Re: Article: On the Origins of Chemical Biodefense

On Tue, 18 Oct 2005 00:56:20 -0400 (EDT),
William Morse <wdmorse@xxxxxxxxxxxx> wrote:
> lamoran@xxxxxxxxxxxxxxxxxxxxxxx (Larry Moran) wrote in news:diu8pu$7bb$1
> @darwin.ediacara.org:

[snip]

>> There is a controversy in the field of molecular evolution. Some
>> people, like me, believe that convergence explains many common
>> sequence motifs. We believe it's very unlikely that all traces
>> of sequence similarity could be lost in regions that must preserve
>> structural integrity while randomly changing all the amino acids
>> in order to wipe out sequence similarity. That just doesn't make
>> a lot of sense.
>
> It's very strange to hear Larry arguing for convergence - this is the
> adaptationist stance.

The adaptationist program tries to account for everything by invoking
natural selection. When you call someone an adaptationist you mean to
imply that they are going too far and they are ignoring other
possibilities.

Pluralists, as the name implies, do not deny that natural selection is
a common and important mechanism of evolution. It should not surprise you
to discover that a pluralist can invoke selection. That's what we do.

> Convergence on a common protein structure from diverse lineages over
> millions of years? Surely that cannot be due to neutral evolution - the
> odds against are astronomical.

Pluralists do not argue that everything has to evolve by random genetic
drift. That would be a very silly position to take. Did you really think
that's what I proposed, or is this sarcasm?



Larry Moran

.

Relevant Pages

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