snails asexual?
Soulstrife
of snails so I don't overpopulate my tank? I saw a really cool BIG snail at
the lfs yesterday. It was cool.
Soulstrife
blac...@dog-play.com
Most snails are hermaphrodic, but that is the opposite of what he is
seeking. "Asexual" means "without sex" or "having no sexual organs." As
snails must reproduce to continue the species the choices are sexual
reproduction or asexual reproduction. Asexual reproduction includes
budding, spore formation, and a variety of others, none of which I have
ever heard applying to snails. I would be surprised to learn that any
snail is asexual (although not shocked - there are many invertebrates that
reproduce asexually). In animals, however, asexualality means that the
animal can reproduce without the presence of another of the same type.
Thus asexuality would not solve the problem.
As noted hermaphrodic organisms are those having both female and male
sexual organs. Despite having both male and female sexual organs few
snails are self fertilizing, generally they do mate - each fertilizing the
otehr. Even though snail do not generally self fertilize if a snail has
ever been housed with another it may well reproduce for a long time after.
What would solve the problem is a snail that is neither asexual nor
hermaphidic, but clearly of only one sex *and* with the inability to
reproduce unless its gametes join with another. (Some females can
reproduce by parthenogensis so simply having a "female" doesn't solve the
problem).
Care should be taken when deciding whether to include large snails in an
aquarium - it is very easy for the snail to die unnoticed and decay with
significant adverse effects on water quality. The very large freshwater
"apple snail" does not reproduce with the vigour of smaller snails.
Environment, available food and other factors will signicantly influence
whether reproduction occurs, and at what rate.
Diane Blackman
di...@dog-play.com http://www.dog-play.com/
- - - - - -
In sci.aquaria Paul Jarvis <pja...@matrix-online.co.uk> wrote:
: Yes I belive thay what's termed Hermaphrodites meaning they have both mail
: and female sexual organs (I think)
:> I heard that some snails were asexual is this true? Can I get certain kinds
Beverly Erlebacher
Soulstrife <soul*nospam*str...@yahoo.com> wrote:
>I heard that some snails were asexual is this true? Can I get certain kinds
>of snails so I don't overpopulate my tank? I saw a really cool BIG snail at
>the lfs yesterday. It was cool.
Many species are hermaphrodites, but some have separate male and female
individuals. The large snails commonly sold are apple snails. They lay
a large egg mass above the waterline, which you can easily remove if you
don't want more snails. Beware that apple snails will readily eat most
aquarium plants.
R. Smith
simple cell division is asexual reproduction. Sexual reproduction requires two
donors of genetic material. In asexual reproduction all genetic material comes
from one individual.
Rock
Free fish pictures on card decks
http://www.wyvern.com/wyvern/html/esdcards/cards10.htm
Soulstrife wrote:
> I heard that some snails were asexual is this true? Can I get certain kinds
> of snails so I don't overpopulate my tank? I saw a really cool BIG snail at
> the lfs yesterday. It was cool.
>
> Soulstrife
R. K. MESSENT
sexual organs within same organism). If the snails were totally asexual,
relying on some process of somatic multiplication, there would be a limit
to their potential for variation since all offspring would be cones in
effect!
Keith Messent, Skipton, UK
Soulstrife <soul*nospam*str...@yahoo.com> wrote in article
<1A1501F2E1040848.8BF7858B...@library-proxy.airnews.ne
t>...
ben_r...@my-dejanews.com
"R. K. MESSENT" <rkme...@daelnet.co.uk> wrote:
> Think you might be mistaking asexual for hermaphrodite (both types of
> sexual organs within same organism). If the snails were totally asexual,
> relying on some process of somatic multiplication, there would be a limit
> to their potential for variation since all offspring would be cones in
> effect!
OK, I'm not sure if we're thinking about the same thing here.
Some organisms have the ability to reproduce both sexually and asexually.
Generally, these organisms will reproduce sexually under sub-optimal
conditions (thereby introducing variation into the population and increasing
survival chances), and will reproduce asexually under good conditions (when
the current organism is thriving, why change its genetic makeup?). It would
make sense if some snails had the ability to do this, and then could have
both male and female sex organs. This explains the terms used, but I do not
know if this is true.
Ben
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David J. James
The chief criterion I dare say is whether they use myopia or mitopia in
their cell reproduction. Only I can't remember which is which and my old
biology exercise books are in the attic and the loft ladder's loose.
Perhaps some scientist (preferably in a white apron like the ones you see
on adverts) can let us know for sure whether snails are myopic.
Regards
D
ben_r...@my-dejanews.com wrote in article
<6pid1d$v7k$1...@nnrp1.dejanews.com>...
Bradford A Pyle
Myopia is nearsightedness. All cellular reproduction is by mitosis.
Meiosis only occurs in the production of gametes. I think your are
confusing cellular reproduction with reproduction/propagation of the
organism.
David J. James wrote in message <01bdb97a$e373aec0$aff6cdc3@ppp>...
Stuart
>I don't think snails can be asexual. Not if the French eat so many of them.
>The chief criterion I dare say is whether they use myopia or mitopia in
>their cell reproduction. Only I can't remember which is which and my old
>biology exercise books are in the attic and the loft ladder's loose.
>Perhaps some scientist (preferably in a white apron like the ones you see
>on adverts) can let us know for sure whether snails are myopic.
>Regards
>D
Errr..... I'm mypoic - it means short-sighted. (In a literal, rather
than philosophical sense of course :) )
Stuart.
--
Stuart Capewell
email: stuart.capewell@REMOVE_ME.vissci.com
Any opinions expressed are not necessarily those of my employers.
David Wetter
> <snip>
> Perhaps some scientist (preferably in a white apron like the ones you see
> on adverts) can let us know for sure whether snails are myopic.
Myopic? Of course they are or the French would never catch them for dinner.
Of course I would hate to do the eye exam. And trying to make the contacts,
oy!
I just love typos, don't you :~)
--
David
"The problem with rules of thumb is that they overlook the fingers."
David J. James
Bradford A Pyle <pyl...@iag.net> wrote in article
<6plb83$ir1$1...@news.iag.net>...
> Do you mean mitosis or meiosis?
>
> Myopia is nearsightedness. All cellular reproduction is by mitosis.
> Meiosis only occurs in the production of gametes. I think your are
> confusing cellular reproduction with reproduction/propagation of the
> organism.
Thank you for this explanation which has put me back on the right track.
But would I not be right in saying that the key to whether snails are
sexual or not is whether they have this meiosis, this gamete producing
going on? Do so-called ''hermaphrodite" organisms use meiosis the same as
you and I/me?
And another question. Why is it, that these apple snails mate and leave
their eggs all strawberry fashion on the tank glass above the high tide
mark, you saw that there were two of them involved in rude behaviour
previously, you've got a glass cover so its nice and humid and the
temperature must be right, and, lo and behold..nothing. No apple snail
young, no pips. Why is this? Every other snail manages to reproduce itself
without hitch, except for the one you want.
Regards
D.
David J. James
Stuart <stuart....@vissci.com> wrote in article
<6plcmj$pa$1...@phys-ma.sol.co.uk>...
>
> Errr..... I'm mypoic - it means short-sighted. (In a literal, rather
> than philosophical sense of course :) )
(snip)
> Any opinions expressed are not necessarily those of my employers.
>
Does that mean that your employers might not agree with your being
short-sighted in a literal sense or that they think you are short-sighted
in a philosophical sense or both?
Anyway, I do sympathise. It's a pain in the neck when one's employer
disagrees with one. And self-employment is no answer, unfortunately.
Regards
D.
David J. James
David Wetter <wette...@lyte.net> wrote in article
> I just love typos, don't you :~)
>
Don't know. Never been to the Greek islands, but I hear they're a very
pleasant place to spend one's time.
Regards
D.
Beverly Erlebacher
>sexual or not is whether they have this meiosis, this gamete producing
>going on? Do so-called ''hermaphrodite" organisms use meiosis the same as
>you and I/me?
Hermaphrodites have both sets of sex organs, and produce both kinds of
gametes, eggs and sperm. Not all are able to self-fertilize - usually
two get together and insemiante each others' eggs. So, yes, they use
meiosis to make gametes the same as you and me.
Some insects and other critters can reproduce by parthenogenesis, i.e
cloning themselves. Often the offspring are haploid. A lot of insects
do this sort of thing, aphids for example multiply like crazy all summer
parthenogenetically, and only produce males and diploid forms for winter
resting stages. Fertilized bee eggs become female (workers and queens)
and unfertilized ones become male (drones).
Btw, not all snails are hermaphrodites. Malaysian trumpet snails (Melanoides
tuberculata) have separate male and female individuals.
>And another question. Why is it, that these apple snails mate and leave
>their eggs all strawberry fashion on the tank glass above the high tide
>mark, you saw that there were two of them involved in rude behaviour
>previously, you've got a glass cover so its nice and humid and the
>temperature must be right, and, lo and behold..nothing. No apple snail
>young, no pips. Why is this? Every other snail manages to reproduce itself
>without hitch, except for the one you want.
Murphy's Law? Apple snails take weeks to hatch, so perhaps you got impatient.
Patrick Timlin's web page has a link to a great apple snail page.
Ian M Smith
> Perhaps some scientist (preferably in a white apron like the ones you see
> on adverts) can let us know for sure whether snails are myopic.
Dunno for sure, but I've never seen one wearing glasses, so probably not.
regards, Ian SMith
David J. James
Thank you very much Beverly. This was great.
Regards
D.