Hermaphroditism - why not?
zahi...@yahoo.com
here, and with a question.
Was reading about these snails - I know there are other organisms as
well - that are hermaphrodites.
Now, what are the opinions about selective two-gender sexuality
differentiation, and not hermaphrodites all across the board? Wouldn't
it be geometrically more survivable for the species if individuals
cross-pollinated each other in the mutual, physical sense?
I speculate it might have something to do with scale, since all the
herms I've read of are relatively small creatures. So the relative
investment and complexity involved in having a "female" infrastructure
would increase massively as organisms got larger. Maybe. Maybe larger
creatures with more complex systems are more likely to "mess up"
empirically if they have to do too many things...but I doubt that,
since organisms are so damn complex anyway.
Maybe its a different set of challenges confronted in different
scales/environments, but I can't elaborate since I don't know much
about the topic. Could someone offer their input?
Is it the case the specialization a la classical economics makes
sex-specialised species more survivable in most contexts, and having to
do both roles would just incapacitate inviduals on the whole.
In that case, are there "hive" type organisms (animals) in some
environments that are hermaphrodites, where creatures would just
spontaenously adopt the offspring of other creatures in a sort of
specialised nursery a la honeybees?
I suspect it has something to do with specialization since a lot more
plants (well, that's broad statement I realise, I'll leave it to
someone else to specify) are hermaphrodites even to the extent of
pollinating themselves, _and_ I don't know of plants that really "care"
for their offspring...so creatures that have to invest time later after
birth *would* have to be specialized since the competitive advantage in
doing so is so great depending on context.
I'd appreciate input from you specialists. And could you direct me to
research online regarding this topic.
Thank you.
Tim Tyler
> Hello all, not a biologist, no real biology background. First time
> here, and with a question.
>
> Was reading about these snails - I know there are other organisms as
> well - that are hermaphrodites.
>
> Now, what are the opinions about selective two-gender sexuality
> differentiation, and not hermaphrodites all across the board? Wouldn't
> it be geometrically more survivable for the species if individuals
> cross-pollinated each other in the mutual, physical sense?
>
> I speculate it might have something to do with scale, since all the
> herms I've read of are relatively small creatures. So the relative
> investment and complexity involved in having a "female" infrastructure
> would increase massively as organisms got larger. Maybe. Maybe larger
> creatures with more complex systems are more likely to "mess up"
> empirically if they have to do too many things...but I doubt that,
> since organisms are so damn complex anyway.
>
> Maybe its a different set of challenges confronted in different
> scales/environments, but I can't elaborate since I don't know much
> about the topic. Could someone offer their input?
Two good popular books address this question:
The Red Queen - Matt Ridley, Chapter 4;
Mendel's Demon - Mark Ridley (see "gender" in the index).
Matt concludes that it is down to organelles.
Mark adresses the question of the fate of gender - and says:
``Earthling life is gendered - but this will probably prove to
be a freakish condition in life as a whole in the universe.'' - p.275.
What both authors seem to me to neglect is the possibility that
there may be selective pressure favouring separation of the
genders that stems from the fact that dispersing many small
seeds and acting as an incubator are different strategies
that may require different body plans.
Sexual dimorphism is common - and where it exists, hermaphroditism
may be a sub-optimal strategy - in comparison with having specialised
sexes playing different roles.
I don't know what the future will bring - and while I am pretty sure
that the boundaries between organisms will get a lot more blurred than
they are today, I expect there will remain specialised seed distributors
who *only* distribute information - and manufacturers - who will
tend to be larger, less mobile - and will specialise in actually building
things, without doing much in the way of seed distribution themselves.
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