Most people think that evolution is all about the “survival of the fittest.” This is incorrect. It is about the “survival of what didn’t kill the organism or cause the organism to be killed.” As a result animals, including modern humans, are mish mashes of advantageous features and features which have no advantage and no real purpose, but don’t get in the way.
My contribution to the list I hope we assemble is the prominent chin on modern humans. Vertebrates got on fine without them for hundreds of millions of years. Even our closest relatives lacked protruding chins. So why do we have them? I dunno, but my best guess is that one guy had one, the ladies swooned, and lots of little Cary Grants were born. Then one of those evolutionary bottlenecks reduced the human population to mostly members of the Cary Grant tribe and Bob’s your uncle, here we are, sharing a feature with the only advantage of getting one caveman laid.
Can you think of other useless crap that missed Evolution’s merciless scythe?
Not entirely true. Selection of mates is a huge factor in natural selection, and seems to be the relevant one here.
There are theories as to the ontogeny of the human chin, one says it facilitates speech, one says it makes it easier to chew, and another says it helps with balance when we are upright. People who speak better have an advantage both for survival and reproductive purposes. People who chew better might whine less about their gums, and therefore be slightly more attractive as a mate. We could speculate all day here, and if you are really interested I’m sure we could dig up some cites.
THis is the idea delaying of physical development so that young looking organisms are able to reproduce.
I think it is a greater and complex evolutionary advantage to delay our physical development as we grow…it allows us big brains, long juvenile times which translates into long periods of time when learning is at its peak.
No, it’s about “traits which lead to reproduction”. Any traits that allow the organism to survive at the expense of reproductive fitness will not be selected for. Any traits that do lead to reproductive success at the expense of overall fitness WILL be selected for. The classic example is the peacock’s tail, which reduces the bird’s overall fitness but attracts the peahens like crazy.
When trying to determine the gender of a skeleton. A male jaw bone tends to have a uniform curvature and thickness at the lower edge (for maximum strength, I suppose.) A female jaw is often thinner at the chin in profile, and has a flattening right at the underside of the chin, making it weaker than a male’s, and where soft tissue accumulate. That’s why women have soft chins. It’s also easy to spot a trans by looking at his/her chin.
I practiced judo before and people who easily gotten choked on the ground were those who either had long necks, or small chins. It’s a matter slipping your forearm from behind in and under his chin to apply pressure on his neck. Bending one’s head forward so as to make your chin touch your upper chest will help to defend against that.
I submit that the flaw I your argument isn’t that it got one caveman laid, but a whole succession of them, where they were chosen by discriminating cavewomen over competing Chinless Wonders. And that, in fact, the trend continued long after cavemen days. That’s how sexual selection works. If it didn’t, eventually the Chinless Wonders would eventually be successful enough to make chinlessness as common as prominent chins.
We’ve got significant chins because it has some advantage in Natural or Sexual selection. I opt for the latter.
And it’s not just prominent chins. People have expressed an interest in cleft[ chins, as well.
I agree with Desmond Morris ( who, before he started writing books about humans, was an animal behaviorist ) that the human nose and cleft chin represents a powerful penis-and-scrotum mimic
Why else value the prominent cleft chin in men , and scorn it in women (nobody sings the praises of a strong cleft chin in women. Or of a large nose, Barbra Steisand notwithstanding)
In other words, survival of the chin isn’t pointless. A pointed chin has a point.
