“Chin-tastic!” ~Crimson Chin
~Max
What flaw? May I remind you:
The implication being that subsequent generations of cavegirls found it hot and wanted a boy just like the boy that married dear, old mom.
Interesting Just So Story, and those become testable hypotheses. I like it, but it needs testing. Toxylon, hold my beer. Cal, stand right here. 
I have nothing to add to the discussion, but will just offer that every time I see this thread title, I do a double-take, because I think it says
“China, evolution, and pointless survival”
Yeah, I need reading glasses, but I’m putting it off as long as I can.
How does that work when the default male state seems to be “bearded”?
When I read the title my first thought seriously was: “What does the millions of Chins have to to do with evolution and pointless survival?” 
I thought it was going to some rant about how the Chinese are taking over the world! :smack:
It seems like I remember watching a documentary about how the jaw/chin moved forward after proto-humans started cooking food,and something about this allowed the brain to increase in size do to the lack of having to have bigger jaw muscles? Something along those lines.
Ahh…I remember seeing that too!
A quick google search for “cooked food increased brain development” and “cooked food decreased mouth size” brought up the folloiwng:
Here’s an article talking directly about mouth and teeth size possibly being linked to cooked food.
"The Shape of the Matter
Over the course of the last few thousand years, the human jaw has changed shape dramatically. One of the broadest trends has been a steady decline in the size of the jaw. From around 35,000 years ago to about 10,000 years ago human jaws and teeth decreased in size by about one percent every 2,000 years. For the last ten thousand years, that pace has increased to roughly one percent every 1,000 years. In pace with our shrinking teeth and jaw, the structure of human teeth has changed as well, as thickening enamel and adaptations in technology have cut back our reliance on strong, well-ordered teeth.
Cooking has had one of the largest effects on the development of human dentition. In the distant past, when much of our diet was raw fruits and vegetables, we needed strong and straight teeth. These helped us push our way through the tough, large particles that made up our diet. Cooking has reduced our need for this ability dramatically. At its simplest, the primary goal in cooking food is to break down tough fibers in meats and vegetables, rendering our meals proportionally easier to digest. As a result, the evolutionary pressure to keep our teeth well-ordered has dropped away."
Source: https://www.ecpi.edu/blog/evolution-teeth-how-smarts-skill-changed-human-mouth
And this article discusses how eating cooked food may coincide with the increase of brain size:
“Fossils show the teeth and digestive tract of Homo erectus decreased in size around the same time brain size increased. This evidence likely means our ancestors started eating softer, higher-quality foods (although not necessarily cooked). New archaeological research has also continued to push back the earliest known date for the control of fire.”
My Google-fu is STRONG! 
Must be all the cooked food I eat! LOL!
Don’t want to have TOO much of a protuding chin. Surely you’ve heard of the Habsburg jaw?
I’m but a gnawer(is that a word?) of rawhide scraps compared to your skills, lol
I think “incomplete” is more accurate than “incorrect”. Evolution by natural selection is indeed all about survival of the fittest (adaptation). But your point is that evolution is not just about natural selection. Evolutionary traits may also arise randomly, through genetic drift. They may evolve by drift if they are neutral to fitness; they may even evolve by drift if they do “get in the way”, if they confer lower fitness. This is more likely to happen in small populations, in which random fluctuations in allele frequencies have a greater effect; natural selection is more likely to remove deleterious traits in large populations.
Traits that are not adaptive in themselves may also be indirect by-products of other adaptive traits. And there’s a word for this, coined by Gould & Lewontin, an evolutionary spandrel.
I know what you mean, but your terminology is a bit off here. There’s only one kind of fitness. Evolutionary fitness is, by definition, reproductive success (greater genetic contribution to subsequent generations). So you can’t talk about “reproductive fitness” vs “overall fitness”. It would be better to say “reproductive success” vs “survival”.
But you’re talking about adaptive traits here, about natural selection and sexual selection. Dropzone’s main point is that some traits are not adaptive at all.
But you also can’t just dismiss the possibility that the chin is not adaptive at all (although I concede that seems unlikely).
The beard is probably so the chinless dudes can get laid too.
My WAG: As the teeth got smaller and the jaws adapted, the chin simply didn’t follow since there was no selective advantage in doing so.
I just find it hard to believe that early humans were choosing mates based on chins. We’re they sitting around at le club Savanna flirting with only the big chins? Seeing how the ideal image of beauty has changed over just the last hundred years, doesn’t seem like an aesthetic feature would change the whole trajectory of human development.
It isn’t really a protruding chin but rather a mid face deficiency. One can tell by the profile, normal is convex theirs is flat or concave. Like Jay Leno, a flat face, the chin is where it should be, the area in the middle third of the face is not far enough out.
Chins do strike me as a remnant of a muzzle, like those still present in our chimp brothers. That is, they’re more atavistic than the more derived receding chins in other homo species. We as humans seem to have a hard time thinking we’re not the furthest from primitive as any great ape gets.