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February 25th, 2014, 07:57 PM
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Last edited by Stanley514; September 6th, 2017 at 08:55 PM.
But why only 2 sexes.
Just think how much more fun they could have if there were 7 sexes that all had to mate together at the same time to reproduce.
I can't imagine what principal functional differences could exist between those 7 sexes...But why only 2 sexes.
Just think how much more fun they could have if there were 7 sexes that all had to mate together at the same time to reproduce.
You don't have to imagine an alien life form. Seahorses reproduce in this manner. The female is the one producing the eggs, and the male carries them until they hatch.
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Last edited by Stanley514; September 6th, 2017 at 08:55 PM.
Taxonomy is not an exact science. I'd think should we discover alien life, we'd need an entirely new taxonomic structure for each planet/moon. We'd probably need a Europa Linnean structure, or expand the current Linnean structure to include it. I guess we would work out way from bacteria and basic eukaryotes, and progress from there.
As for the OP's example, well as per my point we'd have to adapt how we classify life. Even many extant species don't have a defined male or female, and this largely exists in mammals, birds, reptiles, amphibians, and other advanced multicellular life.
Reproduction in Sea Horses
Sea Horse Reproduction
Conception
In sea horses, the males become pregnant. Their mating involves the female inserting her oviduct into the male's brooding pouch. She does this several times for short intervals to avoid exhaustion. In between the female rests while the male contorts himself to try to get the eggs in place in his brood pouch. After completion the male moves away and attaches himself by his tail to a nearby plant. The female moves away and waits for her oviduct to recede. The oviduct usually recedes within a few hours. The eggs are fertilized and hatch in the male's pouch (Graham 1939). The size of the sea horse brood varies within sea horse species. Some species' broods are as large as 200 (Graham 1939) while others are as small as 8 (Breder 1940).
Okay.. What do sperm and an egg have in common? Everything. However, something like this would never evolve. Simply because why impregnate someone with an immobile egg, while they have mobile sperm to fertilize it. It would be weird.Originally Posted by Stanley514
Determining what is male and what is not, is different in this way, you would not call them mammal, because they are alien, but they do look like mammals if they also breastfeed their young.
* The seahorse female still gets fertilised with sperm. But then transfers the fertilised eggs to the male. This is not the same thing as basically eggs fertilising sperm.
Last edited by Zwolver; February 26th, 2014 at 10:00 AM. Reason: addition to the seahorse
Actually, no. The female seahorse has an ovipositor and she deposits unfertilized eggs in the males brood pouch. The male then fertilizes them and broods them in his pouch.
Seahorse - Wikipedia, the free encyclopedia
It is a bizarre seeming way to do it, but it is what it is.Courtship[edit]
Before breeding, seahorses may court for several days. Scientists believe the courtship behavior synchronizes the animals' movements as well as reproductive state so that the male can receive the eggs when the female is ready to deposit them. During this time they may change color, swim side by side holding tails or grip the same strand of sea grass with their tails and wheel around in unison in what is known as a “pre-dawn dance". They eventually engage in a “true courtship dance" lasting about 8 hours, during which the male pumps water through the egg pouch on his trunk which expands and opens to display its emptiness. When the female’s eggs reach maturity, she and her mate let go of any anchors and snout-to-snout, drift upward out of the seagrass, often spiraling as they rise. The female inserts herovipositor into the male’s brood pouch and deposits dozens to thousands of eggs. As the female releases her eggs, her body slims while his swells. Both animals then sink back into the seagrass and she swims away.
Gestation[edit]
The male releases his sperm directly into seawater where it fertilizes the eggs,[10] which are then embedded in the pouch wall and become surrounded by a spongy tissue.[11] The male supplies the eggs with prolactin, the same hormone responsible for milk production in pregnant mammals. The pouch provides oxygen as well as a controlled environment incubator. The eggs then hatch in the pouch where the salinity of the water is regulated; this prepares the newborns for life in the sea.[12][13] Throughout gestation, which in most species requires two to four weeks, his mate visits him daily for “morning greetings”. They interact for about 6 minutes, reminiscent of courtship. The female then swims away until the next morning, and the male returns to sucking up food through his snout.[12]
Research published in 2007 indicates the male releases sperm into the surrounding sea water during fertilization, and not directly into the pouch as previously thought.[14]
Birth[edit]
The number of young released by the male seahorse averages 100–1000 for most species, but may be as low as 5 for the smaller species, or as high as 2,500. When the fry are ready to be born, the male expels them with muscular contractions. He typically gives birth at night and is ready for the next batch of eggs by morning when his mate returns. Like almost all other fish species, seahorses do not nurture their young after birth. Infants are susceptible to predators or ocean currents which wash them away from feeding grounds or into temperatures too extreme for their delicate bodies. Less than 0.5% of infants survive to adulthood, explaining why litters are so large. These survival rates are actually fairly high compared to other fish, because of their protected gestation, making the process worth the great cost to the father. The eggs of most other fish are abandoned immediately after fertilization.[13]
Questions surrounding reproductive roles[edit]
Reproduction is energetically costly to the male. This brings into question why the sexual role reversal even takes place. In an environment where one partner incurs more energy costs than the other, Bateman's principle suggests that the lesser contributor takes the role of the aggressor. Male seahorses are more aggressive and sometimes “fight” for female attention. According to Amanda Vincent of Project Seahorse, only males tail-wrestle and snap their heads at each other. This discovery prompted further study of energy costs. To estimate the female’s direct contribution, researcher Heather D. Masonjones, associate professor of biology at the University of Tampa, chemically analyzed the energy stored in each egg. To measure the burden on the male, Masonjones measured its oxygen consumption. By the end of incubation, the male consumed almost 33% more oxygen than before mating. The study concluded that the female's energy expenditure while generating eggs is twice that of males during incubation[12] confirming the standard hypothesis.
Why the male seahorse (and other members of Syngnathidae) carries the offspring through gestation is unknown, though some researchers [15] believe it allows for shorter birthing intervals, in turn resulting in more offspring. Given an unlimited number of ready and willing partners, males have the potential to produce 17 percent more offspring than females in a breeding season. Also, females have “time-outs” from the reproductive cycle that are 1.2 times longer than those of males. This seems to be based on mate choice, rather than physiology. When the female’s eggs are ready, she must lay them in a few hours or eject them into the water column. Making eggs is a huge cost to her physically, since they amount to about a third of her body weight. To protect against losing a clutch, the female demands a long courtship. The daily greetings help to cement the bond between the pair.[16]
Another bizarre reproduction tweak is what Surinam toads do.
Sure it is still the female carrying the eggs in her skin, but since you are creating a hypothetical species you could make the male use his skin instead of the female.
Surinam toad - Wikipedia, the free encyclopedia
Examine the gametes of your aliens and designate the smaller (and possibly motile) ones as male. That's normally how it's done on this planet.
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Last edited by Stanley514; September 6th, 2017 at 08:56 PM.
Are you suggesting the people here are not regular?
Don't answer that one.
So what difference does which sex the one carrying the fetus is make to anything then? Harold gave you one example of just such a life form here on earth.
Last edited by dan hunter; February 26th, 2014 at 07:43 PM.
Mammals are not defined by an internal pouch, at all, in biology. It is the presence of a fur and mammary glands that define mammals.
Thus your statement is not correct.
Giving me a "gremlins" feel..
Assuming alien sex works like ours, with the recombination of genetic material and each parent contributing half, what criteria are we using for calling one kind of gamete a sperm, and another kind of gamete an egg? Even in earthly organisms, what makes an egg an egg, is the amount of structural material retained to get things going, where as the sperm contributes little but DNA. And sperm tend to be motile, generally out number and compete for egg access. And of course the presence of x or y chromosome, but that isn't even present in all earthly species. So I can easily see any of these criteria being different in an alien world, and therefore would make the sexes difficult to classify.
In mammals, the incubator also nurses the young, may carry them around, and usually has a tighter care giving relationship, at least right after birth. So any alien life form that did those kinds of things would probably end up being called a "mom" by us.
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Last edited by Stanley514; September 6th, 2017 at 08:56 PM.
An alien version of a female bearing offspring could be a mommalien or a mumalien. [Human terminology equivalents: Mammalian or Mum alien]
What exactly do you mean "scientists believe"? It very much sounds like you disagree with marine biologists on this....
Biologists in general..What exactly do you mean "scientists believe"? It very much sounds like you disagree with marine biologists on this....
Most organisms show sex, in either a X or a Y type chromosome. It is not always this easy however. But in this particular chromosome, both codes will be dominant in most species. This can only be if both chromosomes code for different genes. A male has both, a female has just 1 type.. So we consider an animal a male, if it has both, and female if it has just one type. It's that easy sometimes. Also the case in seahorses.
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Last edited by Stanley514; September 6th, 2017 at 08:56 PM.
Male in biology is defined as having sperm generating organs.
What do you doubt about it specifically?
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