"tinyurl.com/uh3t"  wrote in message
news:cnjpei$2j5q$1{at}darwin.ediacara.org...
> C> If it was the ancestor of life, it had to be able to mutate.
>
> R> I semi-disagree. Eventually it would of course need to somehow mutate,
> R> but it could survive for millions of years without mutating yet.
>
> > From: an588{at}freenet.carleton.ca (Catherine Woodgold)
> > What do you mean, semi-disagree?  Either it mutated or it didn't.
> > The passage of millions of years before the mutation ocurred
> > don't change my argument.
>
> It depends on semantics, how you define words. Mutation isn't a
> capability, something a replicator is able to do, rather it's a
> susceptability, something a replicator isn't able to prevent. [snip]

I semi-disagree ;-)

What we are interested in here is *heritable* mutation.  That strikes me
as a capability, rather than a susceptibility.

But I agree that there was probably SOMETHING that was "biological" enough
that I would call it "life" that existed for thousands of years and went
through considerable evolution before the first true kind of heritable
mutation arose.  The evolution was not due to natural selection as a
neo-Darwinist understands it, but it was probably Darwinnian evolution in
some broad sense.  There was a sort of "gradualism" to this evolution, and
there was a kind of "common descent".  There was probably even
"survival of the
fittest" in some sense.  There may have been several different
"species"
of self-reproducing sludge extant at any one time, with different sludge
species thriving in different niches.  There just was not (yet) heritable
variation.

If Catherine prefers not to call this stuff - whatever it was - "life",
well then she is in good company.

But, if you have a kind of sludge composed of ten chemicals catalyzing
each others formation, and this gets replaced in part of its habitat by
a new eleven component sludge consisting of nine of the original chemicals
plus two new ones, then I don't think that there is anything wrong with
saying that the ten-component sludge is ancestral to the eleven-component
sludge.  And if this is then replaced by a twelve-component sludge where
the twelveth component is a nucleic acid capable of true heritable variation,
then I don't see anything wrong with saying that the non-living (by Catherine's
definition) sludge was ancestral to the living sludge.
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