thinker_jeff Posted February 16, 2011 Posted February 16, 2011 LINK: http://www.pnas.org/content/early/2011/02/04/1011876108 Abstract Sexual selection in natural populations acts on highly heritable traits and tends to be relatively strong, implicating sexual selection as a causal agent in many phenotypic radiations. Sexual selection appears to be ineffectual in promoting phenotypic divergence among contemporary natural populations, however, and there is little evidence from artificial selection experiments that sexual fitness can evolve. Here, we demonstrate that a multivariate male trait preferred by Drosophila serrata females can respond to selection and results in the maintenance of male mating success. The response to selection was associated with a gene of major effect increasing in frequency from 12 to 35% in seven generations. No further response to selection, or increase in frequency of the major gene, was observed between generations 7 and 11, indicating an evolutionary limit had been reached. Genetic analyses excluded both depletion of genetic variation and overdominance as causes of the evolutionary limit. Relaxing artificial selection resulted in the loss of 52% of the selection response after a further five generations, demonstrating that the response under artificial sexual selection was opposed by antagonistic natural selection. We conclude that male D. serrata sexually selected traits, and attractiveness to D. serrata females conferred by these traits, were held at an evolutionary limit by the lack of genetic variation that would allow an increase in sexual fitness while simultaneously maintaining nonsexual fitness. Our results suggest that sexual selection is unlikely to cause divergence among natural populations without a concomitant change in natural selection, a conclusion consistent with observational evidence from natural populations.
Mrs Zeta Posted February 16, 2011 Posted February 16, 2011 There is a world of difference between flies and men. It would be interesting to see any human studies. Also, I would love to see studies correlating male or female attractivenes and intelligence (animal or human results will do).
Mr Skeptic Posted February 16, 2011 Posted February 16, 2011 There is a world of difference between flies and men. It would be interesting to see any human studies. Or studies in peacocks. 1
Moontanman Posted February 16, 2011 Posted February 16, 2011 Good example skeptic, there were so many examples that disprove this i didn't know where to start, hard to think of an animal that does not use male attractiveness to attract females.... almost any animal with good eye sight?
Mrs Zeta Posted February 16, 2011 Posted February 16, 2011 (edited) Or studies in peacocks. No, not in animals but in humans. I know a lot of ugly men who don't try to improve their appearance. They still manage to get married and have (ugly) children. In the case of humans, I think there is a tradeoff between appearance and intelligence. Edited February 16, 2011 by Mrs Zeta 1
thinker_jeff Posted February 16, 2011 Author Posted February 16, 2011 (edited) Good example skeptic, there were so many examples that disprove this i didn't know where to start, hard to think of an animal that does not use male attractiveness to attract females.... almost any animal with good eye sight? This is misunderstanding, I think. The conclusion of the research is that male attractiveness does not have advantage in evolution, no matter it is used to attract females or not. No, not in animals but in humans. I know a lot of ugly men who don't try to improve their appearance. They still manage to get married and have (ugly) children. In the case of humans, I think there is a tradeoff between appearance and intelligence. Good question. But how many people who think themselve not attractive like to be the subjects in such research? Edited February 16, 2011 by thinker_jeff
Mr Skeptic Posted February 16, 2011 Posted February 16, 2011 No, not in animals but in humans. I know a lot of ugly men who don't try to improve their appearance. They still manage to get married and have (ugly) children. In the case of humans, I think there is a tradeoff between appearance and intelligence. No tradeoff. Beautiful people are more intelligent, ugly people less intelligent. (on average, of course) http://www.psychologytoday.com/blog/the-scientific-fundamentalist/200903/beautiful-people-are-more-intelligent-i This is misunderstanding, I think. The conclusion of the research is that male attractiveness does not have advantage in evolution, no matter it is used to attract females or not. It seems to me like the study says the the sexually selected genes do have an advantage but that it is limited and not selected for beyond a certain point.
thinker_jeff Posted February 16, 2011 Author Posted February 16, 2011 It seems to me like the study says the the sexually selected genes do have an advantage but that it is limited and not selected for beyond a certain point. Thanks for the defferent explanation; however, it doesn't contradict my statement. Any of species needs hundreds or thousands of generations to evolve at least.
Ringer Posted February 17, 2011 Posted February 17, 2011 No, not in animals but in humans. I know a lot of ugly men who don't try to improve their appearance. They still manage to get married and have (ugly) children. In the case of humans, I think there is a tradeoff between appearance and intelligence. Humans are animals, we are not 'above' them. People tend to be attracted to people that are at a similar attractive level. There are also other factors, exposure effect and the like, but relative attractiveness is a fair indicator. To add to what Skeptic said attractiveness can not only have a correlation with intelligence, but it also correlates with health, success, etc.
Mrs Zeta Posted February 17, 2011 Posted February 17, 2011 I wonder where the perception that sexy blond women are generally dumb, and ugly scruffy scientists are generally geniuses comes from. Also, what is the evolutionary advantage of dorky (socially inept) teenagers who are computer geniuses. Prove me wrong, show me a beautiful computer hacker.
thinker_jeff Posted February 17, 2011 Author Posted February 17, 2011 I have another question - Why the majority of male animals are more attractive than their females which seems reversed in human beings?
Marat Posted February 17, 2011 Posted February 17, 2011 In humans, could it be the case that traits selected for sexual attractiveness eventually come to be correlated with the genetic predisposition to less intelligence (a.k.a. the 'dumb blonde phenomenon')? It is well-established that initially the human population was brown-eyed and dark-haired, but that people with lighter colors were sexually selected because their unusual appearance made them interesting or attractive. But then, given that these people could be as stupid as they liked and still be sexually selected as breeding partners, since it was not their intelligence but their appearance that was getting them mates, their was no selection for intelligence in this group, but only for blonder and blonder appearance, so their intelligence was selected out.
thinker_jeff Posted February 17, 2011 Author Posted February 17, 2011 My idea is that because of the civilization, human beings are shaved and dressed themselves so that the appearances are reversed.
Mr Skeptic Posted February 17, 2011 Posted February 17, 2011 I wonder where the perception that sexy blond women are generally dumb, and ugly scruffy scientists are generally geniuses comes from. Also, what is the evolutionary advantage of dorky (socially inept) teenagers who are computer geniuses. Prove me wrong, show me a beautiful computer hacker. Sexy blond women are not dumb in general, but sometimes they get a position they don't deserve from their smarts due to being sexy and blond. If so, they could be dumber or less experienced than the average person in that position, even if smarter than the general population. Being unkempt is not the same as being unattractive. It just means they have more important things to do than grooming, such as learning/experimenting. Also being a scientists probably correlates pretty well with being smart. As for knowing about computers, being unsocial gives you a lot more time to learn. And for proving you wrong, how about you read the link I gave.
AzurePhoenix Posted February 18, 2011 Posted February 18, 2011 (edited) In humans, could it be the case that traits selected for sexual attractiveness eventually come to be correlated with the genetic predisposition to less intelligence (a.k.a. the 'dumb blonde phenomenon')? It is well-established that initially the human population was brown-eyed and dark-haired, but that people with lighter colors were sexually selected because their unusual appearance made them interesting or attractive. But then, given that these people could be as stupid as they liked and still be sexually selected as breeding partners, since it was not their intelligence but their appearance that was getting them mates, their was no selection for intelligence in this group, but only for blonder and blonder appearance, so their intelligence was selected out. As part of the thinking goes, many elements associated with an attractive woman are indicators of youth, different elements representing different tactics selected for by either side in the battle of the sexes. Small nose, big eyes, full, shiny hair - all very paedomorphic. Particularly in various European populations, many people are born with lighter hair that darkens as it matures. Perpetually blonde hair could potentially fool potential mates. Among other things, (few traits serve just one purpose) large, firm breasts may serve as an indicator to males of youth by their tendency to sag at a later age, working against the female in her later years, while helping the male avoid wasting his time on lower quality child-bearers. Also, lighter colored eyes make it easier to read subtle cues in the dilation or contraction of the iris. And of course, since humans just tend to be like that, novelty value no doubt makes a strong or even stronger impact on certain traits too. It's not that the male wouldn't happily fertilize below-standard females given the chance, it's just that he'd show preferential treatment and provide greater support to premium mates, who would be more likely to maximize his reproductive success. The thing is, assuming pre-agricultural lifestyles, the novelty of blonde hair would probably not be worth the extreme sacrifice of choosing a stupid mate. Of course nowadays, the Idiocracy-effect could be creeping in from innumerable vectors. Anyhow, blondes have been perceived very differently over the centuries by different societies, so the modern stereotype of the dumb blonde is likely a culturally-driven phenomenon, owing to both generalizations based off of well-known individuals, as well as numerous subtle factors like Skeptic's example. Edited February 18, 2011 by AzurePhoenix
thinker_jeff Posted February 18, 2011 Author Posted February 18, 2011 To AzurePhoenix and other female members, Do you subjetively think that there is a tradeoff between appearance and intelligence in human males? Or any tradeoff between any other characteristics?
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