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Almost every mammal has a protruding mouth to help bite/feed. Humans are the exception and pre-humans like australopithecus had very prominent mouths like other

Almost every mammal has a protruding mouth to help bite/feed. Humans are the exception and pre-humans like australopithecus had very prominent mouths like other mammals. It seems very likely that chins are remnants of having much longer jaws which have recently (evolutionarily speaking) shrunken. Why do so many people have crooked teeth and need to remove their wisdom teeth? To me, it seems more than likely that is due to the same mouth shortening (or whatever you call it). Teeth disappearing in coordination with shrinking jaws did not happen so it's quite possible chins didn't either. I know there is no proof of this. But we accept many things as true because it seems very likely. I think chins fall into the same where the above explanation should be accepted as probably true until proven otherwise. Other explanations just don't seem nearly as plausible. Even the 'attractiveness' argument doesn't seem compelling to me as you're talking about every society on earth. Did every community of humans on every continent find chins attractive? Not likely.

deleted 11y ago
[deleted]
dalke 11y ago
The shrunken jaw hypothesis was discussed towards the end of the piece: > A different explanation portrays the chin as a bit of the jaw that got left behind while the rest shrunk back. As early humans started cooking and processing our food, we made fewer demands upon our teeth, which started shrinking as a result. They gradually retracted into the face, while the part of the lower jaw that held them did not (or, at least, did so more slowly). Hence: chin. > Stephen Jay Gould and Richard Lewontin, who coined the concept of evolutionary spandrels, liked this hypothesis. So does Nathan Holton from the University of Iowa, who studies facial evolution. “It seems that the appearance of the chin itself is probably related to patterns of facial reduction in humans during the Pleistocene,” he says. “In this sense, understanding why faces became smaller is important to explaining why we have chins.” > “But why did the lower border of the jaw also not shrink?” Pampush asks. It then elaborates on the diversity of hypotheses: > It may seem frustrating to have so many imperfect competing hypotheses, but that's part of the joy of chins: They reveal something about how scientists think about evolution. Some see the sculpting power of natural selection in everything, and view chins as surely some kind of adaptation. Others see natural selection as just one of many evolutionary forces, and so gravitate towards a spandrel-based explanation. “The chin is one of these rare phenomena in evolutionary biology that really exposes the deep philosophical differences between researchers in the field,” says Pampush.
- robotcookies 11y ago
  I realize that it was discussed in the piece and never claimed it wasn't. My claim is only that the argument is more likely than the other arguments (with supporting bits about teeth added in).
  - dalke 11y ago
    My apologies.

deleted 11y ago

[deleted]

dalke 11y ago

The shrunken jaw hypothesis was discussed towards the end of the piece: > A different explanation portrays the chin as a bit of the jaw that got left behind while the rest shrunk back. As early humans started cooking and processing our food, we made fewer demands upon our teeth, which started shrinking as a result. They gradually retracted into the face, while the part of the lower jaw that held them did not (or, at least, did so more slowly). Hence: chin. > Stephen Jay Gould and Richard Lewontin, who coined the concept of evolutionary spandrels, liked this hypothesis. So does Nathan Holton from the University of Iowa, who studies facial evolution. “It seems that the appearance of the chin itself is probably related to patterns of facial reduction in humans during the Pleistocene,” he says. “In this sense, understanding why faces became smaller is important to explaining why we have chins.” > “But why did the lower border of the jaw also not shrink?” Pampush asks. It then elaborates on the diversity of hypotheses: > It may seem frustrating to have so many imperfect competing hypotheses, but that's part of the joy of chins: They reveal something about how scientists think about evolution. Some see the sculpting power of natural selection in everything, and view chins as surely some kind of adaptation. Others see natural selection as just one of many evolutionary forces, and so gravitate towards a spandrel-based explanation. “The chin is one of these rare phenomena in evolutionary biology that really exposes the deep philosophical differences between researchers in the field,” says Pampush.

robotcookies 11y ago
I realize that it was discussed in the piece and never claimed it wasn't. My claim is only that the argument is more likely than the other arguments (with supporting bits about teeth added in).
- dalke 11y ago
  My apologies.