Re: Chain reactions and sparks in the origin of life


"Tim Tyler" <seemysig@xxxxxxxxxxxxxx> wrote in message news:fqo5r9$6ks$1@xxxxxxxxxxxxxxxxxxxxxx
Guy wrote:

In other words, the metabolisms-first view envisions the
prior existence of a physical potential (e.g., a thermal
and/or macromolecular gradient) that pulled dynamic
metabolic (chemical) structures into existence. [...]

The thrust here seems to be that something cannot be called
a 'fluke' if it is the inevitable result of deterministic thermodynamic
forces. Of course, Tom believes his own scenarios are fluke-free
precisely because he sees them as the inevitable response to
environmental forces. But I'm not sure this is the right way
to think about things. There are at least three different senses
in which the word 'fluke' might be appropriate, even though
the result is inevitable given physical law.

The first sense is that the key event (such as the ignition of
an autocatalytic cycle due to the appearance of a cycle
constituent or such as the chance appearance of a self-replicating
polymer sequence) might inevitably happen sometime over a
period of (say) a million years. But it still has to be called
a 'fluke', in some sense, when it actually does happen 600,000
years (say) after the clock started.

The second sense is that the key event might be inevitable
on some kinds of planets but practically impossible on most
planets. So, the fact that our planet (or even any planet in
our galaxy) is appropriate for the origin of life might be called
a fluke.

And thirdly, notice that there are hundreds of thousands of
deterministic and inevitable chemical events in this universe
and that most of them have absolutely nothing to do with the
origin of life. It may well be a 'fluke' that the laws of our
universe happen to be set up such that abiogenesis is inevitable.

Now, you can perhaps invoke the 'anthropic' principle to
make these 'flukish' events seem quite unsurprising. Fine.
But if you do that, the word 'fluke' should hold no terrors.
There is then no particular philosophical reason to avoid
OOL stories that include 'flukes' or 'just-so-stories' in their
plot outline.

In my preferred OOL scenarios, the key events were
'flukes' in the first sense and possibly in the second and
third senses as well. And I don't see any reason why
I should feel ashamed of this.

The metabolism-first vs genes-first terminology never
made much sense to me - since any living system would
need a both a metabolism and a heritable information
store.

The terminology makes sense to me. Many 'genes-first'
scenarios (especially Cairns-Smith, but also RNA-first)
contemplate an original metabolism which is so impoverished
as to hardly deserve to be called a metabolism. Heterotrophic
accumulation of 'building blocks' from the environment and
their assembly or condensation is not really 'metabolism' in
my view. To have 'metabolism', ISTM that you at least have
to make some of the 'building blocks' yourself, or at least
to activate the blocks with some kind of 'high energy bonds'.

Similarly, while I agree that some kind of heritable information
has to exist to have 'life', I wouldn't say that the information
has to be 'genetic' in the Schroedinger or Watson/Crick sense.
That is, the information does not need to involve information-bearing
molecules or 'alphabets'. It can be more subtle: topological, for
example; or based on whether particular autocatalytic cycles
are in the 'ignited' state. Any attractor of a dynamical system
is potentially a form of information inheritance which is not
'genetic' in the usual senses.

.

Relevant Pages

  • Re: Chain reactions and sparks in the origin of life
    ... a 'fluke' if it is the inevitable result of deterministic thermodynamic ... That means that your key event must either happen more than once which ... may be necessary for life. ... contemplate an original metabolism which is so impoverished ...
    (sci.bio.evolution)
  • Re: Logic Gives But One Choice On OOL. Can any find another?
    ... metabolism, which is a "metabolism first" viewpoint. ... if not adapted immediately, we need another fluke. ... because the underlying chaotic chemical dynamics are ... fire (new origins of life), because it is already being tapped by the ...
    (sci.bio.evolution)
  • Re: Logic Gives But One Choice On OOL. Can any find another?
    ... metabolism, which is a "metabolism first" viewpoint. ... it immediately adapted to the environment, or is it destroyed in that ... if not adapted immediately, we need another fluke. ... Do chemicals want to get to you - to metabolism, ...
    (sci.bio.evolution)
  • Re: Logic Gives But One Choice On OOL. Can any find another?
    ... you feel the nucleotide problem can be solved but I do not agree. ... metabolism, which is a "metabolism first" viewpoint. ... "Metabolism first' is a fluke chemical event. ... You could argue that a convection cell is initially spawned by ...
    (sci.bio.evolution)
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