Survival of the most attractive?

[Egg]

Is there any evidence which suggests that peacocks with bigger tails are, on average, more healthy/fertile than peacocks with smaller tails?
Or are people just assuming this to be the case?

Apparently there's a study (Moller and Petrie) which showed some correlation between higher immunity and tail size.

Then again, if that's the case, then peacocks aren't a good example of what I was asking. Of course its possible that all attractive features signify something that would aid survival of the species which would make the most sense or they could possibly just be left overs from something else or some mutation that had no significant effect on survival.

There does seem to be a lot of these kinds of features in nature though and I have heard biologists putting forward the notion of attractiveness alone being a factor in evolution.

 

[CapelDodger]

I don't think that's the claim. It isn't necessary for bigger tails to mean healthier, it's enough that big tails means healthy. The bigger part just makes that assesment more obvious to the female.

It also means that come the next major extinction, they're all toast. Elaborate display is an indulgence of easy times.

 

[Egg]

Consider the "founder effect": a pregnant female gets washed up on the beach on an island where none of her kind have ever existed. Her progeny may carry traits that are irrelevant to life in the new environment. But if those traits are targets of sexual selection, they may persist despite no longer having any utilitarian value.

Well that would make a lot of sense and I'm sure there must be plenty of examples of animals which continue to be driven by attraction to obsolete features after their environment has changed. I would have thought that in most cases where this occurs, the change in environment would be relatively recent (in terms of evolution) otherwise what they find attractive would have adapted to their new surroundings.

 

[Dogdoctor]

Genes favoring intelligence would be difficult to imagine. Without language it is hard to evaluate the intelligence of a potential mate. Therefore it would be highly unlikely for a gene to exist favoring intelligence.

 

[CapelDodger]

To be a singer or poet requires high intelligence (and specifically high verbal fluency, which is of course part of intelligence).

I would say a certain type of intelligence, just as the ability to learn physical skills is a type of intelligence.

As a matter of fact, it's hard to judge "intelligence" in any other way than through behavioral observation.

Quite. And fast-talking charmers do get laid. Language and poetry are our peacock feathers; fortunately for us (so far) language is a productive adaptation in itself.

 

[CapelDodger]

Genes favoring intelligence would be difficult to imagine. Without language it is hard to evaluate the intelligence of a potential mate. Therefore it would be highly unlikely for a gene to exist favoring intelligence.

Without language you can assess the success of a potential mate, and amongst the great apes idiots don't prosper. Nor, when male, get laid much (if at all).

 

[CapelDodger]

Do you have any evidence for this? I find it quite an odd statement, but I am interested in what support there is for it

I too am surprised and intrigued. Bringing home the bacon (or at least promise of bringing home the bacon soon) strikes me as far more influential than the conformation of the wedding-tackle. If the bacon-guy turns out infertile or incapable, there's always the pool-guy or the gamekeeper; a younger brother or close cousin of hubby is the safest option. Bacon-guy still comes up with the bacon for the kids.

 

[Dogdoctor]

Without language you can assess the success of a potential mate, and amongst the great apes idiots don't prosper. Nor, when male, get laid much (if at all).

Idiots are identified by an IQ test? Where do you get this from?

 

[CapelDodger]

Idiots are identified by an IQ test? Where do you get this from?

Where do you get that from ?

eta : If you want to get into a dog-off, your dog's got the stare but my dog's got the mayor.

 

[Dogdoctor]

Where do you get that from ?

eta : If you want to get into a dog-off, your dog's got the stare but my dog's got the mayor.

Not meant in a bad way. What data did you use to arrive at your position?

 

[articulett]

It's not survival of the prettiest... it's survival of the best reproducers (along with the traits that aided the process)... We've evolved to "see pretty" in things that it's evolutionary advantageous to see as "pretty". We see animals that resemble human babies as "pretty" whereas insects... not so much. We see pretty in the colorful, because ripe colorful fruit and bright red lips and so forth are beneficial to survival and reproduction...we have a broader range of colors than most animals--as do most birds because those who had so survived preferentially--we could see ripe fruit better and such. What humans find attractive in general is due to having ancestors that preferentially survived and reproduced by having similar attractions.

Human Penises are much larger than other primates... there are evolutionary reasons for this just as there are evolutionary reasons for all physical traits.

Here's a tidbit: http://www.associatedcontent.com/article/42665/penis_evolution_intersexual_and_intrasexual.html

You should see what's going on with duck genital evolution... it isn't pretty to me... but who am I to judge... http://www.nytimes.com/2007/05/01/science/01duck.html

It's backwards to think "survival of the prettiest or sexiest"-- what actually is going on is that humans that develop preferences for certain traits in a mate, have more offspring that survive to reproduce than those who don't...men that have the most offspring pass on their traits preferentially as do women who have the most offspring that survive to produce more offspring. Females evolved to be the choosier sex in most species because their offspring's survival depends on them being good choosers.

And yes, Capel Dodger, it has long been thought that language has evolved along with poetry and music because women selected these traits in men... and they were more likely to have children who had these traits which turned out to be the number one ways humans learn and communicate-- before that, there was just imitation and our evolutionary programming.... all based on urges and feelings... but we evolved others strategies to pass on knowledge via feelings-- and those who preferred mates that had these gifts, had offspring with a survival/reproductive advantage--and the ability to plan ahead, manipulate, deceive, have goals, etc..

It really isn't "survival of the fittest"-- it's survival of the genes that are best at getting themselves copied. Venereal diseases survive by riding along other animals' evolutionary primal instincts (humans are far from the only animal with venereal diseases, btw). It has nothing to do with the fitness or prettiness of the bacteria involved... just the fact that they've evolved a strategy to get their genes passed on... and animals evolve strategies to deal with their parasites strategies and so on. It's an evolutionary arms race and we see pretty where it was advantageous to see pretty. We see yucky and scary in things which it was evolutionary advantageous to find yucky or scary.

If the man with the larger genitals averages more offspring then the man with the smaller one... for whatever reasons... then that drives male average genital length. If the man who is the smoothest talker passes on his genes preferentially, offspring become increasingly smooth talkers and women who prefer those with such traits are more likely to have reproductively successful offspring. Our entire genomes are all based on eons of ancestors that won the competition in passing on their genes.

 

[Dr. Trintignant]

A common example used is the peacock. The point raised is that the bigger and more illustrious the peacock's tail is, the more likely he is to attract peahens and therefore pass on his genes.

The peacock is likely a result of the "handicap principle".

In this interpretation, the point of the tail is that it's a waste. In human terms, it's an "ostentatious display of wealth". It's not just a display that the bird is healthy--it's that the peacock is so healthy, well beyond the requirements of its environment, that it can afford to waste resources on useless displays.

Of course, an animal can try to "lie" to potential mates about its fitness in various ways. That's why it's so important that the trait is a legitimate physical handicap. Anything else would be too easy to fake.

- Dr. Trintignant

 

[articulett]

Yes, but the peahen, doesn't have to see it as health... she just has to evolve a tendency to be attracted to a certain look-- and that look just has to be a general indicator of health... Finches will preferentially mate with the male with the brightest red beak... it's a good genetic algorithm because it's a simple rule that more often than not, indicates that the bird his healthier than average (consumes more beta carotene)-- But no female bird needs to know why they are attracted to certain things. We evolved to find things that happen to make healthy babies "sexually attractive"-- no creature has to know how to make babies to make them... they just need to have evolved urges and preferences that encourage them to do what needs to be done to pass on and refine those urges and preferences in the DNA of the next generation.

Yes, they evolved because they are displays of "wealth"-- "excess"-- but no peahen needs to know that. Humans who understand evolution and basic game theory will use these terms to explain how it is that peacocks have come to look so ostentatious. They say there is no accounting for taste... but there are actually some pretty strong evolutionary reasons why tastes evolve... and, while they may seem irrational, there is a rational explanation for what appears absurd and irrational once you understand the basics of evolution.

Not only were longer necked giraffes better at getting food and fighting for mates (they use their necks to fight), but females who preferred longer necked mates had more offspring that survived due to their own longer necked genes. "Long necks" are sexy to female giraffes because giraffe females that found them sexy had more surviving offspring! Survival of the best reproducers is the real key to understanding evolution. The question to ask, is why certain preferences and bizarre features were preferentially selected and honed over time... what is the genetic advantage to having such traits selected?

 

[fishkr]

what actually is going on is that humans that develop preferences for certain traits in a mate, have more offspring that survive to reproduce than those who don't...men that have the most offspring pass on their traits preferentially as do women who have the most offspring that survive to produce more offspring. Females evolved to be the choosier sex in most species because their offspring's survival depends on them being good choosers.

If I may suggest a small refinement to your otherwise clear statement, female humans are choosier than males because of a number of factors, but most central of all to behavior seems to be the extremely long dependancy period of human infants. This biological condition drives plot and sub-plot in the reproduction game.

Human females, interestingly, are often un-choosy under many conditions, which is confirmed by the somewhat surprising symmetry of rates of human infidelity between the sexes.

It's a fascinating, well sudied, topic. My favorite lay-person's book on the subject is Robert Wright's "The Moral Animal".

M

 

[articulett]

I agree... my phrasing bugged me too... thanks for cleaning it up. I was trying to explain why female selection drives the evolution of species where the offspring need parental investment... even if it's just sitting on a clutch of eggs.

Moreover, I wanted to add that tendencies across groups don't mean that there isn't great variety in individuals... variety comes from recombinations and mutations-- which "natural selection" then selects from for further refinement and honing. What we observe is eons of such tweaking being tested via natural selection over time... but the selection process is on going... there is no "end point" so long as something is passing on it's DNA into future generations.

 

[bpesta22]

Genes favoring intelligence would be difficult to imagine. Without language it is hard to evaluate the intelligence of a potential mate. Therefore it would be highly unlikely for a gene to exist favoring intelligence.

There are many other reasons why IQ might be selected for beyond just impressing a mate. Survival, for example, might co-vary with how fast one can process information in his/her environment.

 

[fishkr]

Genes favoring intelligence would be difficult to imagine. Without language it is hard to evaluate the intelligence of a potential mate. Therefore it would be highly unlikely for a gene to exist favoring intelligence.

"Genes" don't "favor" intelligence. Last I checked they have no will of their own. Selection favors adaptive/successful behaviour or characteristics by The Process. What are you talking about?

 

[Dogdoctor]

"Genes" don't "favor" intelligence. Last I checked they have no will of their own. Selection favors adaptive/successful behaviour or characteristics by The Process. What are you talking about?

It was suggested that there may be a genetic tendency to select for intelligence for a mating partner and this would be inherited as a evolutionary advantage. I was mentioning that it seems unlikely. Of course maybe I misunderstood but that is still my thoughts about the issue regardless if anyone else was talking about it or not.

 

[Dogdoctor]

There are many other reasons why IQ might be selected for beyond just impressing a mate. Survival, for example, might co-vary with how fast one can process information in his/her environment.

I know there is a bunch of people scientist even who are trying to predict the behavior of genes that they have no clue about. They don't know if the genes follow simple Mendelian inheritance patterns or if the genes have more than one effect or basically anything about the genes. That doesn't stop them from trying to imagine how they might interact on an evolutionary scale of things. Ok so you can theorize how it might be useful so can I but what I can't do is tell you how does an organism recognize intelligence? I say that isn't likely any force at all in evolution because there is no realistic way for one organism to judge another organisms intelligence.

 

[fishkr]

I agree... my phrasing bugged me too... thanks for cleaning it up. I was trying to explain why female selection drives the evolution of species where the offspring need parental investment... even if it's just sitting on a clutch of eggs.

Moreover, I wanted to add that tendencies across groups don't mean that there isn't great variety in individuals... variety comes from recombinations and mutations-- which "natural selection" then selects from for further refinement and honing. What we observe is eons of such tweaking being tested via natural selection over time... but the selection process is on going... there is no "end point" so long as something is passing on it's DNA into future generations.

And to the original post, vis a vis high human MPI in this story, women tend to select for males that promise resource yield and stabilty, yet tend to "outsource" DNA (postman, etc.) probably a hedge against choosing and over-investing in the Surf Stud Turned Xerox Salesman phenom.

I ring twice, on occassion BTW.

M