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

> 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.

With group replication of all the genes in the whole organism, when the
organism as a whole divides or otherwise reproduces, it's possible for
different brothers to suffer different mutations, causing differential
survival, such that some brothers do better than others, such that some
sets of brothers go extinct while others reproduce to larger numbers to
replace the lost brothers. If genes in one organism cooperate better
than genes in another, that could result in better survival and
reproduction for the former. Over time, natural selection favoring
cooperation can cause the average level of cooperation to increase.
What was originally a set of totally unrelated genes trapped in a
single organism forced to work together or die, eventually evolves to
become a set of co-evolved genes helping each other, else they wouldn't
have survived so long.

In the absense of any group replication (reproduction of the organism
as a whole), what was originally a bunch of unrelated replicators
trapped together, will *remain* a bunch of unrelated replicators, never
evolving any cooperation because there's no selection for cooperation
and against non-cooperation. So in the absense of reproduction of the
group as a whole, with no cooperation among the varioius
trapped-together replicators, an "organism" never comes into being in
the first place, it's always just a simple ecosystem of selfish
replicators, never any cooperation required to define an "organism".

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. Earth's
biosphere is *just* an ecosytem, and your proposed non-reproducing
thing is likewise *just* an ecosystem, unless at some time in the past
it *did* reproduce as a whole with group selection to encourage
cooperation.

> 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). It'd be every gene for
itself, every gene basically parasitical on the so-called organism as a
whole. Again I say you should just drop the word "organism" for such a
non-organism *only*-an-ecosystem.

> It could also be argued that the term "replicate" *must* refer to
> data - and not information - and that encrypted polymorphic computer
> viruses transmit information to their offspring without replicating
> it.

Perhaps my distinction of "gene" vs. "meme", according to whether
replication is of the physical substrate as well as the data pattern,
or only the data pattern mapped to any available substrate, would be
useful here. DNA replication is by "genes" because the actual chemical
species (A T C or G) are reproduced in the result, whereas virus on
computers is replicated by "memes" because only the information pattern
is imposed on the infected computer memory, replacing whatever was in
those same memory locations before, working just as well regardless of
whether the target memory is MOS or FET or whatever technology.

.

Relevant Pages

  • Re: Difference between random and non-random Natural Selection?
    ... Well what then is the intent with RM+NS - Random mutation and Natural ... building an organism; it is normally duplicated along with the organism ... during reproduction. ... "Natural Selection" means that the environment then ...
    (talk.origins)
  • Re: Difference between random and non-random Natural Selection?
    ... building an organism; it is normally duplicated along with the organism ... during reproduction. ... "Random Mutation" means that during the ... *ever* have any effect on reproductive success, then Natural Selection ...
    (talk.origins)
  • Re: Difference between random and non-random Natural Selection?
    ... building an organism; it is normally duplicated along with the organism ... during reproduction. ... "Random Mutation" means that during the ... *ever* have any effect on reproductive success, then Natural Selection ...
    (talk.origins)
  • Re: Cumulative fitness, Red Queens, and the interaction matrix
    ... > John, you are being obnoxious. ... Fitness has to be heritable to be selectable. ... >> 2) Did you mean you lump the reproduction of individual organisms ... >> (a number of reproductions reproduced by just the one parent organism) ...
    (sci.bio.evolution)
  • Re: OOL X - The origin of the RNA world.
    ... > on a global scale as a self-regulating homeostatic system. ... there's no way that natural selection could have evolved our particular ... > parasites - and come together to form a single large organism - the ... whether "more fit" means more cooperation among ...
    (sci.bio.evolution)
Loading