<< "...or, perhaps through indirect placement of 
amino acids into such sequences by intermediary
adaptor molecules that brought amino acids to the
nucleotide chain."

I think the 'intermediary adaptor molecules were
polyphosphate chains (pre-ATP). Any nucleotides
or peptides that were in the vicinity of polyphosphate 
chains would have the advantage they gave
(chemical energy) and would be chemically selected.

Those isolated without polyphosphate chains 
would have no chemical energy source.

Thus we would have islands of prebiotic chemistry
where there was polyphosphate chains. The rest
of the prebiotic soup would be mostly inert to change.

***

Follow up:

There is some interesting evidence that seems to 
support the above. 

1. RNA binding to ATP
"Some cellular RNA molecules catalyse reactions that
include bindng to ATP, the common energy
transfer molecule. - Sassanfar and Szostak

2. RNA binding to amino acids
"Zhang and Cech demonstrated that even a 
selected non cellular ribozyme can perform
.... amino acid binding function  (peptide formation)

Therefore I suggest:
All the following 3 things happened at 
about the same time
and in the same  temperature zones 
and that each step helped the other 2 
better survive.

1. RNA strands evolve to tRNA,mRNA, etc.
2. polyphosphate chains evolve to ATP
3. amino acids evolve to protein.

And RNA was connected to ATP was connected
to Amino acids was connected to RNA etc.

Let's go further and say this:

Job one for the above set of 3 was polymerization,
or getting the water out. At first the sun/dry/
heat cycle did that. Then a sun substitute  chemically
evolved (involving polyphosphate chains or ATP) that
allowed chemical energy in water as well as the
original sun energy outside of water. ( In water monomers would be more safe
from UV dimer
damage on pyrimidines)  
and 
Job 2 making variants from these longer polymerized
molecules whether they were nucleic acids, proteins,
polysachharides, lipids,,
and
Job 3  Chemical selection on these variants that
produced ribozymes, denatured and annealed hybrids of all kinds of folded and
or paired nucleotide strands, etc.

Selection pressure would be mostly from the heat cycle.
Then out of two identically thermal stable molecules, that which best  survives
would be chemically selected. 

Tom Hendricks
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