[lbo-talk] the epigenenome

ravi ravi at platosbeard.org
Fri May 15 09:00:39 PDT 2009


On May 15, 2009, at 11:45 AM, Matthias Wasser wrote:
> On Fri, May 15, 2009 at 11:18 AM, ravi <ravi at platosbeard.org> wrote:
>>
>>
>> I believe we are talking about mutations. A mutation of a gene
>> occurs in an
>> individual. If that individual does not reproduce -- which is in
>> fact the
>> majority case, since most mutations are regressive and decrease the
>> reproductive success of the carrier -- that mutation is lost.
>
> Irrelevant nitpick: most mutations have no effect on fitness
> whatsoever.
>

That's an irrelevant nitpick. Substitute neutral and remove "majority" if that makes you happy. It leaves my point intact.


> I don't believe anybody (except perhaps Dawkins, & al.) is disputing
> the
> individual level of selection. But it would seem weird to deny that
> species
> is a level of selection in evolution, which is just the change in
> allele
> frequencies over time. If changes in the environment lead to humans,
> wheat,
> and cattle increasing in prevalence relative to trees, beavers, and
> star-bellied snitches, this is a meaningful change, even if it does
> not
> result in or arise from evolution within those species, ie,
> individual-level
> selection.

I think you have answered your own objection i.e., mutation occurs at the individual. Other kinds and levels of selection, as you correctly outline, are feasible, but are not the result of mutations (again, as you correctly outline). But note that you write "species is a level of selection in evolution". It can be a level of selection, but as you note, there is no evolution going on here, in the classical sense. Again, the notion of evolution has to be extended. Which is entirely possible and a worthy exercise.


> This level of selection operates on a different logic -
> Lamarckian and, ignoring HGT, asexual - and so I think it's useful
> to treat
> it as more than simply the aggregate of individual-level selection;

Absolutely right.

--ravi



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