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为什么我的牙齿不整齐

Why Do We Have Such Crooked Teeth?

你可能因为一堆原因需要去看牙医
You might need to go to the dentist for
从补牙齿到
a bunch of reasons, from filling cavities
好的牙齿需要矫正的 我们许多人
to wisdom tooth surgery. A lot of us have
因为牙齿挤在一起或歪扭 就需要或想要
overcrowded or crooked teeth and need or
用牙套把它们矫正过来 但是
want braces to straighten them out. But
你没有看到其他物种而且心想 哦
you don’t see other species and think, “Oh
天呐 那只海狸的牙齿肯定可以
man, that beaver’s teeth sure could be
被矫正过来的
straighter.”
所以为什么我们如此容易笑歪呢?
So why are we so prone to crooked smiles?
好了 我们言归正传 在我们现代人的口腔中
Well it turns out there’s just not
没有足够的空间
enough space in our modern human jaw
让我们所有的牙齿轻松的容纳在里面
for all of our teeth to fit in easily.
但情况并非一直如此 事实上
But it wasn’t always this way. In fact, the
这个问题可能和大约一万年前的农业的出现
problem might be linked to the rise of
有关系
agriculture around 10,000 years ago.
当人类开始种植蔬菜和饲养牲畜时
Growing vegetables and raising animals
人类对食物的加工
went hand-in-hand with a big increase
也大幅增加了
in how much humans processed their food,
比如把食物切成小块
like by cutting it into smaller pieces or
或者烹饪 这使得食物更容易的下咽
cooking it. This made food much easier to
而且我们不需要费很大劲的去咀嚼
eat so we didn’t need as much chewing
根据人类学的证据
and biting power. According to some
这就意味着
anthropological evidence, this also meant
我们的下巴收缩了
that our jaws shrank, but the number of
但我们牙齿的数量保持不变
teeth we had stayed the same, leading
导致了我们今天牙齿畸形的悲哀
to the orthodontic woes of today. One study
一个关于颅骨的研究发现
look at skulls from before, during, and
中东地区在农耕时代之前、过渡到农耕时代及之后
after the transitions to agriculture in
人类的下颔是一直是变化的
the Middle East and found changes in the
前农耕时期的下颔骨
jaws. Jaw bones from pre-agricultural
显示出牙齿因为剧烈的咀嚼而导致的磨损
times showed a lot of wear and tear on
但是牙齿并不拥挤
the teeth from intense chewing, but very
但在农耕之后
little crowding. After farming though, jaws
下颔比以前变得更宽 更短
became wider and shorter front to back,
而且他们有更多的拥挤而歪扭的牙齿
and they had more crowded, crooked teeth.
另一个研究
Another study compared the skull and jaw
把来自全世界的11个现代人类种群的头盖骨和下颔进行了对比
shapes of 11 modern human populations
其中包括
from around the world, including some
一些农民和一些依靠狩猎采集为生的人
farmers and some hunter-gatherers, and
后者有着比农民更长 更拥挤的下巴
hunter-gatherers had longer, narrower
特别是下巴变得更浅
jaws, especially lower jaws, than the
这个当然也更有利于更高强度的咀嚼
farmers, which are better for intense
我们下巴形状的这些改变
chewing. These changes in our jaw shape
虽然可能不是因为我们基因的改变
might not be because of changes in our
在工作中 具有更短的下巴的农民可能更容易生存
genes though. It’s not necessarily natural selection
这并不是自然选择的结果
at work, where the farmers with shorter jaws
相反
were more likely to survive. Instead, this
这可能是进化生物学家所谓的
might be an example of what evolutionary
发育可塑性的一个典例
biologist called developmental
生物体向不同方式生长发育的可能性
plasticity, an organism’s potential to
取决于它所处的不同环境
grow in different ways, depending on its
一个关于啮齿型动物的研究
environment. A study on small rodents
例如蹄兔
called hyraxes for example found that
发现那些用烹煮过的较软的食物饲养的蹄兔
animals raised on softer cooked food
相比于那些以生的或干的食物为食的蹄兔
instead of raw or dried food had less
前者的下巴和脸的下部骨头发育程度较低
growth in the bones of their jaws and
然而却很难直接对人类进行测试
lower faces. It’s hard to test this
因为那意味着
directly in human though because that
人们一生当中大部分时间
would mean limiting what people could
吃什么都得受限 但是
eat for a huge chunk of their lives but
很有可能发生的是 如果我们每个人
it’s possible that each of us could
在我们的发育期间只吃硬的食物
develop a bigger stronger jaw if we only ate
那我们就会有一个更大更强壮的下巴
tough foods while growing up. So our love of
所以我们对熟食饭菜的热爱
warm cooked meals from tender meats to
从柔软的肉到奶酪马克罗尼意面
mac and cheese might have doomed
就注定我们可能需要戴牙套生活好几年
some of us to years of braces but in
但是长期来讲 是愿意说话时露出一点牙齿呢
the long run if we’re talking like a few
还是像永远在咀嚼食物
overcrowded teeth or like chewing your
直到你的牙齿坏掉呢?
food forever until your teeth break, I will
我会选第一个特别是
take the first one especially if it’s
可以吃奶酪马克罗尼意面的话
got mac and cheese
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视频概述

讲述人类的牙齿进化过程,与职业和食物息息相关。为何现代人类牙齿不整齐?

听录译者

收集自网络

翻译译者

李奶奶保护协会

审核员

Ah~Qiu

视频来源

https://www.youtube.com/watch?v=FWds-tGnHlI

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