William Morse wrote:
> Very true. Let's put in some numbers. For an organism having 1000 
> offspring per individual, an s-type has to have a survival rate of .002 
> to keep up with a p-type with a survival rate of only .001, assuming that 
> the p-type can have twice as many offspring. But looked at the other way, 
> if only .998 of the s-type's offspring die in comparison to .999 of the 
> p-type's offspring, the s-type will keep up. This is a sexual advantage 
> of only .999/.998, or slightly more than 1% .Figures don't lie, but liars 
> figure :-)

....but this is getting ahead of the argument. Why do you suppose that 
the two types have different survival rates? Because, I presume,  the 
p-type's are all clones and therefore lack the genetic diversity to 
adapt to enviromental changes, including fast-evolving pathogens, and 
thus survive in smaller numbers.

However, if we assume:

population size is held constant by food supply or geography
there is no reduction in fitness in the initial generations of p-types

the ratio of p to s types climbs rapidly, eg, if the population size N = 
100,000, the s-type would be gone in about G = 36 generations (offspring 
count per female is not an issue, as Anon pointed out). For N = 
1,000,000, G = 42. For N = 10,000,000, G = 49.
(this ignores what might be called the "hopeless male effect", where, as 
the number of s-types females declines, the number of males wasting 
their time mating with p-type increases; this would, of course, only 
serve to increase the rate of s-decline).
So s-salvation depends upon the p-genome becoming maladpative extremely 
rapidly - in less than 50 years, for example, in the case of an animal 
that mates annually.
If the p's survive and drive out the s's, then they may eventually 
succumb as a result of their lack of genetic diversity, and effectively 
drive the population to extinction, but the probability of this event 
will decline over time as mutations accumulate.
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