David Campbell wrote:
>
> >I
> >> believe there are some ideas on the evolutionary precursors of
> >> photosensitive pigments, but do not remember any detail.
> >************
> >You do not remember any details because you were never given any.
>
> Usually my memory is better than that. I could give you lots of details
> about molecular evolution of the 18S gene in bivalves, as that is what I
> actually study. Evolution of vision pigments is rather tangential. I'll
> see what I can find as I have time, though.
>
> >And I would like to see some evidence to support it.
>
> There was an article a few years ago, I believe in American Scientist but
> possibly Scientific American. New World monkeys normally have only one of
> the red/green color pigments. A simple mutation will change from one to
> the other. If an individual receives one version of the gene from one
> parent and the other from the other, he will have full color visual
> abilities.
>
> >> >From a morphological point of view, any sort of eye from a single
> >> photosensitive cell on up is useful.
> >**************
> >Morphology involves making pencil drawings which ignore the real details.
>
> However, it is the information we have to go on at present. Also, the
> genes have to express themselves in morphology.
>
> >********************
> >How about being accurate.
> >
> >"Complex eyes appear in the follil record at several different times.
> >Those who prefer to see evolution as the mechanism believe that this was
> >due to evolution and those who see a designer prefer to see his action
> >in this."
> >******************
>
> The danger of pronouns! I see a Designer and prefer to see His action in
> this mechanism of evolution as well as the rest of His creation.
>
> >I did not speak of timing as to when. I spoke to the rate of
> >development giving the amount of time available. I am looking for a
> >solid rate of development times time equals organ type arguement.
>
> For a certain amount of time to equal a certain level of development would
> require evolution to always go the same way. This would also require some
> quantified measure of organ development to really speak of a rate. I can
> tell that some eyes are more complex than others, but I am not sure how one
> could calculate what you request.
>
> >Assuming I accept this at face value, now do a calculation with mutation
> >rate, subtract the bad mutations, and give us a number for the potential
> >additional information rate per year.
>
> Mutation rate is not constant, nor is volume of biological information
> well-defined. In a productive year, the amount of information could
> double, but volume of information is not too meaningful. Useful new
> information tends to be kept and bad mutations tend to be lost, so that
> there is an accumulation and not just steady change. All this means that
> the calculation of a precise rate requires more information that is
> available, if not than can be available.
>
> David C.
***********
David
thank you. You have actually exactly answered my question.
Bert M
This archive was generated by hypermail 2b29 : Thu Jan 13 2000 - 18:36:24 EST