On 13/07/2006, at 3:42 AM, Alberto Vieira Ferreira Monteiro wrote:
Charlie Bell wrote:
Many animal species have a disequilibrium.
Such as?
One way is by polygamy.
In mammals, that just leads to lots of unmated males, with fierce
competition. The overall ratio, if you're talking lions or deer or
something, is 50-50,
The end result is disequilibrium.
....example please? Of a natural diploid population with a highly
skewed male/female ratio. Haplodiploidy causes sex ratio bias, as I
discussed previously.
Homosexuality is either genetic, cultural or a mix of both. In
either case, a lesbian mother in a lesbian society will eventually
have an influence in making the daughter lesbian too.
But those who fail will have more offspring, driving the ratio back
to parity.
Except that those offspring may not be as successful as those
that come from the lesbians, because they weren't as carefully
selected as those.
as those that do, presumably. Unless you're talking about
Even if it does become a common procedure, the selective balance
prevails. Hardy-Weinberg equilibrium models can be used to show how
this happens.
So please enlighten me about this.
I am still waiting for the Hardy-Weinberg equilibrium models!
http://en.wikipedia.org/wiki/Hardy_weinberg
See also Fisher's sex ratio theories, and Evolutionarily Stable
Strategies.
I haven't got the time right now to do a complete work-through of the
problem, for one it was a final-year undergraduate lecture (which
means it's both pretty hard and it's over 10 years ago and I can't
remember the details) and for two, I'm packing the house for a
permanent move to Australia next week... :)
Intuition shows that genetic
manipulation and selection will converge to a mix of Glory Season
and Gattaca.
No it doesn't. Gattaca maybe. Glory Season, only on a new planet with
the geneering done at the time of colonisation.
Why do you think Glory Season so unlikely, with high-tech replacing
the genetic manipulation? Lots of lesbians cloning themselves, and
eventually mixing genes with another lesbian?
Because it would take careful control of a fixed population. If you
reintroduced "wild-type" human genes, they'd out-compete. Maybe in a
highly authoritarian and disciplined commune. But yes, it seems
unlikely. This is science fiction, and it's a lot of fun, but it's
not terribly likely. More likely, IMO, are Baxter's "coalescents",
populations of eusocial humans, but even they'd require some special
conditions to evolve.
Rubbish. Even aphids need males.
Males evolved *because* they were required to cause genetic variation.
Or, more correctly, sex may have evolved to promote genetic
variation. Sexual dimorphism came later. It's not as cut and dried as
you seem to think, it's still one of the great issues in biology.
Wikipedia has a reasonable summary of the status of the problem.
http://en.wikipedia.org/wiki/Evolution_of_sex
If we do *not* want to mutate - are you ready to replace Homo
sapiens for
Homo invictus or some other Evil Race from SF? - then cloning and
elimination
of variety is all we will get.
Mutations are genetic changes at points in the genotype, not
phenotypic changes to population. Assuming you actually mean "evolve"
not "mutate", then, well, it's inevitable. Even the changes you're
talking about are evolution.
Charlie
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