19 votes

Why prehistoric humans needed no braces: Crooked teeth are a modern phenomenon and a telltale sign of an underlying epidemic

13 comments

  1. [7]
    Kuromantis
    Link
    There's also this much longer article by scientific American in this issue. This article basically argues that teeth and jaws evolved for a hunter-gatherer diet and our modern diet means either...

    There's also this much longer article by scientific American in this issue.

    This article basically argues that teeth and jaws evolved for a hunter-gatherer diet and our modern diet means either the jaws are underdeveloped or the teeth grow too large (or both) and so our teeth problems are modern (as in since the industrial revolution). The aspect of the article I found interesting is the implication that big, traditionally masculine jaws are desirable for evolutionary reasons rather than cosmetic ones, for reasons that pertain to both sexes.

    9 votes
    1. [2]
      elcuello
      Link Parent
      Isn't that the case with other traits that's desirable? Like wide hips in women for better births etc. I don't know but it seem like every desirable trait always end up being evolutionary somehow.

      The aspect of the article I found interesting is the implication that big, traditionally masculine jaws are desirable for evolutionary reasons rather than cosmetic ones, for reasons that pertain to both sexes.

      Isn't that the case with other traits that's desirable? Like wide hips in women for better births etc. I don't know but it seem like every desirable trait always end up being evolutionary somehow.

      4 votes
      1. teaearlgraycold
        Link Parent
        One of my hypotheses is that human sexuality is so complicated because of over-fitting. By the nature of evolution, sex is key to trait selection. What we end up with is a brain that has been...

        One of my hypotheses is that human sexuality is so complicated because of over-fitting. By the nature of evolution, sex is key to trait selection. What we end up with is a brain that has been evolved to desperately find any pattern it can to help our genes replicate. This means humans (and possibly other creatures that reproduce sexually and have large brains) end up with all sorts of kinks that have no benefit to evolution. Our brains are just hoping that some of these moon-shot desires end up giving us an advantage.

        A lot of these kinks ended up making sense and have stuck around. People tend to find fitter humans attractive. Wider hips are usually considered more attractive, etc. But you also have a whole field of unsubstantiated interests that stick around because they don't hurt the evolutionary drive enough to weed themselves out.

        6 votes
    2. [4]
      petrichor
      Link Parent
      Very cool. I wonder what other evolutionary changes happened because of the rapid shift from hunter-gatherer life to farming and industry.

      Very cool. I wonder what other evolutionary changes happened because of the rapid shift from hunter-gatherer life to farming and industry.

      1 vote
      1. [3]
        lonjil
        Link Parent
        It's wasn't an evolutionary change. Our food is too soft, so there isn't enough force applied during our growing years for our mouths to get into the right shape.

        It's wasn't an evolutionary change. Our food is too soft, so there isn't enough force applied during our growing years for our mouths to get into the right shape.

        7 votes
        1. [2]
          petrichor
          Link Parent
          Ah, that makes much more sense.

          Ah, that makes much more sense.

          1. UniquelyGeneric
            Link Parent
            I am reminded of how domesticated foxes who were selectively bred for friendliness towards humans exhibited other traits like floppy ears and (notably) more brittle teeth. This only took a few...

            I am reminded of how domesticated foxes who were selectively bred for friendliness towards humans exhibited other traits like floppy ears and (notably) more brittle teeth. This only took a few generations to manifest as well, so evolution does not need to run its natural course for knock-on effects to take hold.

            Makes me wonder if there’s some truth to social Darwinism wherein by no longer selecting for primal survival skills and instead prioritizing cooperation within urban environments, humans have developed other emergent phenotypes.

            5 votes
  2. [5]
    Amarok
    Link
    Put another way - our ancestors who didn't have good jaws and more perfect teeth didn't live long enough to become fossils. Tooth infections can kill, and the pain of bad teeth certainly doesn't...

    Put another way - our ancestors who didn't have good jaws and more perfect teeth didn't live long enough to become fossils. Tooth infections can kill, and the pain of bad teeth certainly doesn't help one eat to survive. While I agree that the evolutionary pressures have changed, couldn't there be a bias in the sample sets of old fossils because of this? Did ancient children have perfect teeth as well?

    2 votes
    1. [4]
      Rez
      Link Parent
      Why would poor teeth prevent fossilization?

      Why would poor teeth prevent fossilization?

      2 votes
      1. [2]
        UniquelyGeneric
        Link Parent
        Probably less to do with fossilization itself and moreso the sheer prevalence of straight-toothed humans who live longer lives and have more opportunities to procreate and continue passing “good”...

        Probably less to do with fossilization itself and moreso the sheer prevalence of straight-toothed humans who live longer lives and have more opportunities to procreate and continue passing “good” dental genes

        2 votes
        1. Rez
          Link Parent
          Right, that just means most humans had good teeth so it's unsurprising that most fossils would have good teeth. We all die so we all have the potential to end up as fossils; I don't see why good...

          Right, that just means most humans had good teeth so it's unsurprising that most fossils would have good teeth. We all die so we all have the potential to end up as fossils; I don't see why good or bad teeth would impact our chances of being fossilized. If you die of a tooth infection you can end up a fossil all the same. We have plenty of fossils that show evidence of disease and injury, even bone fractures severe enough where we can infer the person must've been nursed or supported back to recovery. The lack of bad teeth in comparison to all the other bad things we can see implies that our bad teeth is likely a disease of civilization, the same way myopia has been skyrocketing over the last century. On that note, if you want to prevent or mitigate myopia in your children, it appears to be the case that sunlight exposure in childhood years is critical. Close range vision work does not seem to be the cause (though it can cause eye strain and discomfort) - the common root between bookish kids and gamers having bad eyesight may be all the time spent indoors.

          6 votes
      2. Amarok
        Link Parent
        My thought was that there's just more adult to fossilize than child, since the children with dental problems wouldn't make it to adulthood.

        My thought was that there's just more adult to fossilize than child, since the children with dental problems wouldn't make it to adulthood.

        2 votes
  3. cmccabe
    Link
    I think this (generally) is a pretty important topic for modern medicine. How many of our species' other challenges are caused by a mismatch of evolved human psychology/physiology to the modern...

    I think this (generally) is a pretty important topic for modern medicine. How many of our species' other challenges are caused by a mismatch of evolved human psychology/physiology to the modern environment? ADHD? Back pain? Allergies? And what solutions can we find by investigating the differences between our modern built environments, our diets, our hygiene practices, etc. and those of our hunter gatherer ancestors?

    Wikipedia has a pretty decent entry on the topic of "Evolutionary Mismatch", for anyone interested: https://en.wikipedia.org/wiki/Evolutionary_mismatch

    2 votes