sexual dimorphism in humans

[kora]

So what could possibly be the reason for the comparative physical weakness of human females in relation to human males on average? I think it does occur in other mammals to some extent also. When I say reason I mean from an evolutionary perspective.

theories and stuff. INTP things. GO. And no I am not tired of making gender related posts.

 

[Brontosaurie]

Females are weaker because there has been more evolutionary pressure and selection for strength in males, because males haven't been limited by the reproducive tasks of pregnancy and nurture (resulting in them taking on more survival tasks) and because the reproductive value of their gametes is vastly inferior to the reproductive value of female gametes (resulting in them receiving less external protection).

 

[Seteleechete]

Space for babies(the physical space, fat being more important to conserve rather than waste on muscles ect)?

Jobs for females have traditionally required more flexibility than male counterparts.

If the female could overpower the male they might have more choice about pregnancy/sex.

If the female is in a position of strength they can put their interests before children.

Huh, seeing as the female takes most of the burden of having children giving them more options to refuse really doesn't make much evolutionary sense.

 

[kora]

You would think that pregnancy being something that weakens one in the face of the environment that there would be added survival value in females being at least as strong as males.

 

[Brontosaurie]

You would think that pregnancy being something that weakens one in the face of the environment that there would be added survival value in females being at least as strong as males.

No.

Males don't suffer from the vulnerability of pregnancy, thus have more leverage in strength (strength in males has a higher pay-off, & evolution promotes efficiency), thus are more appropriate for the role of protectors, thus are stronger.

You could also view it this way: Males are not busy with pregnancy and nurture, thus more available for the task of protection. Again, evolution promotes efficiency. Having one sex largely idle would be inefficient.

Remember, both males and females are invested in the offspring. Females carry it, males protect females. It's complementary.

 

[Haim]

Baby takes a lot of energy.
Strong woman don't get raped, meaning they have less potential for children.
What DNA part and materials that makes woman a woman might just have that side effect.
Man focus on hunting protecting etc...
They need the resource for breasts.
They don't need it, they have advantage in manipulativeness it is just more effective.
Man and woman have tendency to not attack/kill woman(woman and children first, man die)

I can make up reasons all day, the bottom line is that it just happened, nature is not an human, nature has no reason, things just happen to be because they can be.

 

[crippli]

Probably the physically weaker males got killed by the females after sex. Only the stronger males survived.

 

[kora]

^ best answer so far. You win thread. Any more takers?

 

[Brontosaurie]

You already got the correct answer from two people...???

 

[Fukyo]

So what could possibly be the reason for the comparative physical weakness of human females in relation to human males on average? I think it does occur in other mammals to some extent also. When I say reason I mean from an evolutionary perspective.

The reason is sex hormones.

There is a trade off between muscles and bone density (strength) and fat (energy).

Testosterone influences muscle development and estrogen fat storage. In females, fat is crucial for reproduction, so much that a woman becomes effectively infertile when her body fat percentage falls under a certain threshold. In order for a woman to attain the same sort of muscle development that men undergo and have the equivalent strength, she would have to be on testosterone, which would of course upset her health and reproductive function. Evidently, the conditions that favor the gestation process won out (since presumably they were effective in ensuring the gestation process was successful, and as such favored by evolution) so women's bodies prioritize energy accumulation instead of muscle development.


Now, I found an interesting article while doing some mild research on this. Apparently estrogen is the oldest of all sex hormones and although organisms did have testosterone, they only evolved the receptors lately (presumably to accommodate the presence of testosterone which appeared as a sort of a by product of estrogen), and the receptors are what counts when to comes to actually expressing the sexual dimorphism. (Note that sexes did exist at the time the testosterone receptors yet did not, which could imply that sex precedes dimorphism, which is interesting)

 

[kora]

You already got the correct answer from two people...???

looks like fukyo is just editing a pretty great post actually. I want as many answers as possible. Then I will think, research, discuss. Your answer was interesting. Good Bronto. *pats the bronto*

 

[Brontosaurie]

looks like fukyo is just editing a pretty great post actually. I want as many answers as possible. Then I will think, research, discuss. Your answer was interesting. Good Bronto. *pats the bronto*

Fukyo's post is essentially a technical elaboration of what i and Haim already gave you. You chose nonsense over that.

 

[kora]

Fukyo's post is essentially a technical elaboration of what i and Haim already gave you.

Technical elaboration is good. I am pleased with this. I'm just gonna let the thread flow, see what happens. Ya dig?

edit: Where is the nonsense apart from in your latest post? (your first two are very good)

 

[Brontosaurie]

Technical elaboration is good. I am pleased with this. I'm just gonna let the thread flow, see what happens. Ya dig?

Yeah sure. But crippli's post wasn't "the best so far", it was nonsense.

 

[kora]

I thought it was funny, which is why I said it was good, obviously I don't believe it to be the true reason. It was my attempt at light hearted foruming.

(r u jealous)

 

[Seteleechete]

Yeah sure. But crippli's post wasn't "the best so far", it was nonsense.

I think it was meant to be taken as " the most humourous so far."

 

[Brontosaurie]

Sorry, i am having trouble with personal boundaries.

 

[kora]

Spoiler

u got jealous

 

[Brontosaurie]

Spoiler

I'm a very jealous person.

That's not the whole thing in this case though. I also took the liberty to extrapolate your motives and defenses - and while i am fully confident in this judgment, it's not relevant.

 

[kora]

You're definitely growing on me.

 

[Fukyo]

Sorry, i am having trouble with personal boundaries.

You are having trouble with something else, and I know what you're thinking. You're thinking higs is looking for replies that validate her worldview or at least ones that are different from what she disagrees with. That might be true, or she just might be interested in other, non conventional theories. You are bothered both by a perceived lack of intellectual integrity and her dismissal of replies you find are sufficient. But why do you have to police what she accepts as true or not though? What stake do you have in it?

 

[Brontosaurie]

You are having trouble with something else, and I know what you're thinking. You're thinking higs is looking for replies that validate her worldview or at least ones that are different from what she disagrees with. That might be true, or she just might be interested in other, non conventional theories. You are bothered both by a perceived lack of intellectual integrity and her dismissal of replies you find are sufficient. But why do you have to police what she accepts as true or not though? What stake do you have in it?

That's exactly the personal boundaries thing i was referring to.

The stakes are multiple and irrelevant. Do you really want to know or should we stay on topic?

 

[kora]

I actually had no theory so far on this except for the rather disturbing "easier to rape" one that has been mentionned, (although I would be willing to accept it even if disturbing.) So I made the thread to get a variety of stuff. I'm not really motivated ideologically, just interested.

 

[Fukyo]

There is an interesting implication that maybe male sexual dimorphism evolved to complement the female, and not vice versa as the Bible would suggest. Whether that was to protect or rape can be anybody's guess. Either choice can facilitate reproduction, and it is likely they were both relevant. There just isn't a definite answer to these questions. This is why I like biology. There are many things we don't know yet about how we came to be.

 

[Rualani]

I thought it was to compete in male hierarchies. Thank god we don't do that anymore.

Spoiler

You thought I was being serious didn't you!

 

[redbaron]

So what could possibly be the reason for the comparative physical weakness of human females in relation to human males on average?

Weakness in what ways? Females have evolutionary advantages over males as well.

Yes, males are stronger, better runners and have higher pain tolerance because they proliferated in an environment requiring them to fight and hunt. They produce more red blood cells than females.

On the other hand females are less susceptible to disease and infection because they produce more white blood cells than males. So they not only get sick less often but they typically recover from sickness faster than men as well. Also skeletal muscle in females is apparently more robust and regenerates more efficiently than males (maybe to do with pregnancy).

The two sexes developed in ways appropriate to their survival in their given environments. They're both hardy, in different ways.

 

[Yellow]

Fukyo and RedBaron are both accurate (except for his suggestion that we're different species).

Haim's is half-cocked, (and frankly, a little concerning). Rape is a "last resort", reproductively, as it significantly reduces the offspring's chances of success. Therefore, it's not likely to be a major factor in the development of our slight (for the animal kingdom) dimorphism.

We have different reproductive roles, and since it is the ultimate goal of every population to remain reproductively healthy, we are physically adapted to such roles. However, since we are an intelligent and "pairing" species, our differences are relatively minor, in order to provide for maximum flexibility/ability to adapt to the demands of our environment.

 

[redbaron]

Fukyo and RedBaron are both accurate (except for his suggestion that we're different species).

LOL, just caught that.

 

[Intolerable]

Eh, not buying most of the answers in this thread.

If you look at other species it isn't out of the ordinary that the female is the larger, stronger of the two.

This was probably true for us as well right up to the hunter / gatherer stage and beyond. Without civilization the only protection the little ones had would be from the mother. Even with humans.

I think the reason why the ideal woman has gotten smaller and more vulnerable while the man has grown more powerful and less vulnerable has to do with our unique evolution. Instead of the mother fending for her young in the case of humans it became the pack / tribe / pride. Coincidentally male lions are bigger than female lions for probably the same reason. Tribal species tend to prefer smaller, softer females for reproduction purposes.

It's an evolutionary advantage when you think about it. A matron in the bear species are forced to both defend and take care of their young. This means they not only have to have enough fat for reproduction but also the energy, muscle, mind and instincts to serve up meals. Filling all these roles spreads them thin so the resources allocate to those areas in a way that doesn't allow for outlier success. Say in the case of an unusually creative matron she may not have enough weight on her to reproduce or may be just a little too slow, a little too weak to provide meals.

These changes in humans are pronounced compared to other species. Large powerful women don't get a chance to breed whereas large powerful men, do. They're seen as integral to the tribal defense. They can die on front line defense and so long as the small soft woman who creates them survives, the species survives.

This means a woman's child rearing abilities become pronounced. Her offspring are extremely healthy and this most likely fueled our intellectual growth as it takes an enormous amount of resources to feed a human brain.

 

[crippli]

^ best answer so far. You win thread. Any more takers?

Cool.

What happens next? Dinner at my place?

The two sexes developed in ways appropriate to their survival in their given environments. They're both hardy, in different ways.

For sure. There are cases where one start to wonder about the actual advantage even where presumed advantages to males are quite firmly established. Like the K2 expedition in 2009. 100% survival rate for females. 54% for males. In quite equal circumstances. As the rule of thumb above 8000m is that you are on your own.

Spoiler

https://www.youtube.com/watch?v=kV6iZRvilwc

 

[redbaron]

If you look at other species it isn't out of the ordinary that the female is the larger, stronger of the two.

Not true for mammals. In majority of mammals sexual dimorphism leans towards bigger males.

Rest of your argument kind of moot in that light.

 

[Haim]

Fukyo and RedBaron are both accurate (except for his suggestion that we're different species).

Haim's is half-cocked, (and frankly, a little concerning). Rape is a "last resort", reproductively, as it significantly reduces the offspring's chances of success. Therefore, it's not likely to be a major factor in the development of our slight (for the animal kingdom) dimorphism.

Every reason I mentioned don't stand in itself but in combination of them.Not only the best individual survive, unless there is significant disadvantage they will survive, an evidence of that is Genghis Khan gene that still live on and humanity stupidity, it is not the "strong" individual that need to survive but the group.

Anyway the reason I really think it happend is that there was notting to stop it, by chance, in other species it happen to went differently, after it happend then came the reasons and fitness for it, not the other way around .

 

[crippli]

Every reason I mentioned don't stand in itself but in combination of them.Not only the best individual survive, unless there is significant disadvantage they will survive, an evidence of that is Genghis Khan gene that still live on and humanity stupidity, it is not the "strong" individual that need to survive but the group.

Anyway the reason I really think it happend is that there was notting to stop it, by chance, in other species it happen to went differently, after it happend then came the reasons and fitness for it, not the other way around .

From what I understand sexual dimorphism isn't something that occurred. It's something that occurs even in contemporary populations. So one doesn't have to look back in time at something that cannot be undone. The mechanism is very much alive. Most studies show that females prefer tall males. Males prefer average height females.

So this could be undone really easily, perhaps already on the next generation if semen from singular height males was used on similar height females. And only on those. Voila. Majority of next generation would not have sexual dimorphism on height.

But when people clearly want dimorphism, then dimorphism is what we get. If one belongs to the majority on this, one already know the answer. Just find out why you want what you want.

 

[Haim]

From what I understand sexual dimorphism isn't something that occurred. It's something that occurs even in contemporary populations. So one doesn't have to look back in time at something that cannot be undone. The mechanism is very much alive. Most studies show that females prefer tall males. Males prefer average height females.

So this could be undone really easily, perhaps already on the next generation if semen from singular height males was used on similar height females. And only on those. Voila. Majority of next generation would not have sexual dimorphism on height.

But when people clearly want dimorphism, then dimorphism is what we get. If one belongs to the majority on this, one already know the answer. Just find out why you want what you want.

The short man won't die, many of them will have children, fat short stupid poor unsocial mans do exist and have children, as long that it only few of the population they can survive, if they consists most of the population they will exstint(actually they will just migrate to other place)