>There are a big bunch of chickens and the foxes are eating them. Over
>time there will be some microselection as the gene frequencies are
>modified and those with longer legs are seen to dominate the population.
>
>Now tell me as to "inventive macromutations":
>
>Will the chickens develope teeth as a defensive mechanism?
>
>Will they develop an eye in the back of their head?
>
>How long will it take given the number of chickens, foxes, etc.?
>
>What does the ratio of chickens to foxes have to be at t=0 so that the
>chickens do not go extinct? Or, that there become too few chickens so
>genetically produce an effective mutation rate?
>
>What will happen, and incidently, I will give you as accurate a
>description of the initial conditions of the chickens as you want, why,
>you can even be given the total genetic code of the chicken, mutation
>rate, etc. Just tell me what you want to know and in fact please assume
>that you have all the information you want at time zero.
>
It may in part reflect a Calvinistic viewpoint, but assuming that we knew
exactly what gene did what, what the effect of each mutation would be, the
relative benefits and costs of each change, and what mutations would occur
(e.g., exactly what bases would get hit by a cosmic ray or be miscopied,
etc.), I think it would be possible to predict the evolution. God, being
omniscent and omnipotent, can bring about exactly what He wants through
such a process even though it is practically unpredictable to us.
Speculation on what could happen:
Escape seems to be a more frequent adaptation than sharp teeth for defense,
so better wings or longer legs seem more likely. Sharp teeth might also
interfere with eating grain and bugs. There was a paper several years ago
claiming to have gotten a chicken tooth gene to work; however, it was
questioned whether their protocol was adequate to ensure that the
tooth-making gene really came from the chicken.
Instead of an eye in back, moving eyes from the front towards the side of
the head does occur. This gives closer to 360 degree vision but less
binocular vision. I believe woodcocks have about a 340 degree view without
turning their heads, for example. I would guess that the ability to turn
one's head or turn around does a good enough job, and eyes in the back of
the head would not be greatly favored.
At least one bird has developed poison as a defense. Getting very big is
another possibility. A hyperactive thyroid is the major difference between
a wolf and a dog, a pigeon and a dodo, or a Canada Goose and the giant
extinct flightless goose of Hawaii. It is a bit like Peter Pan, never
growing up in certain respects. Obviously, this is not an advantage
against human predators, as the last two examples show, unless we figure
out that domesticating them will ensure a continual supply. A giant fuzzy
flightless chicken might be a challenge for foxes, though, and requires
only a little mutation.
If you started with colorful chickens, mutation to a more camoflaged
pattern might be favored and relatively easy.
There is the old tall tale of someone who liked drumsticks and developed a
three legged chicken. They ran too fast for him to catch, however. Maybe
that's the next big mutation :)
A problem in communication here is the definition of a major mutation. A
slight change in a gene involved in early development could have a big
effect on the final appearance, whereas extensive mutation of another gene
might have little or no morphological effect. For example, the living
Hawaiian goose, the Nene, does not look all that different from a Canada
Goose, yet it split off earlier than the giant flightless goose. The
flightless goose had a mutation with bigger effects on appearance than did
the Nene, despite having less time.
David C.
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