providing that all
>intermediates

"Difficult to imagine" is itself a problematic statement. What is difficult
for one
is easy for another.


>Concerning DNA recombinations, I'm not a specialist but it seems
>to be a 'black box' explanation without concrete examples of
>-positive- acquisitions.
>
>The lack of positive effects of genomic modifications (observed or
>induced in the lab for 100 years) is probably the reason why
>so many people are not convinced by the classical approch of
>evolution.

I agree. perhaps labs are not the best way to look at evolution. And perhaps the
wrong kind of evolutionary framework is being applied.

>
>For my own, I think that these genomic modifications may explain
>the whole process to obtain an ant-like bug.

I agree with this comment, and believe that the spatial scale of real-world
biogeographic
events is important in providing the circumstances of when and how these changes
take place. I believe that insights into these processes are not yet well
understood.

My thr'pence woth this time

John Grehan