Zachriel
Posts: 2723
Joined: Sep. 2006
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The qualitative results of Gregor's Bookkeeper are fairly straightforward. If the rate of reproduction is low compared to the mutation rate, that is, if many offspring are mutants rather than clones, then deleterious mutations will tend to accumulate in genomes. (They will actually eventually accumulate with any finite population.)
But every once in a while, a significant and favorable mutation will sweep through the population. For a given ratio of favorable to beneficial mutations, the larger the population, the less the fitness will drop before a beneficial mutation has a chance to sweep through the population. So for a given setting, just dial-up the population (or reproductive rate) to avoid genomic meltdown.
Now consider a large population that has been divided into small isolated groups. Many will meltdown. But some, by chance, will experience favorable mutations that will sweep the population. Then if the population is allowed to grow, this subpopulation can avoid genomic meltdown and experience further gains in fitness. Lots of branches, most of which fail, but a few that then prosper. Adaptive radiation.
And we have yet to account for sexual selection, or hybridization.
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You never step on the same tard twice—for it's not the same tard and you're not the same person.
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