字幕表 動画を再生する 英語字幕をプリント Toes are just so weird, I mean have you ever looked at them, they’re so stubby and useless, why can’t we have cool grippy toes like chimpanzees? Hey guys Julia here for Dnews. This little piggie went to market and this little piggie is...well, it makes no sense. It looks like nothing else in the animal kingdom. Seriously. have you ever just looked at your toes and thought why? Well, Hallo Pjotter asked us how our toes evolved. And that’s a good question. Toes likely evolved from the same bones that became fins, wings, or hooves in other species. The dominating scientific theories are that fingers and toes are exclusive features of tetrapods, or vertebrates with limbs. But according to one study, toes may have evolved even before fish left the ocean. The study, published in the journal Nature, found 385 million years ago, a fish named Panderichthys, had homologous bones to our fingers and toes. Either way, phalanges are over hundreds of millions of years old. Human toes, specifically, are a little newer to the scene. Of all the other living primates, we’re the only ones that exclusively walk upright on two legs. Other primates, like chimps, have little grippy feet and ours are just kind of weird looking in comparison, but research shows they used to be grippy back in the day. According to a study published in the journal Foot and Ankle International, our ancestors Australopithecus afarensis, which lived 3.5 million ago years ago, had feet that looked remarkably like a chimpanzee’s! Fast-forward to homo habilis an ancestor who lived 1.76 million years ago. And her feet looked a lot like ours do now. We traded in our opposable toe for shorter toes overall, and gained an arch in our foot. What happened in that interim? Well in short, our ancestors came down from the trees and started walking on land. As our foot evolved to support walking on the ground, we started moving faster and faster, eventually learning to run. These changes forced our feet to evolve to deal with both balance and propulsion in a highly efficient way. Basically, our feet became more springy and shock-absorbent. And there's a study to back this up in the Journal of Experimental Biology, showing basically, these toes are made for running. The researchers created models which showed that longer-toed individuals do more mechanical work to stabilize their joints and ligaments. This means they use more energy to run the same distance as shorter-toed people. This supports what’s called the “endurance running hypothesis” or the idea that our ancestors were really good at running long distances in order to chase down and wear out prey. In this kind of hunting style, those with long toes are evolutionarily selected against because it takes them more work to do run down the same prey. The researchers also found shorter toes might reduce the risk of injury meaning, long-toed people would expend more energy to run the same distance, AND run a higher risk of injury while doing it! So, our toes, while short and stubby, maybe have evolved to help us run, keep our balance, and absorb impact. So, the next time you go for a jog thank your toes, even though they can’t help you climb trees anymore. The weird thing though I keep hearing about toes, is that our pinky toe is going away, that we’re evolving out of it. It’s just a useless vestigial structure. But that’s more old wives tale than anything else. As for one of our other useless lumps left over from evolution: the appendix, it might not be so useless after all, Tara has the whole story, right here.
B1 中級 足の指はなぜこんなに変な形に進化したのか?#進化した足の指はなぜこんなに変に見えるのか? (Why Did Our Toes Evolve To Look So Weird? #AskDNews) 68 7 陳叔華 に公開 2021 年 01 月 14 日 シェア シェア 保存 報告 動画の中の単語