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Earth Science Technology

How Sliced Meat May Have Driven Human Evolution (sciencemag.org) 132

sciencehabit writes: The most tedious part of a chimpanzee's life is chewing. Our primate cousins spend six hours a day gnashing fruits and the occasional monkey carcass — all made possible by the same type of big teeth and large jaws our early ancestors had. So why are our own teeth and jaws so much smaller? A new study credits the advent of simple stone tools to slice meat and pound root vegetables, which could have dramatically reduced the time and force needed to chew, thus allowing our more immediate ancestors to evolve the physical features required for speech. The abstract for the (paywalled) article is more informative than many.
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How Sliced Meat May Have Driven Human Evolution

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  • along with Pilot Bread (hard tack)
  • by Empiric ( 675968 )
    All such "explanations" backed primarily by feelings of vague plausibility should be required to show how they are better supported than ones such as BAHfest [bdcwire.com].

    Maybe early proto-Republican campfire debates caused the evolution of "large hands" as selective advantage for tribal power struggles. Probably not. Show me specifically how their conjecture is scientifically stronger.
    • by Tablizer ( 95088 )

      proto-Republican

      That's redundant ;-)

    • That was a perfectly cromulent analysis.
      Except for the sys.

  • Tooth longevity (Score:5, Interesting)

    by Anonymous Coward on Wednesday March 09, 2016 @04:26PM (#51667913)

    Surprised they didn't mention that a longer lasting tooth would have been a huge advantage as well:

    "Slicing, whether with a knife or a sharp stone flake, changes all that. Suddenly, hominins could cut up the elastic muscles of a carcass into smaller bits before putting them in their mouths, making them chewable and easier to digest. Pounding has a similar effect on tough, fibrous root vegetables. “What we found is that by simply slicing meat and pounding vegetables, a hominin would be able to reduce the number of chews they use by about 17%,” Zink says. “That equates to 2-and-a-half million fewer chews per year.”

    Imagine a 17% less worn tooth. Tooth loss is a huge disadvantage in the wild, just look at how desperate large predators get when they cannot hunt effectively.

    An individual living 17% longer would be able to learn and pass on their knowledge and build a more effective society, perhaps even helping invent fire along the way.

    • It's easy to argue exactly the opposite. Tools and fire have let us get away with having crappy teeth resulting in devolution- look how ugly and crooked human teeth (without orthodontics) are compared to the rest of the animal kingdom. You never see bad teeth in a chimp, wolf or lion.
      • by TWX ( 665546 )
        I donno, allowing a person with otherwise-awful teeth to survive seems like a good personal survival tactic. Granted, it may not be that good for the species, but remember, at one time the British ruled much of the planet even with their bad teeth.
        • And they have- which allows them to reproduce and pass on their crappy teeth to their children. Not sure why evolution/devolution is so hard to understand.
          • by TWX ( 665546 )
            Yep. A negative trait has to impact reproduction rates fairly significantly for it to matter.
        • by Muros ( 1167213 )

          And today, the world power is the USA, with worse teeth [washingtonpost.com] than the British.

      • Re:Tooth longevity (Score:5, Insightful)

        by Opportunist ( 166417 ) on Wednesday March 09, 2016 @07:19PM (#51668961)

        Wolves and lions with bad teeth simply die.

        Also, these animals are a rather poor example of why living longer than one generation needs to procreate has a benefit. They do not tend to live in multi-generation packs. We do. Even today having parents to rely on when you have offspring is a huge advantage compared to those who cannot drop their young on their own parents to go out and earn a living. Consider how much higher the chances for your pack were when you went out hunting while your young were protected by your own parents who not only provide protection but can also aid you with their experience in rearing offspring.

        IIRC the life expectancy of an early human who survived the first 5 years of his life was in the area of 35 years. 17% only means about 5-7 extra years, but it can make a huge difference for the chance of your kids' survival if your parents are around an extra 5-7 years. Considering that a woman can bear children about roughly once a year, this can mean an extra 5 offspring surviving.

        • "Wolves and lions with bad teeth simply die."

          After getting desperate enough to go after humans, who are normally untouchable because whilst they may be easy to hunt individually, the predators learned long ago that this is a prey animal which forms groups and hunts back.

          This is what the OP was referring to about them getting desperate.

      • by AC-x ( 735297 )

        look how ugly and crooked human teeth (without orthodontics) are compared to the rest of the animal kingdom.

        Actually pre-agricultural peoples had very good teeth [washingtonsblog.com], our recent change in diet has just happened to quickly for evolution to compensate.

        • When I talk about bad teeth I mean irregular/crooked etc. which is why I mention orthodontics. I am not talking about dental caries....
      • There is no such thing as devolution - that implies that there is a preferred direction for evolution, which has no basis in fact (other than increasing genetic complexity, which has little relevance to specific features).

        Is it devolution that our appendix has shrunk almost to nonexistence? No, that's simply evolution gradually removing something that's no longer particularly relevant to our survival. Similarly if our teeth fade away to nothing because we don't really need them anymore, that's also evolut

    • Cooking.. (Score:3, Interesting)

      by thesupraman ( 179040 )

      And the other small factor they missed.. Cooking!
      Cooking has a large known effect on consumption and abduction of food. Especially meat. Resulting in needing to eat less quantity and being easier to chew..

      No.. That couldn't be a factor.. Must have been those thin slices. Sigh.

      Chewing cooked food is much much easier.. Making a larger difference than sliced meat (you don't think stone tools produce nice thin slices do you?)

      Sounds a lot like someone flash of the moment idea that they rushed to publish rather t

      • Figured that out all by yourself, did you? TFA even talked about that.

        The thesis is that stone tools preceded evidence of cooking by some long period of time. So the tools were used to beat the food into submission. Barbecue came later.

        Might be where the term 'beating a dead horse' came from.

        • Figured that out all by yourself, did you? TFA even talked about that.

          The thesis is that stone tools preceded evidence of cooking by some long period of time. So the tools were used to beat the food into submission. Barbecue came later.

          Might be where the term 'beating a dead horse' came from.

          Actually no, I didnt 'figure that out all by myself', because, as you say, it is well known.
          As far as I can tell they dont provide any solid evidence that stone tools actually drove such changes. They seem to be just deciding that arbitrarily, then thrashing around looking for possible reasons for it.

          Cooking has very well documented and researched effects on physiology, perhaps you should do a little research. Their theory has much less behind it.

          Cooked your dead horse enough for you?

        • No, this is where slicing a dead horse came from.

          The part about beating stuff was about root vegetables.

          We didn't start beating dead horses until we acquired abstract language.

      • Re:Cooking.. (Score:4, Informative)

        by AthanasiusKircher ( 1333179 ) on Thursday March 10, 2016 @01:34AM (#51670233)

        And the other small factor they missed.. Cooking!

        They "missed" it, huh? Why is cooking discussed in detail in TFA and even mentioned twice in the abstract then?

        Cooking has a large known effect on consumption and abduction of food. Especially meat. Resulting in needing to eat less quantity and being easier to chew..

        Yes. No one disputes it. It's mentioned in the article. Problem is: best evidence now is that cooking only started in a controlled way a few hundred thousand years ago, maybe 500,000 at the most. Meanwhile, the changes actually mentioned in TFA began perhaps as early as 2 million years ago. Stone tools were around then (and had been used perhaps as much as 3 million years ago).

        No.. That couldn't be a factor.. Must have been those thin slices. Sigh.

        Uh, or TFA could explicitly acknowledge multiple times that cooking was a major evolutionary factor, but they're perhaps hypothesizing about a different earlier stage?

        Sounds a lot like someone flash of the moment idea that they rushed to publish rather than something with much backing

        Rather ironic to read this coming from someone who didn't even take the time to find out what the article was about before posting in ignorance. Is TFA conclusive evidence of anything? Absolutely not -- it's just throwing out a possible idea for a stage of evolution where jaw size and strength decreases, etc. before we have any solid evidence of cooking.

        What's your theory?? What's the backing for it?

      • Cooking plausibly drove the recent rapid shrinkage of our teeth, halving in size in the last 100,000 years. Not only does it make food easier to eat (vegetables as well as meat - modern vegetables bear little resemblance to the durability of wild plants), but it increases the accessible calorie content as well, breaking down fiber, etc. into forms that our digestive system can process, so that you don't need to eat as much. (something like a 15-20% calorie increase if I recall correctly)

        But we've only harne

  • Bacon, it's your evolutionary duty!
  • POSSUM

    Ef dey 's anyt'ing dat riles me
    An' jes' gits me out o' hitch,
    Twell I want to tek my coat off,
    So 's to r'ar an' t'ar an' pitch,
    Hit's to see some ign'ant white man
    'Mittin' dat owdacious sin—
    Wen he want to cook a possum
    Tekin' off de possum's skin.
    W'y dey ain't no use in talking',
    Hit jes' hu'ts me to de heart
    Fu' to see dem foolish people
    Th'owin' 'way de fines' pa't.
    W'y, dat skin is jes' ez tendah
    An' ez juicy ez kin be;
    I knows all erbout de critter—
    Hide an' haih—don't tal

  • Disagree (Score:3, Insightful)

    by Anonymous Coward on Wednesday March 09, 2016 @04:51PM (#51668053)

    Small teeth can just as easily eat a whole animal as big teeth. Teeth aren't just used for chewing but for attacking and taking down prey. It was tools that allowed humans to take down prey without the need for biting that allowed smaller mouths to be evolutionarily OK.

    And beyond that, COOKING the meat was far more advantageous than tools to slice it.

    "Sliced bread makes us evolutionarily superior"

    Yeesh.. this isn't science, this is drunken bar talk...

    • by pubwvj ( 1045960 )

      I wonder if you've ever actually hunted. Not with a rifle which is a remote action but by running your prey to the ground and killing it. I've done it to prey far larger than me. It's not all that hard. We are evolved for doing this. We work as packs, running our prey in a grand circle, always turning. Eventually the prey is exhausted. Humans and wolves are particularly good at this hunting tactic and were long before the use of firearms, bows, spears or even knives or stone kludges. The run down and kill i

  • Fire (Score:5, Insightful)

    by wisnoskij ( 1206448 ) on Wednesday March 09, 2016 @04:52PM (#51668061) Homepage

    Knives don't really replace chewing, fire does that.

    • Knives don't really replace chewing, fire does that.

      Well, knives do make it a little easier to get the mammoth over the fire.

    • by Anonymous Coward

      Absolutely. There's even been a book out for years on it:
      https://en.m.wikipedia.org/wiki/Catching_Fire:_How_Cooking_Made_Us_Human

      Cooking is essentially external digestion.

    • Jeez - read the linked abstract in TFS. It talks about cooking and fires. Problem is our first clear evidence of controlled fires for human ancestor use was somewhere around 250,000-300,000 years ago, maybe 500,000 at the most. On the other hand, TFA points out that Homo erectus was already showing smaller jaws, reduced bite force, and smaller gut over a million years earlier. So, how did this evolution happen unless Homo erectus was somehow able to extract more calories more efficiently? Well, the firs
      • Except, I see no way that a stone tool can be used instead of chewing, unless they want us to believe that they used a mortar and pestle and made a meat paste.

        Far more likely, and this is a use that is provably plausible, they used the stone tools so that they no longer had to bite animals to death, meaning that far less biting strength was needed. And with the increased hunting success, which tools gave them, they no longer needed to wring every last calorie out of food. It was more effective to be lean an

        • I agree that relieving our teeth of hunting duty was probably the bigger contributor. But stone tools also contribute closer to digestion as well. Cutting through the hide certainly, and cutting off more manageable size chunks of meat - I imagine tearing a raw chunk of meat off an animal takes a fair bit more peak jaw strength than chewing it. And while does seem unlikely that the stone tools of the age were sharp enough to encourage the slicing of lunchmeats, even thick steaks cut across the grain would

  • As in, it wasn't accepted scientific theory that a combination of fire and stone knives are responsible for our decreased gastrological abilities?

    It seemed patently obvious to me and should have been accepted fact 50 years ago, if not 100 years ago.

    Humans can not live without knives and fire. We can't kill large animals or microscopic parasites because our biological tools for consuming unprepared foods are practically non-existent. But we evolved from animals that a) did not have fire or knives and b)

    • We can't kill large animals or microscopic parasites because our biological tools for consuming unprepared foods are practically non-existent.
      That is complete nonsense.

      Hint: Sushi, Salad, Tartar.

      Or: Inuit, or other indigenous tribes that still eat stuff raw or merely fermented. Ever seen Japanese people falling over fresh delivered whale meat? They eat stuff raw, I would womit on, like the blubber. But so do Norwegians, can't be a "trait".

      Perhaps you don't know what tartar is .. but keep in mind even T-Bone

      • T-bones/porterhouses are such large steaks they are usually cut too thin. Hence overcooked (not raw in the middle).

        • That comes down entirely to cooking technique. Throw a thin steak sucker over a hot fire just long enough to sear the juices in and caramelize the surface and it can still be cold inside.

          The reason most modern meat is served over-cooked is, I would suggest, twofold:

          1) Modern meat is hideously diseased due to industrial farming practices - milk from your typical dairy cow for instance has something like 100x the bacterial load as from a free-range cow, despite heavy antibiotic use. Plus the meat's been dead

          • Minimum cook time on a side is the time it takes for the meat to seer and release from a screaming hot grill/grill pan.

            The way most T-bones are cut, the release flip leaves you at about medium.

            You're just wrong about most beef. Ground beef needs to be cooked. But any solid chunks of beef are fine to eat raw. As long as it's fresh and you seer the surface.

            I do make a point of buying the slaughter house vacuum packs. But that's because of the minimum wage scumbags that work at the local groceries.

            • >But any solid chunks of beef are fine to eat raw. As long as it's fresh and you seer the surface.

              As long as it doesn't contain mad cow disease, or any other infectious agents capable of jumping the species barrier. Cow is fairly distantly related to us, so there aren't too many. Not nearly as bad as raw pig, but not nearly as safe as raw fish (and you can still get a lethal case of liver-flukes from fish).

      • by aXis100 ( 690904 )

        Eating food raw requires you to eat it very fresh, or have refrigerated storage. Since cavemen didn't have fridges, that leaves the fresh option.

        Eating things fresh implies that you have space to eat it, and only gather a small amount at a time, That's not a very reliable survival option and leaves you a high risk of starving if a few hunts are unsuccessful.

        Fire and knives allow for larger kills to be made, and older meat to be consumed safely. It even allows for preservation of meat through drying and

        • by jafiwam ( 310805 )

          It even allows for preservation of meat through drying and smoking etc. This is a great survival technique to help survive periods where fresh food is unavailable.

          That latter part also puts tremendous selective pressure that benefits smarter people that can think ahead and get around the "instant gratification" trap.

        • Not really. Plenty of animals will hide their kill to continue eating it over the course of many days. It gets to tasting funny after a while, but most of the stuff that thrives in dead meat isn't actually terribly dangerous to the living. And most of the stuff that is dangerous to the living was already present in the live animal, so you're getting it regardless of how fresh the kill. Also, being hungry and not having any concept of the microbial theory of disease would drastically reduce your hesitanc

        • Eating food raw requires you to eat it very fresh, or have refrigerated storage.
          Like cheese, beer, suaerkraut and thousands of fermented meals the planet is offering?
          Ever looked how Eskimos/Inuit store/prepare food for the next year? Or how Dogs, Lynx, Wolves do it for the next week? Or even month? Or squirrels? Or Ravens?

          Well, be happy with your fridge. You likely die if you have none.

      • 1) If you think sushi, salad and tartar are created without knives, you are an idiot. Worse, sushi consists of rice, which needs at the very least fire to boil the water. Tartar is made with a massive amount of knife work. Salad is the closest, and we can't live on raw vegetables alone, except in very rare circumstances where certain plants all grow in the same area.

        2) The Inuit and Japanese all use knives. The fact you don't think they do indicates either extreme ignorance, or racism. Hell, most o

        • If you think we where talking about knives, you are an idiot.
          We were talking about food that is eaten raw. The parent claimed we cant do that .... no idea if you were that parent.
          If you want to nitpick on rice in suhi, then substitute sushi for sashimi, in case you even know what that is.

  • To eat tough meat, chewing is almost futile. Grab one part in your hands, the other in your teeth, and tear it. That's what the canines are for, that's what wild predators like wolves and big cats do. The premise of the article is flawed by not considering all possibilities.
    • Only problem is we don't have canines worth speaking of, and had largely lost them even before we had stone tools.

      Also, canines are typically considered to have their primary usage a little earlier in the process - in order to keep a grip on your prey while it's still struggling to get away, as well as making it easier to inflict internal damage likely to actually kill it. Catching lunch the first time is hard enough, you don't want to have to catch it again for the second attack.

      And then there's the fact t

  • I don't spend this much time on many things like this but for some reason this came across as bad science.

    A session with Google and no knowledge anthropology I found this:

    Chimpanzee's habit was an entire Continent away from H. erectus
    http://www.janegoodall.ca/abou... [janegoodall.ca]
    (not that big of a deal we do have Hurricanes, Cyclones and Typhoons to mix the groups)

    Chimpanzee's are a different time line than humans
    https://en.wikipedia.org/wiki/... [wikipedia.org]

    So what do the modern apes—and in particular our closest relatives the chimpanzees and bonobos—eat? Plants. Yes, plants. ... But most chimps don’t eat such meaty treats often. Three percent of the average chimp diet comes from meat. On average, nine days a year are meat days for chimps.
    http://blogs.scientificamerica... [scientificamerican.com]

    Despite their hunting behavior, however, only a very tiny percentage–perhaps as small as two percent–of a wild chimp’s diet consists of meat or insects.
    http://www.allaboutwildlife.co... [allaboutwildlife.com]

    Google this phrase: what do you feed a chimpanzee - give one this blurb:
    It also eats leaves and leaf buds. Seeds, blossoms, stems, pith, bark and resin, insects, and meat make up the rest of its diet. While the common chimpanzee is mostly herbivorous, it does eat honey, soil, insects, birds and their eggs, and small to medium-sized mammals, including other primates.

    http://www.janegoodall.org/ [janegoodall.org] is a worthless site unless you wish to give money.

    Topic: H. erectus meat consumption is associated with __________.
    Not one answer includes teeth
    http://science-forums.com/inde... [science-forums.com]

    The only thing that associates chimpanzee (meat eating) and evolve of humans jaws to is the submitted article itself.

    • by AC-x ( 735297 )

      Talking about "bad science"

      Chimpanzee's habit was an entire Continent away from H. erectus

      Huh? Homo Erectus finds very much overlap with even the modern Chimpanzee ranges in Africa you linked to, and it's not hard to imagine that Chimpanzees' range extended much further 2 million years ago than it does today.

      Chimpanzee's are a different time line than humans

      They covered that already - they're talking about our ancestors, who had chimp-like jaws: "all made possible by the same type of big teeth and large jaws our early ancestors had."

      So what do the modern apes—and in particular our closest relatives the chimpanzees and bonobos—eat? Plants.

      Again, already covered - "A new study credits the advent of simple stone tools to slic

  • So, sliced bread is the greatest thing since sliced bread, eh?

  • How old are the tools? Oldest things recognizable as human made tools are some 2.8 million years old. Tool use must be older than that but the tools they used were indistinguishable from ordinary natural rock. May be there were wooden tools too which did not survive.

    All the hominids with robust skulls and jaws are that old. Tool use did not change the anatomy of hominids when they were invented.

    Fire was tamed some 500K years ago. There was a gradual change, even Homo sapien neanderthalis had less robust

    • Firstly, 500kya for fire mastery is being generous. Solid evidence starts around 125kya, though 400kya has wide scholarly acceptance. But yes, even 125kya lines up nicely with the rapid tooth shrinkage that has been occurring for the last 100ky.

      But, our jaws started shrinking long before that. 2.8Mya Homo habilis had a chimpanzee-like jaw with oversized molars. A million years later Homo erectus had much smaller human-like molars. And there's no fire mastery that far back, so what allowed for that shri

  • bacon, is there anything it can't do?
  • ...and be human-smart? If I (still) had monkey teeth, would I still need a bottle opener?

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