Charlie Bell wrote: > >>> ....example please? Of a natural diploid population with a highly >>> skewed male/female ratio. Haplodiploidy causes sex ratio bias, as I >>> discussed previously. >> >> This ratio can come after a fierce and deadly competition among >> males. Those males that are excluded are, darwinially, dead. > > That a large proportion of the males might not go on to breed > actually says nothing about the sex ration in the next generation. > The ratio continues to be close to 50-50. You are theorising away > merrily, but there are in reality very few examples of skewed bias > in diploids, as I've said. If you'd like to give an example of one > you've found, we can analyse it, but I am telling you now that it's > very rare because of stabilising selection - > Ok, but competition among males creates an opportunity for a polygamous society.
> even in the situation > you're alluding to, it's still an advantage to females to produce > sons as well as daughters - > Not if we accept technological advances. > a skewed sex ratio will make it > advantageous to have more sons, and so equilibrium is restored. It > might be "wasteful" in terms of males, but evolution doesn't care, > it's just success that matters. > That's what must be carefully modelled before we jump to conclusions. Intuitively, it seems that males have no advantage over lesbian females in a society where there are as many males as heterosexual females, and where lesbians can reproduce sexually with other lesbians. However, lesbians _may_ have some advantages over heterosexual females, and this will slightly push the lesbian:hetero ratio in the population towards a lesbian dominance. >>>> I am still waiting for the Hardy-Weinberg equilibrium models! Ok, I saw that, but it's specifically designed for non-sexual genes. > Spoilers for those who haven't read Stephen Baxter's current trilogy, > so I'll link to Ye Olde Wikipedia again... ;) > > First you need to understand eusociality - http://en.wikipedia.org/ > wiki/Eusociality > Ok - I won't read it now. >> I know it's not so simple. Before males appeared as a separate >> subspecies, all creatures were hermaphrodites. > > Or asexual. > Yes, of course. I think you could get what I intended to say :-) >> A sentient species can stop evolution of itself, even if the >> evolution would produce a "better" [to their sentient criteria] >> species > > Only by eliminating all variation (and all sources of variation), or > by only breeding through cloning vats. If there is *any* variation > at all, the *slightest* selective advantage will eventually prevail. > No - taking back to Science Fiction, did you read the "Foundation and Robots" Trilogy? If not, I will not spoil :-) I once saw a sf short movie where kids had to do an intelligence test when they became teens, and the State _eliminated_ those students that were too smart. It seems that most societies are just doing that right now, and trying to eliminate those members that raise above the mud of the population. Isn't this what bullies in schools systematically do? It's a pity that Sentient Species usually use the Sentience to make sure that Sentience does not increase too much :-/ Alberto Monteiro _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
