Naked Science Forum
General Science => General Science => Topic started by: artistic on 12/08/2006 16:12:43
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Can a living thing have more then two genders?
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Depends upon what you mean by gender (there are different definitions of the word), but if you mean that it takes more than two animals to mate, then not on this planet – cannot say about any other planet.
Gender is sometimes regarded as a social rather than a simple physiological things, in which case multiple genders are possible.
George
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Maybe whether there can be more then two types of sexes (male/female)
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Gender is grammatical concept which expresses such contrasts as masculine/feminine/neuter or animate/inanimate. It is also a social expression of the basic physiological differences between men and women. Sex is biological. Gender is social.
It terms of an organisms sex I only can think of the obvious 2. Asexual organism exist. Perhaps this is another or as the name suggests it just lacks a sex. Could a species that requires genetic material from 3 organisms instead of 2 exist in the universe. Would be very interesting I think.
Steven
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Perhaps there might be other types of species on another world with lots of sexes? May never know.
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It is possible, but would need alot of restructuring of DNA (our chromosones are built for being divided in half, t would needa be very different for a 3 part thing
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quote:
Originally posted by realmswalker
It is possible, but would need alot of restructuring of DNA (our chromosones are built for being divided in half, t would needa be very different for a 3 part thing
Animal chromosomes (as far as I am aware, for all animals) come in pairs; but many vegetable chromosomes come in all sorts of combinations (usually in even numbered combinations – the banana is one of the exceptions, but that is why it is almost impossible to sexually reproduce a banana).
Certainly, there is still something even in vegetable chromosomes that requires them to be paired, but in some vegetables you have chromosomes grouped by 6, and at a superficial level these could be divided into 3 as easily as into 2, but they still are only capable of producing 2 sexes.
One problem I can imagine with 3 sexes is the inefficiency involved in having to find 2 mates with which to mate – this could be particularly difficult for those species where one of the partners will die after mating.
Bacteria, with circular DNA that is not paired, ofcourse do not have two separate sexes (are they all considered to be of one sex, or of zero sexes, is open to interpretation).
George
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I think the 2 sexes is enough as the combination of the genetic material of 2 of the organisms of the same species is enough to create genetic diversity.
In a time of universal deceit - telling the truth is a revolutionary act.
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quote:
Originally posted by Mjhavok
I think the 2 sexes is enough as the combination of the genetic material of 2 of the organisms of the same species is enough to create genetic diversity.
Not at all sure that biological sex is there to create diversity. Bacteria have quite enough diversity without sexual reproduction. Rather, it appears to me to be there as a negative feedback to conserve genetic consistency within the species (i.e. to actually reduce diversity by ensuring that mutations that might cause the offspring to diverse from the norm for the species are not allowed to reproduce, or are overwhelmed by genes that do conform to the norm for the species).
What is certainly true is that sexual reproduction is a prerequisite for speciation, and hence bacteria do not have species.
George
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quote:
Originally posted by artistic
Can a living thing have more then two genders?
No! Only one gender is sufficient because it is hard enough for a man to live with a woman without going crazy. One more additional gender then men would jump off of bridges en mass after screaming "I can't live with her anymore ahhhhhhhhh!" [:p]
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Seahorses are great.
It's the bloke who has the babies !
Men are the same as women, just inside out !
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That would be a nice change, although I wouldn't trade the experience for anything as I loved being pregnant and giving birth it was magnificent and awesome I would do it 100 times over if I could. there are no words to descibe how it made me feel and how it felt inside having a lie grow inside of you! Just AWESOME.......................
Karen
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Excellent Karen ....That's exactly what my attitude has been as I have been with my wife through each labour and birth ..and I am sure, with your confirmation that each time , it was a very pleasurable experience...
!..I really can not see what the fuss is about. Us blokes have a far worse time !!
Being called names as the baby is coming out is very hurting you know !
Once, wifey even clawed at my chest and pulled a few hairs out !!..and that hurt !!
However....the sea horse comment was true.
here's some text blatantly copied and pasted here from Wiki.
Reproduction
Seahorses reproduce in an unusual way: the male becomes pregnant. Most seahorse species' pregnancies lasts approximately two to three weeks.
The male seahorse has a brood pouch where he carries eggs deposited by the female. The mating pair entwine their tails and the female aligns a long tube called an ovipositor with the male's pouch. The eggs move through the tube into the male's pouch where he then fertilizes them. The embryos develop in ten days to six weeks, depending on species and water conditions. When the male gives birth he pumps his tail until the baby seahorses emerge.
The male's pouch regulates salinity for the eggs, slowly increasing in the pouch to match the water outside as the eggs mature. Once the offspring hatch, the male releases them and does not care for them. Most will not consume their own offspring, however it isn't unheard of.
Once released, the offspring are independent of their parents. Some spend time among the ocean plankton developing before settling down. At times, the male seahorse may try to consume some of the previously released offspring. Other species (H. zosterae) hitch immediately and begin life in the benthos.
Seahorses are frequently monogamous, though several species (H. zosterae and H. abdominalis among them) are highly gregarious. In monogamous pairs, the male and female will greet one another with courtship displays in the morning, and in the evening to reinforce their pair bond. They spend the rest of the day separate from each other hunting for food.
Men are the same as women, just inside out !
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Originally posted by another_someone
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Originally posted by Mjhavok
I think the 2 sexes is enough as the combination of the genetic material of 2 of the organisms of the same species is enough to create genetic diversity.
Not at all sure that biological sex is there to create diversity. Bacteria have quite enough diversity without sexual reproduction. Rather, it appears to me to be there as a negative feedback to conserve genetic consistency within the species (i.e. to actually reduce diversity by ensuring that mutations that might cause the offspring to diverse from the norm for the species are not allowed to reproduce, or are overwhelmed by genes that do conform to the norm for the species).
What is certainly true is that sexual reproduction is a prerequisite for speciation, and hence bacteria do not have species.
George
In complex multicellular organisms combinations of genetic material between the sexes creates diversity.
Steven
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In a time of universal deceit - telling the truth is a revolutionary act.
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quote:
Originally posted by Mjhavok
In complex multicellular organisms combinations of genetic material between the sexes creates diversity.
But is there not as much diversity in bacteria?
True, you have confined your answer to complex multicellular organisms, but you have not explained why multicellular organisms cannot achieve the same diversity as simple singlecellular by the same means?
Is not the main difference between single and multicellular organisms that the latter actually diversify more slowly than the former, hence my argument that while sexual reproduction might mix and match a limited set of parameters, but at the same time it prevents the organism from diverging outside of those parameters.
George
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George, surely there is much diversity between types of bacteria... but little between generations (if we can even call them that) of the same line of bacteria.
The strength of sexual reproduction is that it produces a range of (subtlely (sp?)) different offspring rather than clones- you get differences due to jumbling of genes as well as simply mutations.
For an organism well adapted to its niche this is no real advantage, since if one is well adapted all will be, but if circumstances change then a species with the ability to vary between generations suddenly benefit since even if the parents can't cope some of the offspring will and can repopulate.
Of course one of the big differences between bacteria and, say, mammals, is going to be that the generation time is much shorter... bacteria, if they're reproducing every couple of hours, will get through a lot of generations (ergo a lot of opportunities for favourable or less favourable mutations in the line) in a given time (say a year or two, or a number of decades) whereas the best mammals can manage is one generation every month or two (many of course much less) so a change in the environment over a period of a few years will leave more species high and dry unless they can shortcut the mutation and use sexual reproduction instead (well, OK, as well...).
Obviously sexual reproduction only works where there is at least one compatible sexual partner available... so there's an element of returning to the norm over time unless there's a strong selection for a particular characteristic... but if there's a strong evolutionary pressure that selects for (say) individuals that have huge (secondary sexual) antlers then the species will drift toward having huge antlers (even if it causes the species to become entirely non-viable and die out... I think there was a species of Irish moose-type-animal that suffered this fate, can't remember the details).