Chris:
Yes and no. They are apparently random in the sense of being unplanned, but
not in some other respects; certain genes are better at seeing to it that
their content gets passed on unchanged than others are. This seems to be a
result merely of chemical behavior. In GENERAL, some molecules and some
PARTS of molecules are more sensitive to disturbing forces than others,
therefore, this result is to be expected, even if we did not know that some
genes "actively" repair themselves, or contain redundancy, so that even if a
part is damaged, the appropriate phenotype traits are passed on. Thus, some
mutations DO occur more than others, but I certainly do not know of any
reason to believe that there is some pattern here not predictable on the
basis of chemistry and information-science considerations.
>
Bertvan:
>>And no need for Natural Selection to "design" any new organs, systems
>>or body parts, would there? Natural selection might be just a minor
>>screening process to eliminate failures, those organisms which didn't come
>>out according to plan, mightn't it?
>
Susan:
>actually, that's *exactly* what natural selection is. It's a weeding
>process. Whose plan?
>
Chris
If Bertvan was right here, there should be some evidence of a plan, rather
than merely evidence of fitness. That is, there should be organisms that are
NOT fit, that get killed off a LOT, but that are still mysteriously produced
because of the planner's plan. Instead, we see local matching of organism to
environment, even as the environment changes. If the desert environment that
camels evolved in ("Camelot," of course), were to slowly change to arctic
sea conditions, camels would evolve into creatures suited for arctic sea
conditions (we might end up with the "Camelback Whale," I suppose), or else
they'd die out. What kind of "plan" is it that simply does what Nature would
do if it were totally blind, like Dawkins' watchmaker?
Bertvan:
>>Random mutation and natural selection
>>as an explanation of macro evolution is the part of evolution of which I
am
>>skeptical. While I hear more and more scientists share my skepticism,
>
>It is very obviously *one* of the mechanisms of evolution. I think the
>scientist's skepticism you are hearing about is whether or not it's the
>*only* mechanism. And that skepticism is in the past, since additional
>mechanisms are now known.
Chris:
One such: Sexual recombination. Even if the process of combining male and
female genes were to be perfectly free of mutations, the recombination would
fairly frequently (almost everytime, in a genetically "rich" organism)
produce new genes because genes are not neat, uniform-sized chunks of
genetic code. Many contain sub-genes. If the sub-genes of male and female
with respect to a certain trait get mixed, the result will be a new gene
composed of some sub-genes from one parent and some sub-genes from the other
parent, resulting in a new overall gene, even though no mutation has
occurred.
Also one has been able to define a viable real QUALITATIVE difference
between micro and macro evolution.