>---Steve--
>
> I dont see how directly manipulating or altering genetic material to
>create animals that are severly handi-capped could support the notion that
>random genetic mutations followed by any natural process could lead to
>anything more usefull than what youve described.
> I dont think that environmental pressures could ever influence the
>propogation of mutations to favor a new envoronment. It's like saying a
>insects mouth will evolve so it can eat on a flower.
But, John, so-called artificial selection shows how novel phenotypes can
survive due to selection pressure. This gets at the "feasibility" question.
The laboratory data show that the selection idea is feasible--environmental
pressure can influence the fixation of mutated genes in the population. If
this didn't happen in the lab, then it would surely put a nail in coffin of
evolution science. In this regard, the attempt to disprove evolution has
failed.
JQ
> I will leave my main point that has be ran over by everyone that has read
>my comments (almost). Natural selection can only act on the expressed
>parts of the genome. So how did anything of complexity evolve? Take the
>human ear, how did it evolve? Somewhere along the line a functioning ear
>had to appear at once from random mutations(without natural selection).
>Unless somehow natural selection has a mind and knows that this mass(you
>and I know it had to start further back than this) of tissue and nerves
>will someday be of use to the body.
The general points regarding natural selection you make here, are
consistent, not inconsistent with the model. You are correct that selection
can only work on the phenotype which is due to gene expression. Selection
then acts after a mutation is made and the phenotype expressed.
Then you go on to say that you don't know how a primordial ear could evolve
"..at once from random mutations (without natural selection)..." The
parenthetical "without natural selection" is where I think you are tripping
over the concept of natural selection. Essentially, the model says that a
primordial ear would arise from random mutations, as you have claimed. This
initial mutation and expression of the phenotype occurs in the absence of
any selective pressure. Then, if this phenotype allows the organism that
has it to reproduce more effectively than an organism without the primordial
ear--this is when selection acts to fix the gene in the population.
In other words, it is not necessary to require the initial appearance of a
primoridial ear to have any connection with selection. The issue of
selection only arises if the new phenotype that results from the mutation is
to be fixed in the genome. Selection, therefore, allows the mutation to be
fixed, and has nothing to do with whether or not the initial or subsequent
mutations occur.
> My main points are these: I dont think random mutations have not been
>shown to do what evolution claims and that natural selection is not a
>viable mechanism, it's reasonings have been distorted to fit the picture of
>evolution.
> I appreciate your comments and your input.
>
Note that up to this point, I have only been speaking on a theoretical
level. It seems that in your last paragraph, you switched the focus of your
criticism. In the preceding paragraphs, and in other posts, you seem to
make the claim that the theory of evolution by mutation and natural
selection is untenable. Then in the last paragraph, you seem to say that
evolution by natural selection has not been proven. Here, I have addressed
the previous criticism, that natural selection is illogical. I disagree
with your assessment of the logic of natural selection--I believe that it
provides a logical model to explain the origins and diversity of species.
As to the second issue, I tend to stay out of the debate of whether or not
evolution is proven or disproven. It seems to me that there is evidence
consistent with evolution, yet there are troubling holes in the data that
one would like to see filled. It remains very possible that these holes
will not be filled to the satisfaction of the model--but this remains to be
shown.
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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