Why does natural selection favor convoluted vaginas?

In summary, Duck vaginas are a good example of sexual selection. Females of many species use sexual selection to choose the best mate for their offspring. This is because males of these species have an operationally unlimited supply of sperm. Females of the human species use different methods to enforce their selective preferences.
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While it's true that it prevents successful penetration by unwanted males, but any unsuccessful fertilization by any males, unwanted or otherwise, results in fewer offsprings. This means lower genetic fitness for convoluted vaginas.

EDIT: Not in humans. But in other species in nature such as ducks.
 
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Natural selection is not about having the most offspring.
 
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@Orodruin has it. Positively stated - it is about survival of offspring, so they live long enough to provide genetic material for the next generation. And FWIW there is no such thing as a convoluted vagina in humans. You could have mentioned that this is about ducks.

So, let's keep this discussion within bounds of what is, rather than what could be imagined.
 
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jim mcnamara said:
And FWIW there is no such thing as a convoluted vagina in humans.

Not in humans. But in other species in nature such as ducks.
 
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Yes, see my edit above. This is in part of what is called sexual selection. Most examples you will see are in birds anatomy, colors, calls, etc.

Note that some aspects of sexual selection improve the odds of successful mating and offspring but can be detrimental - like brightly colored male birds are easier for predators to see. Females are often mottled brownish gray colors so they blend in while incubating eggs - sometimes called brooding.

http://evolution.berkeley.edu/evolibrary/article/evo_28
 
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Some animals have limits to how many eggs the females have. (I am guessing ducks are no different.)
Females of many species also put a significant amount of their time and energy into raising the offspring.
Males on the other hand have an operationally unlimited supply of sperm.

This is the evolutionary basis for females of these species to be selective with whom that mate.
They will want the best genetic contribution for their offspring obtainable, thus sexual selection on the part of the female.

Females of the human species use different methods to enforce their selective preferences.
 
  • #7
Happiness said:
Not in humans. But in other species in nature such as ducks.

Not just ducks: pigs, whales and dolphins as well.

This matters to the discussion because it shows there is a general principle involved, not specific to ducks (or birds), and that there are many 'solutions' in the sense that there are different solutions for vision: at least 10 different types of eyes exist.
 
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My 7th grade biology teacher explained, of breeding sweet pea flowers, that nature takes the <whole number> of <viable, healthy> plants, throws out the ones that are too (big, small, color deviant, vulnerable to pests, etc.) near the edge of viability or sustainability, so we are left with the best result for the current climate and conditions.

It seems to me that a convoluted genetic pool would not promote a genetic weakness, but prevent a genetic pollution of sorts. But, I should also think that breeding habits would play a part in this particular question, as the convolution may serve to balance or correct an aspect in process which favored diversity among smaller populations, previously.

"We must not presume a finished process, but look to where it may be going. What does the current evidence suggest a future generation might be? What information does our climate and environment provide for the genetic equation? Does nature build in resistance to pollution?" ~ A Great Teacher with a difficult name, who got us all to look at the whole system.
 
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Related to Why does natural selection favor convoluted vaginas?

1. Why do some species have convoluted vaginas?

The shape and structure of a species' reproductive organ is determined by natural selection, which favors traits that increase the chances of successful reproduction. In some species, a convoluted vagina provides a physical barrier that prevents unwanted sperm from entering and fertilizing the eggs of multiple males.

2. How does a convoluted vagina increase reproductive success?

A convoluted vagina can increase reproductive success in a few ways. Firstly, it can prevent unwanted sperm from entering and fertilizing the eggs, ensuring that only the sperm from a chosen mate will have a chance of producing offspring. Secondly, it can also create a longer and more difficult path for sperm to travel, increasing the chances of only the strongest and most fit sperm reaching the eggs.

3. Do all species have convoluted vaginas?

No, not all species have convoluted vaginas. This trait is more common in species where multiple males may attempt to fertilize a female's eggs, such as in promiscuous species. Other species may have simpler reproductive organs that are better suited to their specific mating strategies.

4. Can the shape of a vagina change over time through natural selection?

Yes, the shape of a vagina can change over time through natural selection. As the environment and mating strategies of a species change, certain traits may become more or less advantageous. This can lead to the evolution of reproductive organs, including the shape of the vagina, to better suit the needs of the species.

5. Are there any drawbacks to having a convoluted vagina?

While a convoluted vagina can increase reproductive success, it can also have some drawbacks. In species where multiple males may attempt to mate with a female, a convoluted vagina may make it more difficult for the female to choose a specific male's sperm. Additionally, the physical barriers created by a convoluted vagina may also make it more difficult for the female to expel waste and give birth, potentially leading to health issues.

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