Re: john disects your message!:mutations and reproduction

john queen (john.queen.ii@mail.utexas.edu)
Thu, 19 Jun 1997 19:26:11 -0500

---I think this discussion goes to the very heart of evolution. Without
natural selection and random mutations evolution is a sinking ship.
Natural selection is a theory or idea that will only 'float' if the ideas
and theories of random mutaions are feasible. The evidence for natural
selection is the fossil record which is not really evidence for the
mechanistic aspects of natural selection. In addition, the fossil record
reveals patterns that natural selection has a hard time explaining. So
the only real evidence for natural selection is that random mutations can
contribute to the complexity of a genome thus enabling a selection. This
in itsself has only be theorized. The evidence for these types of
mutations is once again the fossil record and the explanation that natural
selection would pick out the most suited genomes.
I think that much more attention needs to be placed on these two concepts.
Often textbooks point to the fossils and the pictures without discussing
the concepts in a manner that is acceptable. Similarities in structures is
not enough evidence(for me) to except the thought that the two structures
came from one another over millions of years.
I appreciate Steves comments because I think he sees where I am coming
from despite my inability to put into concepts into words. I think that
evolution relies on these two concepts and that neither are very clear or
feasible. Thanks for your comments Jim.
john w queen ii

At 12:27 PM 6/19/97 EDT, you wrote:
>Steve Clark writes:
>
><< 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.>>
>
>Wow, I agree with this wholeheartedly!
>
>How can this be?
>
>I think because I now understand your distinction. You say:
>
><<Note that up to this point, I have only been speaking on a theoretical
>level.>>
>
>And I tend to agree with you on this, too. In the realm of pure theory, one
>might make a case for natural selection. But I always jump immediately
back to
>the hard world of data AND common understanding. Thus, you write:
>
><< 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.>>
>
>This is where I have always protested that the theory holds to a hopeful
>"reproduce more effectively" gap filler, even though we have nothing to
>support that. I also stated this, I'm sure you'll recall, as the "imagined
>selective advantage" riff. In THEORY, one can say this always leads natural
>selection to do its magic. But in FACT, it is difficult if not impossible to
>believe, for me at least, that such mutations as a primordial ear or leg or
>lung would ever have the lasting effect on population that is necessary for
>the theory to meet the reality.
>
>Perhaps past differences can be traced to my failure to make the distinction
>you made in your post.
>
>Jim
>