On Thu, 14 Mar 1996 09:21:40 -0500 you wrote:
BH>I found an article by Brian Goodwin on the world wide web that I
>thought would be of interest to the group...
[...]
BH>Neo-Darwinism has failed as an evolutionary theory that can explain
>the origin of species, understood as organisms of distinctive form
>and behaviour. In other words, it is not an adequate theory of
>evolution. ...
[...]
BH>It is clear biology needs a theory of organisms as self-organising
>systems that generate emergent order if evolution is to be
>understood.
I am reading carefully theough Goodwin's book, (Goodwin B., "How The
Leopard Changed Its Spots". I found this interesting little gem that
seemingly invalidates the theory that a self-replicating molecule
like DNA, even if it could arise, could not evolve, but only devolve:
"The DNA of an organism is not self-replicating; it is not an
independent 'replicator'. The only way in which the DNA can be
accurately and completely replicated is within the context of a
dividing cell; that is to say, it is the cell that reproduces. In a
classic experiment, Spiegelman in I967 (Spiegelman, S. 'An in vitro
analysis of a replicating molecule' American Scientist 55 (1967),
221-64) showed what happens to a molecular replicating system in a
test-tube, without any cellular organization around it. The
replicating molecules (the nucleic acid templates) require an energy
source, building-blocks (i.e. nucleotide bases), and an enzyme to
help the polymerization process that is involved in self-copying of
the templates. Then away it goes, making more copies of the specific
nucleotide sequences that define the initial templates. But the
interesting result was that these initial templates did not stay the
same; they were not accurately copied. They got shorter and shorter
until they reached the minimal size compatible with the sequence
retaining self-copying properties. And as they got shorter, the
copying process went faster.
So what happened was natural selection in a test-tube: the shorter
templates that copied themselves faster become more numerous than the
slower, while the larger ones were gradually eliminated. This looks
like Darwinian evolution in a test-tube. But the interesting result
was that this evolution went one way: towards greater simplicity.
Actual evolution tends to go towards greater complexity, species
becoming more elaborate in their structure and behaviour, though the
process can also go in reverse, towards simplicity. But DNA on its
own can go nowhere but towards greater simplicity. In order for
evolution of complexity to occur DNA has to be within a cellular
context; the whole system evolves as a reproducing unit. So the
notion of an autonomous replicator is another spot on the leopard that
turns out to be an incorrect abstraction and it fades out."
(Goodwin B., "How The Leopard Changed Its Spots: The Evolution
of Complexity", Phoenix: London, 1994, p34)
Goodwin seems to be saying that self-replication can only occur if the
whole "cellular context" is already in place? If so, this seems
near-conclusive evidence for Intelligent Design and a near-disproof of
the Darwinian blind watchmaker evolutionary paradigm?
God bless.
Steve
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