Males are simple creatures

O

Orleander

OH JOY!!!!
Valued Senior Member
Why the hell wasn't I taught this in school???? :mad: It would have explained so much!


The secret to why male organisms evolve faster than their female counterparts comes down to this: Males are simple creatures.

In nearly all species, males seem to ramp up glitzier garbs, more graceful dance moves and more melodic warbles in a never-ending vie to woo the best mates. Called sexual selection, the result is typically a showy male and a plain-Jane female. Evolution speeds along in the males compared to females.

The idea that males evolve more quickly than females has been around since 19th century biologist Charles Darwin observed the majesty of a peacock’s tail feather in comparison with those of the drab peahen.

How and why males exist in evolutionary overdrive despite carrying essentially the same genes as females has long puzzled scientists.

New research on fruit flies, detailed online last week in the journal Proceedings of the National Academy of Sciences, finds males have fewer genetic obstacles to prevent them from responding quickly to selection pressures in their environments.

"It’s because males are simpler," said lead author Marta Wayne, a zoologist at the University of Florida in Gainesville. "The mode of inheritance in males involves simpler genetic architecture that does not include as many interactions between genes as could be involved in female inheritance."...
 
Females have more to lose, they need the energy for growing and raising the young. Males can afford the extra effort required in mating displays, and in so doing provide an outward measure of their genetic health.
 
Actually, Wayne could well be right. I'm working on a new concept in phenotype-genotype architecture related to this.
 
i think its worse than that. men are an afterthought. something to do with chromosomes. its like there is no real reason to be. maybe i exaggerate. lemme track down what prompted this thought. wonder if it should hold true across other species as well
 
Interesting. We actually talked about something similar in one of my genetics courses. Apparently, biologically, males of almost every species are the showier sex, such as the peacock feathers and mating dances mentioned before. However, humans are the only species in which the females are observed to be the more gussied up of the genders (by choice, not biologically). Any ideas why that would be given Wayne's statements?
 
The faster, showier and more attractive ones are simpler? I would think the opposite is true.
 
Funny - buy last I checked - males and females of a species still shared the same genome. So, what is the basis of the statment "they are more simple?"

If I understood my courses in genetics and animal behavior- the "showiness" of either sex is due to sexual selection pressures and balanced by natural selection (ex: the Betta splendens would never survive in the wild with the Betta plakatt because that pretty, "showy" tail is a big target). Ideas about the advantage of being a showy male or female are worked-out but difficult to quantify. Thus, they remain in the world of statistics.

Uh, let me get to the point. Yes, in most species the female invests more. At the very least she will invest more in the gamete. However, there are plenty of species in which the male invests the most in parental care and where neither parents invest at all except at a gamete level (take an Icthyology course and see). So, it would be unwise to write-off males of any species as quicker to adapt to anything based on an assumption that they are simpler. At best, the difference would have to lie only in what was coded on the male sex chromosome. At worst it is egocentric.

Even Wayne qualifies her statements with: ""The mode of inheritance in males involves simpler genetic architecture that does not include as many interactions between genes as could be involved in female inheritance."


If one evolves faster than the other then it would be because the selection pressure was higher. If you want to be egocentric - males evolve faster (note: the author was specifically referring to sexual selection) because females tend to be more picky than males.
 
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linscomb said:
Even Wayne qualifies her statements with: ""The mode of inheritance in males involves simpler genetic architecture that does not include as many interactions between genes as could be involved in female inheritance."
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Well, there's already preliminary evidence for increased variance in female genomic interactions; in a couple of species anyway. I'd post more about it here but I can't. Sorry. :(

But I think females might gain more from diversification through bet-hedging. Males, possibly being less tied to environmental quality, might perceive environmental variance as more fine-scaled than females.
 
linscomb said:
If I understood my courses in genetics and animal behavior- the "showiness" of either sex is due to sexual selection pressures and balanced by natural selection (ex: the Betta splendens would never survive in the wild with the Betta plakatt because that pretty, "showy" tail is a big target). Ideas about the advantage of being a showy male or female are worked-out but difficult to quantify. Thus, they remain in the world of statistics.
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Having some showy yet impractical trait is a sign of fitness. It implies that the individual is so fit it can survive despite the huge disadvantage of a gigantic tail or whatever.

In humans, the tendency of males to engage in stupid and risky behaviors amounts to the same thing. Females love "dangerous" men. Why? Because they continue to survive despite behaviors that increase their likelyhood of death (drinking, smoking, fighting, driving fast, being a firefighter, etc)

Basically every trait defined as 'manly" is dangerous to your health. Women are attracted to this for the same reason female peacocks are attracted to dudes with the giant tales.

The female of the species chooses who to mate with, the males compete to show their fitness. In humans the competition is for wealth, power, and manlyness. In peacocks it's for giant tails. Obviously the sex forced to compete to mate will evolve more quickly. It has nothing to do with genetic simplicity.
 
..."increased genomic interactions" - that one I can buy. More and varied types of genomic interactions could be used to describe the female as more complex.

Also, there might be something to the idea that the female is more conscientious about the quality of the breeding environment - but it seems counterintuitive. Usually the male is setting up the breeding space - be it nest or lek - and the female is choosing the male. Thus - the male is usually exposed to greater pressure from sexual selection. Why? The increased energy investment in (at the least) the gamete means the female has more to lose.

However, there are exceptions to everything...

madanthonywayne said:
Having some showy yet impractical trait is a sign of fitness. It implies that the individual is so fit it can survive despite the huge disadvantage of a gigantic tail or whatever.
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No, fitness, by definition, is reproductive fitness. The more children one has - the more fit.

Having a showy yet impractical trait that is common in the species is a sign that there is sexual selection going on for that trait.
 
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..."increased genomic interactions" - that one I can buy. More and varied types of genomic interactions could be used to describe the female as more complex.
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Agreed. I think though that you guys are confusing variability in reproductive fitness with variability for non-reproductive fitness. I just sent a paper to Marta Wayne on variability in non-reproductive fitness and from her short response it sounds like this is at least partially what she's referring to. Fuck I haev to get these papers out. Seems like everyone's catching on to my little hypothesis here.

You can have fitness specifically related to the act of reproduction, though. High sexual reproductive fitness is an alternate fitness strategy, contrasted to survivorship and persistence.
 
I would be interested in reading the papers.

The variablilty in non-reproductive traits to achieve higher reproductive fitness (stabilizing sexual selection on a trait) seems to be what the "good-genes" theory is trying hard to quantify. If you have a unique take on the current thoughts - let me know if you get them published, please.
 
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Lemme think about it. I kinda want to preserve my anonymity. Sorry I shouldn't have said anything - now I can't back it up.
 
Except if they're ZW female / ZZ male types like birds. Some herps I think too. I've got a polygenic I'm working on now; probably never publish it though.
 
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