Evolutionary advantage of X?

nozzferrahhtoo

There is no evolutionary reason for laughter. Its purely a conspiracy of the american corporate machine to make money.

Walt Disney - "Laughter is America's most important export."

Sorry..... Ive been working on the theory that its possible to make, and argue for, a conspiracy theory about just about ANYTHING.

AtomicHorror

nozzferrahhtoo wrote: »

There is no evolutionary reason for laughter. Its purely a conspiracy of the american corporate machine to make money.

Walt Disney - "Laughter is America's most important export."

Sorry..... Ive been working on the theory that its possible to make, and argue for, a conspiracy theory about just about ANYTHING.

Motive seems to be the stumbling block for most. I post on a science forum where there's a user who is convinced that NASA is deceiving the public about the existence of other planets. I've little doubt they could make a good stab at it, but I can't for the life of me imagine why they'd bother.

Same goes for the "atheist conspiracy" currently peddling the lie that is Evolution :pac:

Zillah

AtomicHorror wrote: »

Same goes for the "atheist conspiracy" currently peddling the lie that is Evolution :pac:

We're in service to the devil, duh.

AtomicHorror

Zillah wrote: »

We're in service to the devil, duh.

Is that why I like heavy metal music and games of chance so much?

JC 2K3

The Female Orgasm.

Why?

Zillah

I hear that encouraging mammals to have sex is good for the continuation of their genetic code.

anti-venom

JC 2K3 wrote: »

The Female Orgasm.

Why?

At least you didn't ask, 'the female orgasm, How?';)

AtomicHorror

JC 2K3 wrote: »

The Female Orgasm.

Why?

Reward? Reward sensations are very commonly employed by our brains to encourage behaviour that is in line with survival and reproduction.

failsafe

anti-venom wrote: »

It's not always practical, is it? Given some women's shapes you would need a six inch WIDE langer to make it work!

And thus began the titty w*nk/penis girth evolutionary arms race.

pH wrote:

Given you accept peacock tails were formed by sexual selection, can sexual selection not explain anything with the answer "Just because females liked it"?

pH, that isn't my understanding of the sexual selection explanation. Something other than sexual selection usually kicks something like that off. IIRC it was Dawkins in the selfish gene that explained it something like this (as a possible scenario):
* Many male peacocks were fit enough to last to reproduction age
* If one or two had colourful marking it made them more susceptible to predators
* Therefore, a peacock with colourful markings/feathers who made it to reproductive age must have had kick ass genes to overcome such a big handicap
* Therefore females who were attracted to this handicap ensured that they were passing strong, 'cream of the crop' genes on to their offspring
* This was different to other attractions, as it wasn't something males could fake, i.e. they could grow bones that look like big muscles etc. but they couldn't "fake" being obvious to a predator
* After x amount of generations, females who are attracted to this have the "fittest" offspring, and gradually the "gene for" being attracted to bright feathers becomes widespread in the population. This has 2 further effects (which can spiral) which is what is often referred to as sexual selection:
1. Males without big feathers get laid less and less, and so the gene for feathers becomes more prevalent amongst men
2. Females who aren't attracted to bright colours/feathers produce sons without them, who in turn have a tough time impressing the vast majority of ladies, so they don't make daughters that are unattracted to feathers. So in the interest of having grandkids it does the females well to be attracted to bright feathers.
* This is then free to spiral once it reaches a critical mass because of 1 & 2 above, even though it may not confer an obvious "survival advantage".

Another analogy is to imagine a woman who looks at two men running a 100m sprint towards her (i.e. to reproductive age). If they both arrive at the finish at the same time (survive to reproductive age) but one has a big bag of coal on his back (colourful feathers) then she'd do well to pick him as the "fittest", as he can't really have fooled her about his speed.

This could be similar for breasts (I don't know) in the way that one poster earlier said. It was an advantage for men to be attracted to roundness in females (which led to being attracted to good baby makin' behinds) but once we stood upright females evolved nicer (:D) looking breasts before males lost the attraction to that shape. I'm sure, however, plenty of advantages, such as some mentioned above, must have been present for it to continue to confer advantage.

Incidentally, since we're on the topic (of naughty bits), I think it was Dawkins too who talked about the size difference in a man's erect and non-erect penis, and for the same reason. In an evolutionary sense, getting an erection can be a hard thing to do (pun fully intended). For example, some monkeys just have bones there to do the hard work (sorry, I'll stop now). Like a peacock's feathers, an erection proves something about a man's fitness, strong blood flow, lack of disease/heart problems etc. And, like the feathers, having a range of size demonstrates that "it's all natural" so that females can discern the real mccoy from the fakers. Again it's all men going out of their way to prove their fitness to females, as they get better and better at catching out tricks.

Goduznt Xzst

Evolutionary advantage of.... head hair

Why do we still have head hair when the majority of the rest of our body grows very small amounts of it. Is it a product of sexual selection? Or does it serve some evolutionary need?

The Mad Hatter

Goduznt Xzst wrote: »

Evolutionary advantage of.... head hair

Why do we still have head hair when the majority of the rest of our body grows very small amounts of it. Is it a product of sexual selection? Or does it serve some evolutionary need?

Keeps us warm? We started wearing clothes on the rest of our bodies, but hats much later.

I dunno, this is a complete guess.

Zillah

A huge amount of heat is lost through the head. I presume keeping hair there serves a purpose for heat maintenance.

Goduznt Xzst

Yeah but the hair on our heads also grows indefinitely? What is the purpose of this? natural matting of the hair to form dread locks to provide more insulation?

But humans have not required thick body hair for a long time, if the reasoning for it is for protection from the sun or protection from cold then why do tribes that live under tree cover in warm environs still have head hair?

Is it a case that the bald gene just isn't passed on and that mates will sexually select someone with head hair over someone who's bald? Maybe it is subconsciously viewed as a result of sickness or old age and therefore the mate would not be the best suited at being an effective mate?

Dave!

On the topic of hair -- humans have alot of hair around the genital area, as well as under the arms. From what I understand, sperm production is increased when the testicles are cooler, so pubic hair can't be for keeping the balls warm can it? Then what of armpit hair?

I was thinking that perhaps it reduces friction in the areas. The armpits and groin are probably the areas that have the most movement/friction. I'd be curious to see if the temperature of the groin is on average higher or lower in someone with alot of pubic hair.

As for the head... I'd be inclined to think that it's for heat retention in the brain. Dunno if the evidence supports that though.

anti-venom

Goduznt Xzst wrote: »

Is it a case that the bald gene just isn't passed on and that mates will sexually select someone with head hair over someone who's bald? Maybe it is subconsciously viewed as a result of sickness or old age and therefore the mate would not be the best suited at being an effective mate?

I read somewhere recently that the opposite may be true. Baldness in males may have evolved as a display signal of seniority, virility and dominance thus indicating his suitability as a partner.

failsafe

I don't think reward is a good enough explanation for this. If you look at the alternative, that having sex "feels real good", that would be substantial to reward females enough for reproduction, without needing a climax.

Also, I read that the numbers don't quite support the reward theory. Female orgasm rarely happens through sex alone, and so 'in the wild' where most sex is just a quickie with no foreplay, so the orgasm would not be frequent enough to be the reward for reproduction. If you think about it anecdotally, considering our evolutionary past, both our cultural history before the sexual revolution and the rise of feminism, and considering our animal past, I find it hard to believe all our male ancestors were all Romeos enough to make the female orgasm a regular factor in reproductive success!

The best theory I've heard of is the "happy bonus". It's generally understood that men have nipples, because when we're wee foetuses in the womb, nipples are formed before we differentiate into either a boy or a girl, and so men have nipples because women need them. In much the same way, that naughty bit of sensitive flesh between our legs develops in both girl and boy foetuses in the same way. It then either becomes an out-y in a boy or an in-y in a girl (running between the clitoris and the g-spot). In the same (but opposite) way as nipples, an orgasm is needed by men as ejaculation needs to be a timed event. A good feeling won't suffice for reproductive success; it will provide reward for reproduction, but a climax is needed for the timed, optimal release of sperm. Because of this, women get a climax as a "happy bonus". The female orgasm probably isn't strong/frequent enough to be "selected for", but it has enough positives not to be selected against.

anti-venom

You've been reading your Gould, right Failsafe?:)

failsafe

I've been listening to a podcast of someone explaining Gould! (I'm a slow reader! )

I think I heard that the name of the book was "the case of the female orgasm" is that Gould?

anti-venom

The Case of the Female Orgasm is by Elizabeth A Lloyd. Not that I knew it offhand; I had to google the title. Looks like it might be an interesting read though.

failsafe

Oh, I thought the podcast said that the "happy bonus" was from that book, but I know I heard the name Gould in there too!

The podcast is Evolution 101, if you're interested. It's very very good. Nice 10 min episodes on discussions like this thread. Search for it in itunes or check out his website at http://www.drzach.net/

jtsuited

yeah isn't the female orgasm just the result of stimulation of parts of the genitals that are sort of the same type of buzz as male nipples?

As in, developed in the first stages of foetus development before sex has been 'decided'.

failsafe

jtsuited wrote: »

yeah isn't the female orgasm just the result of stimulation of parts of the genitals that are sort of the same type of buzz as male nipples?

As in, developed in the first stages of foetus development before sex has been 'decided'.

Em... yes?

jtsuited

failsafe wrote: »

Em... yes?

sorry!

redfacedbear

failsafe wrote: »

I don't think reward is a good enough explanation for this. If you look at the alternative, that having sex "feels real good", that would be substantial to reward females enough for reproduction, without needing a climax.

Also, I read that the numbers don't quite support the reward theory. Female orgasm rarely happens through sex alone, and so 'in the wild' where most sex is just a quickie with no foreplay, so the orgasm would not be frequent enough to be the reward for reproduction. If you think about it anecdotally, considering our evolutionary past, both our cultural history before the sexual revolution and the rise of feminism, and considering our animal past, I find it hard to believe all our male ancestors were all Romeos enough to make the female orgasm a regular factor in reproductive success!

The best theory I've heard of is the "happy bonus". It's generally understood that men have nipples, because when we're wee foetuses in the womb, nipples are formed before we differentiate into either a boy or a girl, and so men have nipples because women need them. In much the same way, that naughty bit of sensitive flesh between our legs develops in both girl and boy foetuses in the same way. It then either becomes an out-y in a boy or an in-y in a girl (running between the clitoris and the g-spot). In the same (but opposite) way as nipples, an orgasm is needed by men as ejaculation needs to be a timed event. A good feeling won't suffice for reproductive success; it will provide reward for reproduction, but a climax is needed for the timed, optimal release of sperm. Because of this, women get a climax as a "happy bonus". The female orgasm probably isn't strong/frequent enough to be "selected for", but it has enough positives not to be selected against.

I'm open to correction on this but;

My understanding is that during a female orgasm the womb contracts repeatedly in such a way that pushes the cervix someway down the vagina. the theory goes that in effect the cervix gets dunked into the semen deposited in the vagina and thus draws some of the swimmers up into the womb.

The female orgasm would therefore increase the chances of reproduction and would be a selected evoloutionary trait.

jtsuited

What is the feckin point of Wisdom teeth?

Dave!

Funnily enough I was just reading this wiki page on human vestigiality and it discusses (briefly) wisdom teeth

Dades

According to my dentist I am more evolved because I have no lower wisdom teeth.

Or stupider. I can't remember. :pac:

Galvasean

Here's a live one for ye.

Case: the therizinosaurs, a group of dinosaurs which over time evolved from fleet footed predators similar to 'raptors' into lumbering plant eaters. Falcarias is the earliest known one which displays traits of both carnivorous and plant eating dinosaurs. Anyone care to hazard a guess as to what evolutionary pressures may have brought about such change?

Here is an article on Falcarias
http://chem.tufts.edu/AnswersInScience/therizinosaurs.htm

failsafe

redfacedbear wrote: »

I'm open to correction on this but;

My understanding is that during a female orgasm the womb contracts repeatedly in such a way that pushes the cervix someway down the vagina. the theory goes that in effect the cervix gets dunked into the semen deposited in the vagina and thus draws some of the swimmers up into the womb.

The female orgasm would therefore increase the chances of reproduction and would be a selected evoloutionary trait.

I think the gist of what I was reading was that although something like that is a good bonus that would stop it from being selected against, it is too infrequent to be selected for. So if in a population of early humans, if some females had orgasms, but most didn't, the female orgasm (as we know it today) wouldn't occur frequently enough to confer a selective advantage and be selected for. Most of the time those females had sex, they probably wouldn't have an orgasm.

However, if it happened just because it was selected for in males, it comes with some infrequent happy bonuses that prevent it from being selected against.

That was just the opinion of the article I read. Personally I can see how little things, no matter how infrequent, which can increase the probability of successfull reproduction by even a tiny percent, could become widespread in a population over time.

AtomicHorror

Dades wrote: »

According to my dentist I am more evolved because I have no lower wisdom teeth.

Or stupider. I can't remember. :pac:

"More evolved"? How do you measure that?