Sexual selection is a selection on genetic traits, determined by the preference of an organism that is given the opportunity for mate selection. Some have maintained that the sexually selected characteristics in an organism will be secondary representations of their fitness, such as elongated tail feathers in a bird, or a longer, deeper call in a frog. However, it is generally noted in these examples that the feathers, or the call, are selective disadvantages, and that as a result the organisms that perform the mate selection are conferring disadvantages upon their mates by preference. Consider, for instance, a human population. The female side of the population has (for the purposes of simplicity) a gene called BB, which gives them a big butt. Having a big butt has adaptive significance, for we can say that it makes childbearing easier. Some members of the population have another form bb, which gives them a small butt. Now, let us say that on the male side of the population, there is a gene called the MXLT gene, which causes them to like big butts. Those with the MXLT allele like big butts, and those with the mxlt allele (also known as the Sandler mutation) like small butts. Now, since childbearing is easier on BB females, we would expect that they, and the MXLT males - who breed preferentially with them - would have more children. As a result, the more successful BB and MXLT alleles would grow and eventually become fixed in the population, whereas the deleterious bb and mxlt alleles would dwindle and disappear. However, we are told that this is not the case. Many animals have obvious sexually selected characteristics, and these characteristics are demonstrably disadvantageous in a number of examples. So, how is it that these characteristics became fixed in these populations of organisms?
I heard that mens preference for big breasts actually developed because of their general liking for that butt-like shape (which was actually selected for). Because our species tends to "make love" (for want of a better word) front to front, women have taken advantage of this weakness in men by growing large breasts. Apparently they do not need to be that big to produce milk!
That's a Desmond-Morris-ism, and I hesitate to believe anything that he says about The Human Animal...a lot of his conclusions were pretty circumstantial. In any case, the exemplar film clip that he used in his TV show to show this idea involved two freaky-skinny fashion models, as I recall. He tends to bend evidence, from what I've seen. That same episode postulated that women use lipstick to make their mouth look more like a vagina, which I find a highly questionable idea... EDIT - also the fat content of a woman's breasts decreases as she gets older and as she has more children. A woman with larger breasts will be able to continue childbearing for a longer time...
A survey was taken to see what the ideal woman was, and through the results (the people who were given the survey picked the pictures of the most attractive woman) an average looking woman was selected. Average is simply the most beauty.
That's not necessarily a reasonable conclusion. How was this survey done? Did they average the results? If half the population likes really tall men and half likes really short men, then averaging heights will give you a "most desired" height that no one really likes. This idea of an "average" is sometimes called reification.
It still begs the question. Why do we like women with pouting red lips and big breasts? The latter may be more easily explained I guess.
A question I find just as amazing is: Since men prefer women with big breasts, why does the fashion and entertainment industry keep shoving women at us like Peta Wilson and Lara Flynn Boyle? Women with a shape like a twelve-year-old boy. You'd almost think that the men who are in charge of those industries LIKE twelve-year-old boys. . . . Oh....... I just figured it out. And I mean no disrespect to Peta Wilson. I wouldn't want her to take offense and come after me for revenge. Lara Flynn Boyle, on the other hand, is not only skinny but ugly. Whatever happened to women like Marilyn Monroe and Jane Mansfield, women who actually look like WOMEN? Lucy Lawless was the only female star in years who had a real shape.
Well because shape is not the only "weakness" men have when it comes to selectual selection of women. Another one is that we are attracted to any features which make a woman look young. these features include big eyes, smooth skin and quite importantly, being thin and sometimes 'boyish'. Obviously these traits do not outweigh the cuvaceous traits we seek, in all men. In fact Fraggle, I believe your opinion is held by the majority of men still.
Which animals? Which characteristics -- like, for example, brighter feathers in males of some birds? As far as humans go ... We have eugenics, based on an ideal -- like the Nazi eugenics for example. The reason why boyishly looking women are prefered is probably a response to overpopulation and the fear to reproduce: A curvacious body says the woman could bear a lot of children -- and this is not a desired trait anymore. Anything that reminds of child-bearing is getting more and more bad. (See the fashion in [uh, what's that word: the thing a baby is driven around]: those vehicles look very modern, with massive modern tires and modern colors, they don't look like "reminding of babies" anymore.) Anyhow, the original mating instinct is still there, in its original form: men still like women with curvaceous bodies better for the reasons of reproduction. But reproduction is something that is becoming less and less desirable -- hence preference for thin boyishly looking women. (You can derive the painfuly duality yourself.) *** Another 2 reasons why fasion is showing us thin bodies: 1. Well please, imagine a full feminine body walking there on the catwalk -- with everything shaking. Nah, you wouldn't want to look at that for hours and hours. 2. Fashion is about chasing ideals and images, fashion is about uniformism, not about uniqueness. ('Member: "The summer fashion *dictates* dots/stripes for this year.") No matter what the designers say. They *design*. a) A thin body is far more "repeatable" than a nicely curvaceous body. b) Some degree of some artistic sickness seems to play a part: A nicely curvaceous body looks personal, and it has an immanent personal appeal. This, for some artistic people, may be scary. So they prefer more sterile forms, more impersonal forms. P.S. Take a painting by Rubens -- look at those women. Now put clothes on them ... Yah, they look like total rednecks.
::sigh:: Please Register or Log in to view the hidden image! back on topic people? it's a wonder anything ever gets accomplished in this field with all the men in it. to answer the question about bird feathers we have to look at the reproductive life of a bird. it varies by species so we'll have to pick one. Malachite kingfisher. they are solitary birds but both species build the nest. during the ~15 days eggs are incubating, the female, who is usually solitary, benefits by having a male to provide food and protection resulting in more viable offspring. the males are brightly colored green, blue and orange which takes plenty of his energy and nutrition to produce. the question is, how can using up energy to produce feathers result in more viable offspring? if you look at it from a female kingfisher's perspective who finds it oh so sexy, it tells her that he is well fed and healthy and owns territory in an abundant area. he'd need to in order to be so beautiful. so she's now picked out a mate who can provide for her nest. the more elaborate the plumage, the healthier the male. if the next generation has more males with this lovely feature and more females who prefer it, we have runaway selection.
If men didn't like watching women jiggle, why did they make "DOA Extreme Beach Volleyball"? Perhaps it is for women. SwedishFish: the overall fecundity of the population still decreases, not so?
You're thinking too hard, just like Desmond. Here's a theory: Men like women with full, red lips, because women with thin blue lips are dead.
Ja, but then they do not reproduce so well. Nor does sexual selection work on a dead woman so well either.
to put it in the exemplar case, directional selection on the BB gene increases the mean butt size. as butts become bigger, they become a selective disadvantage for various reasons, one being that they cannot escape from predators as well, but the BB gene remains in the population due to sexual selection. There will be a point where the sexual selective advantages of BB do not outweigh the other selective disadvantages of BB and an equilibrium in butt size will be reached. just a note, after all that, sexual selection is mostly females choosing males (in fact, I cannot think of any where the female is the object of selection), so switch the sexes and the gene to BP (you can guess what BP is).
So there's gonna be no runaway effect for big butts?! Awww damn Please Register or Log in to view the hidden image!
This is true, but that does not mean that it's an incomplete dominant trait - individual butts may never expand beyond a certain size because of the energy cost, without having to appeal to other selective disadvantages. Sexual selection is performed by the male in some species, such as scorpionflies, where (maybe coincidentally and maybe not) the male tends to provide food to the female during mating. In these species the female tends to be "aggressive", and also to develop sexually selected characteristics. I used the BB/MXLT example because I like Sir Mix-A-Lot.
I preferred not to get into the Mendellian genetics of a made-up trait, so I never claimed it was an incomplete dominant trait, AFAIK. Doesn't selection set energy cost limits? I was merely trying to explain runaway selection, where in some fish, and peacocks, the tail becomes bigger and bigger, due solely to sexual selection, until some limit is reached. This limit is selectively determined. Experiments with fish showed this to be true, where tail extensions were added to male fish and females preferred them over non-extended males, but the tails were so long, these fish didn't last long in the wild. Are you sure about this? I think that the females are choosing the males based on the food gift. It's expalined that that's how food gifts evolved. Sexual selection of females on males. Can you provide a reference where female characterisitics are due to male sexual selection? Thanks.
A paper on PubMed that discusses the subject: http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=11569787&dopt=Abstract Another paper on a type of bird where both genders display sexually selected ornamentation: http://www.blackwell-synergy.com/links/doi/10.1046/j.1474-919X.2003.00120.x/abs/
