This is not correct. The concept of natural selection does not require that
structures must evolve before they can be selected. In other words, a
primordial ear does not even need to function as an ear in order to give the
host an adaptive advantage. ALL IT NEEDS IS TO PROVIDE ANY ADAPTIVE
ADVANTAGE, WHATEVER THAT MAY BE. I try to amplify this point below.
> I dont think that it's even remotely possible for even the most simple or
>organ or tissue in it's most simple form to be formed from total random.
>I guess the root of my point goes back to this, natural selection would
>have to have something to work with before it can work.
My point is that this is not a problem with the model. I think that you are
getting hung up on the concept here, John.
Let's assume, for the sake of argument, that the paleontologists and
comparative anatomists are correct that wings evolved from forelimbs. The
evidence is that the bone organization of bird wings are very similar to the
bone organization of forelimbs in other species. This would mean that a
wing would have evolved from something that wasn't a wing. Therefore, the
primordial structure of a wing did not need to have a flight function in
order to begin evolving.
Mike Behe too claims that a complex structure like a cilia could not evolve
because removing any one component of the cilial structure renders the
structure unable to function anything like a cilia. However, this
represents an incomplete understanding of evolution. If you remove one
protein from the cilia, it ceases to be able to move. It no longer
functions as a cilia. But, it could very well still be adaptive to the
organism as a means of increasing surface area, for instance. I don't
intend to say that this ishow cilia might have evolved, but the example
illustrates the point that it is very conceivable that simple changes in one
structure can lead to dramatic changes in the function of the organ so that
it is viewed as a completely new structure.
To use another example from Behe. He says that something complex like a
mousetrap could not evolve because the primitive structures would have to
have some mouse trapping capability on which natural selection could work.
But, Behe argues, if you remove any single component of a mousetrap, it
simply will not catch mice--therefore, there is nothing natural selection
can work on. This, in turn, sounds like John Queen's argument. However,
consider how small a change it would require very to turn a catapult into a
mousetrap.
Relating all this to John's question, the major progression from an
appendage to a cilia, or from a catapult to a mousetrap can arise from small
changes in the old "organ" that create entirely new "organs". The question
now is whether the new organ gives the animal a new adaptive advantage. If
it does--THEN and only then would natural selection work to fix the genetic
change responsible for the new organ into the population genome.
This goes back to
>my point regarding random mutations, they have never been shown to form
>anything new that's usefull.
There is abundant circumstantial evidence for this in molecular genetics and
in comparative anatomy. There is also laboratory evidence for this, as I
described in a previous post. What is missing, however, is direct evidence
for this--and such evidence may not be readily forthcoming given the limits
of what science can currently document. The question is whether this fact
is sufficient basis for rejecting the whole theory of evolution by natural
selection. I say no. Those who refer to this limit to evolution science
and then conclude that evolution is not true, usually bring other,
nonscientific considerations to bear, such as a literal interpretation of
Genesis 1.
> One does not need a lab to observe the effects of random mutations. The
>Chernobyl effects are still going on today. Children have been born with
>missing organs, very small or large arms or legs, retardation, cancer, not
>to mention the many herds of live stock and all of their birth defects. I
>really dont think that selectively changing an animals DNA has any bearing
>on natural selection, evolution or random mutations.
To reiterate my point in an earlier post--laboratory data using "artificial"
selection demonstrate that the concept is valid--they do not prove the
concept. In other words, these experiments provided an opportunity to
falsify evolution by mutation and natural selection, and the experiment did
not falsify the model.
Now, it can be argued that the laboratory experiment does not fully
recapitulate what would go on in nature. But this is the nature of
science--most laboratory experiments only approximate what goes on in
nature. Furthermore, it is hard to image how a laboratory experiment to
test evolution by natural selection could be a perfect replica of nature
since we cannot fully measure selection pressure for the simple reason that
environments are constantly changing in unpredictable ways.
Steve
_________________________________________________________
Steven S. Clark, Ph.D . Phone: 608/263-9137
Associate Professor FAX: 608/263-4226
Dept. of Human Oncology and Email: ssclark@facstaff.wisc.edu
UW Comprehensive Cancer Center
CSC K4-432
600 Highland Ave.
Madison, WI 53792
"It is the glory of God to conceal a matter, but the glory of kings to
search out a matter." Proverbs
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