Re: OOL X - The origin of the RNA world.

Robert Maas, see http://tinyurl.com/uh3t <rem642b@xxxxxxxxx> wrote or quoted:
> > From: Tim Tyler <tim@xxxxxxxxxxx>

> > for there to be selection there have to be alternatives to select
> > between.
>
> Yes. I'm not aware of anyone disagreeing with that.
>
> > I'm talking more about the possibility of a single large organism,
> > which doesn't reproduce, and instead maintains itself.
>
> That's not possible, except as the last surviving member of an
> endangered species which previously evolved by reproduction and
> differential survival among brothers.

So it *is* possible.

> Accordingly it is best not to call it an "organism" in the first place.
> This is the mistake Lovelock made, and Gould and Margulis bought into,
> sigh, acting like the whole Earth's ecosystem is an "organism" despite
> the fact it never reproduced as a whole hence never could evolve the
> level of cooperation needed to make it an actual organism.

Lovelock made no such mistake. His theis was that the planet acted
on a global scale as a self-regulating homeostatic system.

Your criticsim of Lovelock's ideas is the same as Dawkins' criticism of
them - but you are both taking the original idea far to literally.

> Earth's biosphere is *just* an ecosytem, and your proposed
> non-reproducing thing is likewise *just* an ecosystem, [...]

In a nutshell, the idea is that - in the far future - living organisms may
coordinate their cooperative activity on a universal scale. They might
dispense with their endosymbionts, symbionts and parasites - and come
together to form a single large organism - the last living thing.

> unless at some time in the past it *did* reproduce as a whole with
> group selection to encourage cooperation.

Reciprocal altruism and kin selection are responsible for most
cooperation in nature. Group selection appears to be of low relevance.

> > It could be argued that a single large organism would - in
> > practice - have to keep backup copies of its genome in order
> > to avoid a mutational meltdown - and would have to identify
> > errors, copy information between copies - and after a long
> > period of time all the information in each copy would have
> > been replaced - and that time period could be christened as
> > being one generation of replication.
>
> There's no natural-selection mechanism to cause any such mechanism to
> ever evolve in the first place (unless it is that last surviving member
> of a species that reproduced in the past).

No natural selection - but the topic was *evolution* - and
evolution != natural selection.

Such an organism would be subject to self-directed evolution.

Rather than evolve under natural selection, it would become what
it wanted to become.
--
__________
|im |yler http://timtyler.org/ tim@xxxxxxxxxxx Remove lock to reply.

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