Pedro -- Pleas post this for me. Thanks.
STAN
for <fis@listas.unizar.es>; Sun, 5 Nov 2006 15:15:37 -0500 (EST)
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>Date: Sun, 5 Nov 2006 17:21:35 -0500
>To: fis@listas.unizar.es
>From: "Stanley N. Salthe" <ssalthe@binghamton.edu>
>Subject: Re: [Fis] Response to Stan
>
>Replying to Richard --
>
>>Stan,
>>Your response hit the mark for me.� I find your assertion about the
>>primacy of the cell compelling in many respects, concisely stated,
too.� I
>>suppose Margulis & Sagan would agree with you. Cells, however,
are not
>>unique to biological systems.� I need to mull this over for a while,
and
>>maybe read their book. But there is one thing that, to my mind,
competes
>>with the cell for the title of biological primacy; it's the gene.� I
would
>>abandon this POV if I could understand how natural selection or any
other
>>known means of evolution allowed a cell to evolve a digitally
"symbolic"
>>(i.e., non-stereochemical) language with a geometrically precise
>>dictionary (e.g., GAU �> aspartic acid).�
> SS: Of course, the origin of the genetic system is arguably the most
>outstanding problem facing natural science. It seems that, other than the
>(to me) unconvincing RNA World idea, there is no compelling model of it.
>The RNA First model rests on the fact that some RNAs have catalytic
>ability. The big problem with it is that (as far as I know) there have
not
>yet been found natural conditions under which nucleic acids will form
>spontaneously. Without this, any RNA first model of the origin of life
>walks on crutches. This situation contrasts with that for other molecular
>constituents of living systems, for all of which conditions have been
found
>that promote their formation. Linear proteins require RNA templates, but
>branched proteinoids, which believably could have been their ancestors,
>have been formed spontaneously. As you imply, it is known that proteinoid
>microspheres can carry out all the major functions of cells, and so we
know
>that these do not require genetic information to occur. As well, fossil
>objects not distinguishable from these microspheres have been found in
>rocks predating traces of living systems. The most reasonable model of
>Life's origin at present seems to me to be that liquid crystalline
micelles
>gave rise to some kind of proteinid microspheres, and -- here s the
problem
>-- these somehow came to acquire what we know as the genetic system.
>
>>How can cells do this�when Crick's central dogma (another biological
law?)
>>prohibits them from writing or rewriting their own genes, which
themselves
>>amount to linear scripts of "pure digital information"
(Dawkins)?�
> SS: Of course, we do know of reverse transcriptase, but not of
>reverse translation. This has not stopped some folks ( Eva Jablonka,
>Steele) from making models of this kind of thing. I suppose their models
>are as good as the RNA Word models.
>
>>The only other time in natural history that I know of where
amalgamations
>>of cells evolved a digitally symbolic language was when humans did it
>>about 10,000 years ago.� (This assumes, of course, that�signals and
>>songs�of insects, birds, and other social species are not digitally
>>symbolic.)
>>So the mystery for me is how living cells evolved a digital language
to
>>manage its own structural affairs.� How can a molecular analog
dictate
>>digital script?�
> SS: There have been some ideas (under 'origin of the genetic code')
>about how certain nucleic acid triplets could have spontaneously
associated
>with particular amino acids, but I think this has been shown for very few
>of such couplets.
>
>>I know of no scientific principle that allows for ANY analogous
entity in
>>nature, save humans, to store its structural information digitally on
a
>>specific kind of molecular template.� And why only ONE kind of
molecule?�
>>Since I can't find my answer in a hierarchical context, I've looked
>>elsewhere. So far, only parallel universes seem to hold any promise,
and
>>they certainly do amount to unworldly speculation.� Still, there
seems to
>>be something awfully important about symbolic languages and the
digital
>>communication of information.
> SS: The digital ability is at the basis of all orderly entities --
>living things and machines. Orderliness does appear to me to be the most
>highly evolved general property in the world, as shown by it increase in
>the specification hierarchy:
>{physical dynamics {chemical connectedness {biological form {linguistic
>communication}}}}
> where we see an evolution:
>{physical regularity -> {chemical distinctiveness -> {particular
>representability}}}.
>
>STAN
>
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Received on Mon Nov 6 11:42:14 2006
