[asa] RE: [asa] Rejoinder 7D from Timaeus – to Iain Strachan

From: Hofmann, Jim <jhofmann@Exchange.FULLERTON.EDU>
Date: Thu Oct 23 2008 - 16:49:57 EDT

Interesting that lizards were chosen as an example, since there is a study on lizard natural selection
Jim Hofmann


Rapid large-scale evolutionary divergence in morphology and performance associated with exploitation of a different dietary resource
1. Anthony Herrel<http://www.pnas.org/search?author1=Anthony+Herrel&sortspec=date&submit=Submit>*<http://www.pnas.org/content/105/12/4792.full>,†<http://www.pnas.org/content/105/12/4792.full>,‑<http://www.pnas.org/content/105/12/4792.full>,
2. Katleen Huyghe<http://www.pnas.org/search?author1=Katleen+Huyghe&sortspec=date&submit=Submit>†<http://www.pnas.org/content/105/12/4792.full>,
3. Bieke Vanhooydonck<http://www.pnas.org/search?author1=Bieke+Vanhooydonck&sortspec=date&submit=Submit>†<http://www.pnas.org/content/105/12/4792.full>,
4. Thierry Backeljau<http://www.pnas.org/search?author1=Thierry+Backeljau&sortspec=date&submit=Submit>†<http://www.pnas.org/content/105/12/4792.full>,Β§<http://www.pnas.org/content/105/12/4792.full>,
5. Karin Breugelmans<http://www.pnas.org/search?author1=Karin+Breugelmans&sortspec=date&submit=Submit>Β§<http://www.pnas.org/content/105/12/4792.full>,
6. Irena Grbac<http://www.pnas.org/search?author1=Irena+Grbac&sortspec=date&submit=Submit>ΒΆ<http://www.pnas.org/content/105/12/4792.full>,
7. Raoul Van Damme<http://www.pnas.org/search?author1=Raoul+Van+Damme&sortspec=date&submit=Submit>†<http://www.pnas.org/content/105/12/4792.full>, and
8. Duncan J. Irschick<http://www.pnas.org/search?author1=Duncan+J.+Irschick&sortspec=date&submit=Submit>β€–<http://www.pnas.org/content/105/12/4792.full>

Edited by Gordon H. Orians, University of Washington, Seattle, WA, and approved January 31, 2008 (received for review December 19, 2007)


Although rapid adaptive changes in morphology on ecological time scales are now well documented in natural populations, the effects of such changes on whole-organism performance capacity and the consequences on ecological dynamics at the population level are often unclear. Here we show how lizards have rapidly evolved differences in head morphology, bite strength, and digestive tract structure after experimental introduction into a novel environment. Despite the short time scale (β‰ˆ36 years) since this introduction, these changes in morphology and performance parallel those typically documented among species and even families of lizards in both the type and extent of their specialization. Moreover, these changes have occurred side-by-side with dramatic changes in population density and social structure, providing a compelling example of how the invasion of a novel habitat can evolutionarily drive multiple aspects of the phenotype.

-----Original Message-----
From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On Behalf Of David Campbell
Sent: Thursday, October 23, 2008 1:14 PM
Subject: Re: [asa] Rejoinder 7D from Timaeus – to Iain Strachan

""It would be interesting to ask the world's 100 leading Darwinists to
predict what
will happen to a population of lizards released into a new territory,
100, 200, and 500 years from now, and keep a record for posterity, and
see how well the Darwinists would do without the advantage of
hindsight. "

Actually, it depends on the territory. I can easily predict what will
happen if the territory is in the middle of the ocean or Antarctica,
based on evolutionary premises.

Depending on the choice of lizards and the choice of territory, some
fairly specific predictions may be possible. For example, throughout
the Caribbean there are anole lizards (also present in SE US).
Islands or island groups have different species that are specialized
more (based on body proportions) for living in trees or for living on
the ground. Genetic analyses indicate that, in most cases, different
species on the same island/island group are more closely related to
each other than ground or tree forms from separated islands. In other
words, evolution from one lifestyle to another has happened a lot.
So, we can reasonably expect that, if a tree-type anole population
gets experimentally introduced to an isolated, treeless (but with
suitable lizard habitat), lizardless island, they will very probably
evolve proportions more like the ground-dwelling species. In fact, it
takes a lot less than 100 years for this trend to be detectable, as
the experiment has been done.

Depending on the island and the type of predators (if any) present,
certain colors might be favored over others, though this is
complicated by the ability of some anoles to change color. Less
readily predicted is the potential effects of sexual selection. In
anoles, generally the male displays (to scare rivals and attract
females) by doing push-ups and displaying a colorful flap of skin
under his neck. Different species have different colors. Some shift
in the exact color pattern is very likely, simply because the
experimental population will almost certainly not be completely
representative of the average of the source population in male
features and female preference and because mutations happen. However,
predicting exactly what change will happen is very difficult because
there's no one solution-it might get darker or lighter or change

I don't know if we know enough about gene function and development in
anoles to determine exactly what options a lizard has for changing its
proportions, color, etc. Probably there are multiple genes involved
and different ways that could cause a similar morphological end
result. Predictions relating to that would be probabilistic (e.g.,
"in known cases of evolving from tree-morph to ground-morph, Gene A
mutated x% of the time, Gene B had mutation 1 y% of the time and
mutation 2 z% of the time, etc.).

Evolution is statistical rather than deterministic, so all this is a
function of probability. There are also plenty of complicating
factors, e.g., if the island takes a direct hit form a major
hurricane, the population may be wiped out and cease to show any
evolutionary change.

If we had a complete genetic characterization of the starting
population, we might have a few other predictions, though they would
be statistical, relating to the probability of mutations.

The fact that evolution is best determined in hindsight is an aspect
of its non-teleological nature within the confines of science. This
does not prove that God cannot have direction achieved by this means;
rather, it shows that evolution itself is not progress and has no
inherent goal. This accords well with Genesis 1-it is not some
supernatural entity with goals of its own, it's just a pattern of
God's running of creation.

Let's take another example. Ask a bunch of leading physicists to
predict the exact configuration of a set of six objects interacting
through gravitation over the long term. They will tell you that a
system with more than two objects is not fully predictable. Therefore
gravity is bunk and I can jump out the window safely? Especially
since it is ateleological and therefore promotes atheism? No,
therefore the proposed system is too complex for prediction of a
single outcome with total certainty. Gravity and any other science
can't tell us about progress or "ought to" or anything of the sort
because science is incompetent to deal with such topics. A two-body
problem in gravity can be worked out in detail, but so can the simple
evolutionary questions such as "Given a precise set of environmental
conditions in lab, which flour beetle species will win out?" or "What
will happen if we put together you, a hungry bear, and an antelope if
there is enough room to run away but no weapons or other accessory
defense available? What if there's little room to run but
intellect-dependent opportunities for escape?"

SImilarly, is it reasonable to demand from evolution a full account of
exactly what mutations happened to produce, e.g., the full series from
an eyeless organism to one with well-developed complex eyes?
(Although if my eyes are directly attributed to ID-style action I
might check the warranty regarding things only being in focus if they
are within about 10 cm. On the other hand, I don't need a hand lens
as much as most people.) It depends on what the question is. As a
rebuttal to the claim that science absolutely disproves all
possibility of any intervention-style action within the formation of
organisms, it is valid. Even if we had full data on the molecular
workings of every living animal and step by step models of how every
aspect had evolved, mutation by mutation, that would not disprove
either the possibility that a) some extinct organism had an
inexplicable feature or that b) the intervention was too subtle to
notice. Even a time machine, allowing unlimited data on past
organisms (including the budget for all the molecular biology lab work
and analytical time), could not disprove the claim that more subtle
interventions were happening, though that claim would sound very much
like special pleading to excuse a god of the gaps. In other words,
science cannot rule out intervention-style implementation of design,
though it can say that it is not necessary in a given case.

However, it is unreasonable to expect evolutionary biology to have a
full mutation by mutation explanation of the origin of, e.g., the eye
at present or in the near future because we simply do not have the
necessary data and technology at this time (As the eye has arisen
several times, a specific eye must be selected, though fairly similar
patterns of evolution probably took place in most cases.). In a few
cases, we do have a well worked out mutation by mutation history of a
particular gene. But to have a full mutation by mutation model for
the eye would require knowing what every gene is that is involved in
making and operating the eye, examining the genes in related species
with successively simpler eyes, comparing the genes to identify
similarities to other genes, knowing the full function of each of the
genes, developing computer models of evolution to recreate changes
back through time, developing models (computer/in vitro/in vivo) to
confirm the functionality of the posited intermediates, and putting
all the data together, not to mention finding funding and time. Even
then, we would have a coherent model, but not proof that it was
exactly that set of mutations instead of a slightly different set-one
would need a data set like Lemski's except with samples taken at
regular intervals over geologic time to trace the exact pathway that
was followed. Thus, saying "I don't believe in evolution because it
hasn't explained something that's beyond our current technology to
develop the sort of explanation I want" is not a very reasonable
position. We're still in the early stages of learning what molecular
features are present in organisms. DNA sequencing of anything has
been possible for 30 years; large-scale sequencing only for a little
over a decade. Similarly, accurate prediction of protein
configuration and function from the amino acid sequence is beginning
and not yet complete. Working out what all the pieces do is in its
early stages.

Additionally. most work in biochemistry is not evolutionary. Mostly,
it's either just trying to figure out how things work or trying to
find things of medical, biotechnological, agricultural, or other use.
Evolutionary biology is not a high priority for funding nor hiring.

Is ID a god of the gaps? Often but not always. Ask any ID advocate
directly, and the god of the gaps is rejected. ID gets defined as
being about the positive effort to identify "design". However, ID
advocates also routinely make gap-type claims, such as Johnson's
insistence on fingerprints all over or Dembski's claim that ID is
essential to religion or the standard disparaging of methodological
naturalism as leading to atheism. All of that is endorsement of a god
of the gaps and thus of atheistic denial of God's providence.
Likewise, ID also gets defined (especially in marketing to the average
person in the pew) as the Christian alternative to evolution, and no
matter how often ID advocates say it's not really about attacking
evolution, they always seem to go on and attack it. This is a gap

Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"

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Received on Thu Oct 23 16:50:48 2008

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