How does "sexual selection" without intention of the female mate of having fit offspring, works?

Question

Example: After humans drifted from their closest relatives, chimpanzees, the males began loosing the baculum, and started depending on blood pressure to get an erection.
According to Richard Dawkins, this was due to a "sexual selection" from females because an erection having an hydraulic mechanism in the penis would mean that the individual has good blood pressure, and doesn't have stress or other mental issues. How did early female humans "chose" the me until they lost the baculum, without showing purpose (remember that evolution is not driven by purpose)?

Come on, guys!

Answer 1

Despite the baculum all mammalian penises are erectile. The bones have a complex hormonal control pattern. They share may genes and sequential gene networks that produce and develop limbs. There is a faciogenital dysplasia Aarskog syndrome that shows this correlation. Given the existence of one such shared regulator there may have been others. This shared use of a gene is often regulated in a tissue specific manner. Perhaps shifting to an up right posture in bipedalism also involved a shift in baculum. Loss of bone could drop a limit in how the knee was able to flex and lock upright. Those males with reduced baculum who also had a stronger erectile function would have suffered less from loss of baculum but also had the benefit of the posture shift. This kind of pleiotropic effect could account for the dual bony changes that occurred in humans.
http://books.google.com/books?id=B8ooFVfNsLAC&pg=PA329&lpg=PA329&dq=human+bipedalism+baculum+loss&source=web&ots=-TNt3WrAIX&sig=AxktD8vKa1_FvdQR5mzy9CXH6GU
My guess is sexual selection would be well down on the selective pressures on something so integral in reproductive success as the baculum.

Answer 2

Consider a key point. As humans (1) walked upright; and (2) were increasingly hairless; the human male's equipment was particularly exposed. This meant both that it was vulnerable during daily activities (like hunting); and far more visible to females than in quadruped mammals, (including other primates). So Dawkins' point is that it is as visible an indicator of the health of the male as are other secondary characteristics (broad chest, big chin, facial hair, symmetrical features, etc.) that we commonly associate with sexual selection.

So the way it would work is that if some males had a smaller baculum, but still had the same sized erection, then the visible signs would be a more pronounced *difference* between the non-erect and erect state. I.e. the fellas with the big baculum would appear in a constantly erect state pointing up along the belly, while without the baculum, it would hang down and out of the way. Females could see this, and prefer it. Females may have been more aroused by males that themselves were better able to show arousal (instead of appearing to be in a constant state of arousal).

I would also put my money on the different hypothesis that a baculum is a *disadvantage* in an upright biped, making the penis a bit more vulnerable to damage during the already dangerous lifestyle we guys were probably already leading. So it was less a matter of sexual selection by the ladies, and more a matter of avoiding damage to Mr. Happy ... or just the inconvenience of having him at full staff ... when hunting bison.

Or more likely, it was a combination of both. A big baculum put the penis in harm's way for a biped, and so the baculum became smaller, but this required more and more hydraulic means (blood pressure) to maintain erections during courtship and mating. This in turn became a secondary characteristic that females would look for ... and so the hydraulic machinery got better and better, while the baculum got smaller and smaller, eventually disappearing altogether as the hydraulic mechanism was all that was needed.

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P.S. Why did Pfizer come up with the name "Viagra" ... they could have called it "Bacula" ("to get you 'back' in the saddle" ... or "honey, count Bacula is back!")

Answer 3

Well - in Fem War II (a developing Grappler book/series) Mabel B and Mabe are our prime machine gun team, and you and Neo are the backup team... I offer women privilege and more than equal billing right there - even in the midst of The War to End All Feminisms.... a war which, according to Fem War II, will be won by the exercise of both men's and women's personal power to choose to fight against that which is attacking them and their country. He's right, you know. All this guff about 'male privilege' falls on the one single point raised by Tea - I think it was - the 'norm' in society being 'the white middle class man' - a relatively small minority indeed. Thus the extrapolation of this alleged and totally unproven privilege to ALL men everywhere is a nonsense even within feminist folklore. Not only that, but it clearly shows what many have been saying all along - 'feminism' is a middle class grab for power and privilege by an already privileged group of women - not anything at all to do with the escalating plight of the REAL women out there.