"Elaine Jackson" wrote in
news:nhC9d.29785$a41.4982@pd7tw2no:

This is good stuff. I'd like to ask a couple follow-up questions
if I may:

Is it correct to say that, in any scheme in which there are
exactly two kinds of gametes, one of them makes the journey to the
other, and the latter nourishes the embryo?


Not really, even in humans, the egg has its own journey to make. It
is much shorter than the distance that the sperm needs to go, but
fertilization occurs somewhere in the faloppian tubes, and not on
the surface of the ovary. Many molluscs and other oceanic animals
release the ova and sperm into the water, and neither parent
nourishes the resulting zygote. The fusion of the two cells becomes
the embryo, you could say that one has more stored resources than
the other, but that can go away rapidly when the embryo starts to
hunt and eat.

Are two-gender systems more prevalent? (It seems plausible they
would be most efficient, 2 being the smallest integer bigger than
1.)

This planet seems to only have either one or two genders. There are
some fungi that don't really have morphological distinctions between
the genders, and there are more than two "types", but you really
only need two different "types" to get successful "mating". I have
heard of no organism that requires genetic input from a third or
fourth party in order for reproduction to occur.


If the idea of mating types is overgeneralized in the way you
indicate, what absurdity results?

People might start calling something "male" just because it produces
a microgamete, and "female" because it produces a macrogamete, then
assign roles to the different sexes.


Can you recommend any good references for finding out more about
this kind of thing?

Thanks again for your help.


Sean