Meadmaker
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- Apr 27, 2004
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May I suggest that with all due respect to the training of your ear, it is oversensitive and far more likely to give false-positives than false-negatives in the "test for creationism"..
May I suggest that with all due respect to the training of your ear, it is oversensitive and far more likely to give false-positives than false-negatives in the "test for creationism"..
May I suggest that with all due respect to the training of your ear, it is oversensitive and far more likely to give false-positives than false-negatives in the "test for creationism"..
I don't think I understand evolution better than Dawkins.
When he talks about "a selection pressure as low as 1:1000" he is using a probabilistic abnalysis, and he there would be no disagreement. When he is making a rhetorical point, counter to Behe's rhetoric, he ignored the nuances.
The nonrandom part is that optimisation occurs, and that poor designs will be weeded out.
Just look at the numbers. If a cod has four-million offspring n average, and the cod populatoin is stable (it is falling) then the average number of reproducing offspring per parent cod is one. Even a thousandfold selective advantage in a single small fry will only improve the chances of survival to reprduction to about 0.025%.
Successfull traits will be still be selected for, but there is nothing remotely inevitable about which will be selected for, as there is such "attrition".
ETA:
Articulett, am I misrepresenting your argument below, and where?
Mutation is "randomish" but those organisms which survive are by definition the best optimised and thus natural selection works because only the best optimised will reproduce
If you don't trust me, ask any biologist you respect or see if you can find any respected biologists that actually words things the way you do. Remember the MSNBC butterfly article-- it was only one mutation... but it brought the population of males back from being 1% of the population to 40% after a year. But that 40% all came from that single mutant.
The proportion of male Blue Moon butterflies dropped to a precarious 1 percent as the parasite targeted males. Then, within the span of a mere 10 generations, the males evolved an immunity that allowed their population share to soar to nearly 40 percent — all in less than a year.
The whole crux of my argument rests on the fact that...
I prefer talking about traits, because if the selection pressures are for smaller individuals (e.g. on an island with a reduced population) individuals with this trait have the advantage, and it it doesn't matter what gene is different, as long as the end result is a smaller organism.
In this case about half the population of offspring would have a smaller mature size than their parents, and thus the selective advantages work for a larger number than ifo one is talking about a single mutation.
In the case of a single advantageous mutation arising initially in one individual; the best (only) way of assessing how likely this mutation is to spread through the population is to perform a probabilistic analysis. It would be more advanced than my simple versions, but it needen't be by much.
Articulett,
In a stable population, a single advantageous mutation provides a 10% selective advantage, and arises in a single (asexually reproducing) organism.
The average brood size for this type of organism is 10.
1) At the birth of this organism, what is the probability of the mutation spreading through the population?
2) The organism makes it through to breed,
a) What is the probability of the mutation spreading now?
b) What is the probaility of the mutation remaining for 5 generations?
3) The mutation is now in 1% of a large popluation, now what is likely to happen?
I think these are usefull types of questions, and ones that can be only answered probabilistically, how would you answer such questions?