There is a short article from _Science_ (Oct 22, 1999) entitled
"Do Proteins Predate DNA?" that raises all kinds of interesting
thoughts. I thought I'd share one.
The article is written by three evolutionary scientists from
Princeton who argue that rather sophisticated proteins
predate the appearance of DNA. Their argument is
built upon our knowledge of the ribonucleotide reductase
enzymes (RNRs). RNRs are the enzymes which convert
the ribonucleotides (basic building blocks of RNA) into
deoxyribonucleotides (basic building blocks of DNA).
What is interesting about the RNRs is that three classes
exist and all three classes are so different that many
evolutionists argue their origin is polyphyletic. But
the authors argue that the shared mechanism behind this
conversion appears to be beyond the reach of a
ribozyme (an RNA enzyme). They write:
"all RNRs use an unusual and energetically difficult
reaction mechanism based on free-radical chemistry
and the conserved spatial arrangement of two thiol
groups at the active site‰¥ÏIf ribonucleotide reduction
requires such difficult chemistry, is it even conceivable
that DNA arose in a world of ribozyme catalysis?"
To put it simply, it looks like the RNA World would
never have been able to generate the building blocks
needed to make DNA. So, of course, the authors
argue that proteins had to evolve next, with DNA
being the last addition.
But the authors add the following:
"The specific prediction of this argument is that future
research will fail to produce a prebiotically plausible
ribozyme capable of ribonucleotide reduction."
Let that sink in. Here we have three evolutionary scientists
from Princeton making a prediction in the prestigious
journal _Science_. And the prediction is a failure to produce
something. Anyone catch the irony? If not, let me spell it
out.
A common complaint against ID is that it makes no testable
predictions. But ID makes the very type of prediction made
by these evolutionary scientists, namely, if X was designed,
then no plausible X will be produced without intelligent
intervention. We can make the prediction very specific.
For example:
"The specific prediction of ID is that future research will
continue to fail to produce a prebiotically plausible life
form if intelligently guided specification is precluded."
And this prediction has held up for almost 100
years while many have tried to falsify it. Clearly there
is no hand-waving behind this prediction if non-ID theorists
can make analogous predictions to distinguish between
their intra-house models.
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I just came across another recent paper that might be of interest to some.
This one is entitled, "The modern synthesis, Ronald Fisher, and creationism,"
by E.G. Leigh, Jr. (Trends in Ecol and Evol 14;495-498). Leigh is from
the Smithsonian Tropical Research Institute.
In this article, Leigh makes a most relevant admission concerning
the widespread acceptance of the modern evolutionary synthesis:
"The primary problem with the synthesis is that its makers
established natural selection as the director of adaptive
evolution by eliminating competing explanations, not
by providing evidence that natural selection among
'random' mutations could, or did, account for observed
adaptation. Mayr remarked, 'As these non-Darwinian
explanations were refuted during the synthesis‰¥Ï.natural
selection automatically became the universal explanation
of evolutionary change (together with chance factors).'"
Leigh admits that "direct demonstration of the relationships
between available variation, natural selection and evolution
was neglected." In fact, the abstract of the article states:
"The central problem with the synthesis is its failure
to show (or to provide distinct signs) that natural selection
of random mutations could account for observed levels
of adaptation."
Before I continue, I should make it clear that Leigh
in no way seems skeptical of the modern synthesis.
He clearly thinks these "neglected demonstrations"
will be forthcoming and then draws from the work
of Ronald Fisher to offer suggestions. But what is
interesting is that this evolutionary scientist from
the Smithsonian seems to be saying similar things
as many anti-darwinists in admitting the lack
of evidence that natural selection has been behind
the adaptations we see (aren't we told this has
been settled decades ago?).
But there's much more. First, Leigh admits that
the neo-Darwinian synthesis has become so widely
accepted only because other non-Darwinian
mechanisms have been refuted. But it should be
obvious that the "competing explanation" of
ID was never eliminated; it was simply ignored
and flippantly dismissed to begin with. The implications
of such exclusion are enormous - the reasons for
thinking evolution occurred via natural selection
are simply a consequence of excluding ID and comparing
natural selection with what remains. Put simply, science
has found absolutely nothing to indicate something
from the ancient past arose via natural selection *rather*
than intelligent design. Nothing.
To his credit, Leigh seems to understand this. He writes,
"However, the failure to provide clinching evidence
gives antidarwinians no reason to substitute natural
selection for God in their view of the world. Neither
have antidarwinians any vested interest in a mechanistic
explanation of the origin and evolution of life; if we
want them to accept one, it will have to be convincing."
Unlike a Dawkins or Gould, it is true that antidarwinians
have no vested interest in coming up with a mechanistic
explanation. Thus, the evidence they view as substantial
can look like grasping-for-straws when you remove
their vested interest.
Leigh's solution is to find traces that natural selection was
involved in the origin of major historical adaptations (it's about time
some darwinist finally (after 100 years) got around to the only
data that matter).
He writes:
"Identifying fingerprints of the crucial role of natural
selection in macroevolution would reveal the decisive
role of selection in evolution."
Now, if we can look for fingerprints of natural selection, I see
no reason for excluding from sight the ability to detect
fingerprints of intelligent selection. But alas, Leigh's
attempt to detect fingerprints of natural selection fail
miserably at distinguishing it from intelligent design.
Thus, he correctly identifies the problem, but then
proceeds to do more of the same thing (looking for
evidence of natural selection by a priori exclusion
of intelligent design).
The two fingerprints he suggests are as follows:
1. According to Fisher's views about the role of natural
selection, "for groups to become cohesive units, an
individual's advantage must become identical to the
good of the group, or an enforceable community interest
must evolve among a group's member." Leigh argues
that evolution is characterized by transitions whereby
"cooperating entities were transformed into cohesive
higher-level units of selection," including the, "aggregation
of genes into genomes; the transformation of bacteria,
containing various commensal or symbiotic microbes within
their cells, into genuine eukaryotic organisms; the transformation
of multicellular aggregates into true metazoan individuals;
and the transformation of insect groups into cohesive
societies with complex divisions of labor."
Now, I don't know enough about the last two to make informed
observations, but I do know a few things about the first two.
And I seriously question whether either happened. I see no
evidence that life forms once existed as a mere bunch of
genes that aggregated into a genome. Thus, to detect
a fingerprint of natural selection here, Leigh makes a necessary
assumption that is not needed by ID. Thus, this fingerprint
may simply be an artifact that follows from a priori exclusion
of ID. As for the origin of eukaryotes, the success of the
endosymbiont theory in explaining mitochondria and
chloroplasts is often invalidly extrapolated to mean
endoymbiosis is at the core of the origin of eukaryotes.
But eukaryotes are not bacteria with mitochondria, nor are
they a conglomerate of bacteria. There are many features
of eukaryotes not found in bacteria (cytoskeleton, nuclear
pore complexes, spliceosomes, sterols in the membranes,
etc.). Once again, Leigh is assuming an event to detect
his fingerprints, an assumption not required from an ID perspective.
[Besides, if we adopt this criterion, should we admit their is
no fingerprint of natural selection behind the origin of birds?]
If Leigh wants a fingerprint that will convince the
antidarwinians, he will need something far better than
this (which are, after all, only data patterns consistent
with natural selection - but then just about anything
can be made to be consistent with natural selection).
To find a suggestive fingerprint, he'll need data which
is expected from natural selection, but not expected
from ID. To find a convincing fingerprint, he'll need data
expected from natural selection, yet predicted not to
exist by ID. Raising hypothetical examples of cooperating
individuals into a group that is selected as a unit satisfied
neither.
What Leigh is reaching for instead is a "fingerprint of
the role of natural selection in macroevolution."
An ID proponent has no reason to exclude a *role*
for natural selection in the history of life. But a role
is not a cause. An actor may play an important role,
such that his absence will bring a halt to the play, but
the actor's role need not be the cause of the play. Likewise,
an intelligent agent that sought to design an entity and
deposit it on the biosphere would more than likely recruit
natural selection to play the *role* in retaining that
entity among the biosphere.
2. Leigh's second fingerprint is modularity. He proposes
that natural selection implies life should be modular, where
"the restriction of a gene's action to a particular environment
or 'compartment' or facet of the phenotype" is characteristic.
He writes:
"The virtue of modularity is that it allows selection on
one feature without compromising adaptations in others."
Of course, it is true that modularity appears to exist in life.
But the question is exactly how much modularity is
predicted by natural selection? For life is far from being
perfectly modular. Mutations are often pleiotropic as
systems are often intimately integrated.
But the main point is that Leigh's fingerprint again
does not distinguish between natural selection and
intelligent selection. Modularity is a feature that is
every bit as expected from intelligent design. In fact,
common experience with intelligent design easily
illustrates this as my pick-up truck is clearly a conglomerate
of modular systems working together. Designing a
life form around modular subsystems is about imparting
flexibility into your creation, something that makes
darn good design sense. In fact, without realizing it, Leigh
begins his concluding discussion of modularity with
a sentence that I suspect many ID proponents could
accept in its most literal sense:
"The design of organisms to facilitate the evolution of
their populations provides another reason for believing
that natural selection plays a crucial role in evolution."
In the end, I am pleased to see that Leigh agrees with
me that no substantive evidence or demonstration
has ever been shown that natural selection was the causal
factor behind any of the major changes in life's history.
I am likewise pleased to see he recognizes it is his
burden to come up with convincing evidence for
such claims (while acknowledging the antidarwinians).
But his solutions will fail to convince his target audience
(the antidarwinians) simply because he continues in
the tradition of ignoring and flippantly dismissing ID
by looking for things that will convince that already
convinced. Perhaps one day the darwinians will seriously
listen and contemplate the views of the antidarwinians
without recasting those views in the light of straw men.
But as long as they continue to talk amongst themselves,
I doubt they will ever come up with anything more convincing
than has already been proposed.
Mike