Bill writes:

>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 :-)

What you guys are missing in all of your armwaving is that the primary fault
with parthenogenesis lies in its implicit accumulation of defects, generation
to generation. (In fact, it's the problem with all armchair/mathematical
biology. One aspect, often because it is more tractable to mathematical
analysis than others, tends to be emphasized to the exclusion of all other
attributes, and thus leads to some truly odd conclusions that bear little
resemblance to reality.) 

Although Alexy Kondrashov has compiled 27 different advantages attributed to
sexual reproduction in the literature, the big three remain:

     o rapid phyletic adaptation to novel conditions
     o the escape from parasites due to genetic diversity
     o a mechanism that combats the aging of the germline

Which of these is true? All of them are. It's not a "tastes better/more
filling" kind of argument, but without the last advantage, a phyletic lineage
would soon decay into nothingness, in the same way that xerox copy of a xerox
copy soon decays into a page of illegible black and white dots after just a few
dozen replications, and this is the principle reason that apomictic
populations, especially complex organisms, tend to only exist for very short
periods of time.

Wirt Atmar
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