in article ck4bni$2h7o$1{at}darwin.ediacara.org, Fabrizio J. Bonsignore at
fbonsignore{at}beethoven.com wrote on 10/7/04 2:16 PM:

> TomHendricks474{at}cs.com wrote in message
> news:...
>> Some say life 'emerged'. Then through
>> the first replicator adapted to the environment
>> it was in.
>> But that supposes a 'grace' period during which
>> the environment did not in any way hinder
>> the replicator, until it had the needed time
>> to adapt to it's environment.
>> 
>> There was no 'grace' period. And any scenario
>> that allows for one is making a mistake IMO.
>> 
>> Comment?
> 
> There were several replicators but we descend from the only one that
> kept adaptaing from the beginning, either by chance or superiority.

Like so much in the OOL debate, this strikes me as unjustified arm-waiving.
My own opinion is that there must have been an enormous number of
spontaneously generated replicators (say trillions), and they may still be
spontaneously generating today.  I know of no study attempting to address
this issue, let alone evidence that spontaneous generation of replicators
does not happen in the modern world.  I also have no idea how to approach
the question of spontaneous replicator emergence in today's world, so I
readily admit that this is raw speculation.  I find it implausible that
replicators may have only emerged "several" times, because the chance of
avoiding extinction by replicating lineages of naked molecules formed
without the benefit of historical natural selection would have been
extraordinarily small on a per lineage basis.

My opinion also differs from that implied (I think) in the sentence above in
terms of the lineage sorting that led to the monophyly  of life on earth.  I
suspect that life may well have been polyphyletic for a very long time (say
a billion years), before all extant replicators could trace their ancestry
to a single replicator that had emerged without replicating ancestors.

To avoid misleading interpretations of my opinion on this issue, please note
that my comments were confined to molecular replicators and were not
intended to be about cellular life.  My opinions about the emergence of
cellular life on earth are similar in spirit, although I would expect the
numbers and the lineage sorting period to be much shorter.

Cheers,

Guy
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