Date: Thu, 5 Feb 2004 11:38:44 -0800
Subject: OT: evolution of sex myth

[ Later note: My apologies for the lack of capitalization.  I'd sprained or
broken my wrist two days before, and wasn't using the shift key much. ]

darwin pointed out that recently evolved traits will be highly variable, since
evolution is largely a shift in the distribution of variation.  so if you
think human sex behavior is largely determined by biology, but recognize we're
fairly different from the chimps and bonobos (not sure about them) in our
tendency to pair bond, then that means our sex-biology is fairly 'recent' and
may be presumed to be variable.

that does double for our intelligence and language skills, which seem even
more recent.


lots of insects engage in behavior one is tempted to call wooing and courtship
or foreplay.

some of that might be rituals to prove you're both the right species.


my little myth:
in the beginning, life was asexual, and it was good.  then there were
parasites, which could rip through a population of clones.  not good.  somehow
sex arose -- 2 organisms sharing genes before reproducing, so all the genes
could reproduce, but in scrambled packages parasites would have to adapt to.
we could call these hermaphrodites.

then a little herm realized that after sex the other herm was busy raising
half of its genes.  it was supposed to be raising its own offspring, but
that's expensive.  cheaper to throw away the received genes and go mate with
another herm.  and another.

voila, the first male.  soon joined by others.  not parasites per se -- still
contributing something, their genes for parasite resistance -- but cheaters
-- dumping most of the work of sex and repro onto the herms.

ideally the herms might refuse to mate unless you could prove you'd raise a
kid yourself.  but that seems hard to enforce.  instead we get females who
make lemonade out of the situation: if you're going to have all these males
competing over you, at least go and pick the most parasite-free of the bunch.
that being the whole point of the game.  and of course the males do compete.
females do the work, so they have the choice and power.  until males compete
themselves into being bigger than females and rape starts being an option even
for loser males, if the alpha isn't paying attention.

size difference of sperm and eggs comes from the same logic which produces
males in the first place.

also the difference in the sex-determining chromosomes, though i think that's
not correlated with the actual sex.  lots of species don't even have a
sex-determining chromosome, after all, using temperature or other cues
instead.

of course, if the alpha is attentive, most males lose.  so maybe they start
bidding up with help with the offspring.  or natural selection pushes the
species into needing two parents anyway.  at any rate, some species end up
with fathers helping a lot, and we're back near the original herm situation --
two creatures share genes and raise children.  yay.  happy families.  and all
the males get to mate.

except suddenly the females have reasons to cheat -- if she can get the most
parasite-free male to fertilize her eggs, and some other male to help raise
them, she wins.  or her genes do, which is what matters -- they'll be in
extra-strength offspring, not random ones.  sucks for the male though, so we
get even more male jealousy and sperm competition.  

also there's a reason for female jealousy now, don't want the father to spread
his resources.  harem females don't care what the alpha does, since he doesn't
do much for them.  males compete for mates to have sex with, females compete
for mates who'll stick around.

now a few species tilt the other way.  male says "fine, give me this egg i've
supposedly fertilized, and I'LL raise it myself".  so we get seahorses.  or
other fish.  or some birds where the male does all the brooding and nesting
and raising.  like jacanas and phalaropes [the life of birds, attenborough,
"finding partners"]  males are drab, females colorful and they display, if not
actually compete for male nests (book isn't clear about competition).  because
even though the female produces the bigger gamete, the male here is doing more
of the overall work.  

humans seem to be in the pair-bonding/fake hermaphrodite fair sharing space
more than not.  but the inherent instabilities of that space get enhanced by
recency of evolution, bigger size and upperbody strength of males, and enough
cultural flexibility to really confuse things.  any species where males can
voluntarily renounce sex is clearly ones where genes have lost a tight grip on
the reins.  which isn't the same as having no influence.

some villages seem to be more chimp-like, almost -- lots of sex, kids
communally raised.  others have fathers as sperm vectors, with mother's
brother providing the help.  raising niblings [nieces and nephews] isn't as
good as raising children -- 1/4 genes instead of 1/2 -- but at least your
sister knows who her kids are, so it's low risk.  though i've read that
infants look more like their dads than moms, a logical feature to reassure a
dad and keep him feeding you.  but some new alpha males kill other children,
so looking like dad might be just to stay alive, too.

very hard to tell which is the genetic default which decultured humans would
adopt, if there even is a single dominant default, vs. which are cultural
overlays.  

okay, i'm done.  self-reliability rating: i'm not an expert biologist or
anthropologist, though i read a lot, and have been thinking about this stuff
recently because of recent reading.  the above stuff is how i'm making sense
of the world currently, thus "my little myth".  i think it's close to current
leading scientific thinking, but wouldn't bet a lot on it.  and of course
there's tons of more details, but my mild bet is that they'd flesh out this
story, not contradict it.

except for homosexuality, which i don't pretend to explain.  "part of
variation in development, bugs in the system" i'll mutter and run away.

[Note, 16 Oct 2004: A recent paper claimed to have found a modest correlation
between male homosexuality and higher female fertility, in families, and the
with correlation riding the X chromosome.  This was my other simplistic idea
for explaining homosexuality, that genes which caused it would have benefits
which outweighed having gay children.  If true, this correlation might be a
good candidate.  The weakness of the correlation might come from other genes
evolved to counteract the side effect when in males, with gay males being the
males with the female-fertility gene but not the "stay straight" patches.]

some fish change sex in their adult lives.  i wonder if any have non-alpha
males turning female.  going back to my original cheating-herms origin for
males, it'd make sense: if you can't get away with being a cad, buckle down
and raise some offspring like you're supposed to.  i presume that most of the
time the machinery to do that would be costly enough to ensure not being an
alpha male, thus we don't see that strategy a lot.  too bad, it'd be a neat
option: "i don't wanna compete, i just wanna have a kid!"

you can probably see where "nice guys finish last" would come from out of
this, but i should stop typing.

sprained my dominant wrist, that's why few capital letters.

i hate ice
-xx- Damien X-)