你体内的鱼（2014）

Yeah. Look at that.
而那将我们带到一个我最喜欢的主题…
And that takes us to one of my favourite topics...
…牙齿
..teeth.
对解剖学家来说，牙齿可以揭露这只动物的一生
For anatomists, teeth can reveal a lot about an animal's life.
其中一位历史上最伟大的解剖学家是…乔治.居维叶
One of the great anatomists of all time was Baron Georges Cuvier,
他生活在19世纪初的巴黎
who lived in Paris in the 1800s.
他是极端的重要、极端的聪明…
He was remarkably important,remarkably smart
和极端的自大
and remarkably arrogant.
他曾经吹嘘，而他是这样吹的…
He had a boast,and his boast was, show me
"给我看任何动物的牙齿，然后我就可以重建出整副骨骼"
the tooth of any animal and I can reconstruct its entire skeleton.
结果证明居维叶几乎没说错…这里是牙齿
Turns out Cuvier was pretty much right. Now here's a tooth.
这是颗很大的牙齿，明显的是来自于很大的动物
This is a huge tooth.Clearly came from a big animal.
顶端是平面，这只动物很明显的咀嚼植物
Flat surface on top.That animal clearly chews plant material.
咀嚼植物的大块头动物是谁？…大象
What is a big animal that eats plants? An elephant.
这里是另一副…大颗的犬齿，后排则是像利刃一般的牙齿
Here's another one.Large canines,big scissor-like teeth in the back.
这只生物很明显的…是为了吃肉而存在
This creature clearly,you know,is built to eat meat.
这是狮子
This is a lion.
所以牙齿包含了…许多基本生物特征的解答
So teeth contain so many answers to the basic biology of creatures.
它们可以告诉我们，这只动物吃什么，它们可能的模样…
They can tell us what animals eat,what they likely looked like.
但它们能做到的远不只这样
But they can do so much more.
它们可以解开…居维叶做梦也想不到的谜题
They can answer mysteries that Cuvier could only have dreamed of knowing
牙齿提供了一个窗口，让我们可以看到遥远的过去，
Teeth give us a window into out distant past by telling us
我们的祖先是如何生存和进化的
how our ancestors lived and evolved.
罗杰…想要让我看看，
Roger wants to show me
一具相当惊人的，已有两亿五千岁的化石标本
a particularly striking specimen that's over 250 million years old.
噢，哇！看看这个！
Oh, wow, look at that!
好凶猛，看看那些牙齿
Ferocious. Look at those teeth.
这是丽齿兽，它们是那个时期的食肉动物
Now, this is a Gorgonopsid. These are the carnivores of that time.
天啊，我想这些牙齿说的很清楚了
Boy, the teeth really tell a story on that one.
确实是，没错
They certainly do, yeah.
丽齿兽…也许看来有点像霸王龙
Gorgonopsids might look a bit like T-rex,
但是它们比任何恐龙出现前，还要再早几百万年
but they lived millions of years before any dinosaur was around.
当你看到这具化石，
This is a fossil that when you see it
你完全能了解它如何生活，它的行为…
you know exactly how it lived,what it did, you know.
-这家伙可不会和你闹着玩
-绝对不会，没错
This wasn't messing around,this creature. Absolutely, yeah.
丽齿兽是凶猛的掠食者
Gorgonopsids were ferocious predators,
拥有一整口高度特化的牙齿
with mouths full of highly specialised teeth.
而那描绘出了戏剧性的转变…
And that represents a dramatic change
在大多数爬行类动物的牙齿上
from the much more basic teeth of reptiles.
多数的爬行类，都有着一口非常相似的锋利锥形牙齿
Most reptiles have sharp peg-shaped teeth that all look really similar.
这些牙齿…只适合用来做一件事…
These teeth are only great for one thing
咬！
biting.
它们无法有效的咀嚼食物，
They can't strip of chew their food.
于是它们将食物撕扯成大块，
Instead they tear off chunks....
…然后将它们整块吞下
...and then swallow them whole.
丽齿兽的牙齿，和它们的爬行类表亲，
The Gorgonopsids' teeth had come a long way
已经有很大的不同
from their reptilian cousins.
和之前的爬行类做比较，
Compared to the reptiles before it,
在犬齿和门牙上并没有什么不同，
there was no differentiation of incisors and canines,
但是这些变长的犬齿，是很显著的哺乳类特征
but this elongation of the canine is a particularly mammal-like feature,
而前排的牙齿，就像很多针尖组合在一起，
and the front teeth were like little needles that came together,
非常，非常适合用来撕肉
very,very well adapted for flesh tearing.
所你你在这里…开始见到牙齿排列上的差别
So here you start to see differentiation along the tooth row.
它们可以说是保有同样的形状，但是尺寸改变了
They're all sort of the same shape but they're different sizes,
因应不同需求而特化
specialised in different ways.
后犬齿
门牙
犬齿
丽齿兽…拥有像是瑞士刀一般的牙齿
Gorgonopsids had virtual Swiss Army knives for teeth.
巨大的犬齿…用来咬穿坚韧的外皮
Giant canines for piercing tough skin
而门牙则用来将肉从尸体上剥下
and incisors for stripping flesh off a carcass
所以它们不需要连骨头一起吞下，
so they could avoid swallowing whole bones.
一种前所未见的残暴高效食肉机，
Never before had such menacingly efficient eating machines
支配了陆地
ruled the land.
这些特别的丽齿兽…有着明显的长腿
These particular Gorgonopsians were fairly long legged
它们的前腿…轻微的弯曲，
and the front legs were slightly sprawled.
而后腿则是相对直立的
The back legs were nice and upright.
所以，甚至在它们的步态中，
它们也是半爬行类、半哺乳类
So, even in their gait, they're somewhat between a reptile and a mammal.
经过几百万年后，后排牙齿也开始逐渐特化
Over millions of years, back teeth would also become more specialised.
它们发展出特殊的脊状构造称作牙尖…来咀嚼食物，
They developed extra ridges called cusps for chewing food.
牙尖
使消化变的更有效率
Allowing more efficient digestion
并拥有更多力气去追捕猎物
and more energy for chasing prey.
这些远古的革新，就是臼齿的先驱…
These ancient innovations were the precursors to the molars
…今天在我们每个人的嘴里
we have in our mouths today.
如果没有臼齿…没辨法吃苹果，
Without a mouth of molars,couldn't eat the apple.
没有门牙，就没辨法吃…这是什么玩意？
A mouth of incisors, they couldn't eat the...whatever you call this.
-其实味道很不错
-番石榴卷
It's good by the way.Guava roll. Guava roll.
谢谢你…臼齿，因为我很高兴可以嚼这玩意
Thank you for having molars because I'm glad I can chew this one.
但你知道吗？这不起眼的牙齿对我们的生活相当重要…
You know, but the humble tooth is very important for our lives today.
你知道，当你咬下一口苹果，那是…
Every time you bite into an apple,all right, that is
一个相当复杂的行为
a very complex behaviour.
我们的前排牙齿…门牙，咬进苹果里，
Our front of our teeth,the incisors, bite into that apple.
而它们以近乎完美的方式进行
And they do so in almost a perfect way.
牙齿的咬合是以非常固定的模式，非常精准的模式…
The teeth occlude in a very fixed pattern, in a very precise pattern.
我们会把牙齿的精准咬合…认为是理所当然的，
We take for granted how we rely on precise tooth-to-tooth occlusion.
除非当事情出错！
Except when things go wrong.
除非我们撞掉了牙齿…或是类似的事
Except when we crack a tooth or something like that.
让我好好看看你，尼尔，
I'll have a good look at you, Neil,
并确定所有该在的东西都还在，
and make sure everything is where it's supposed to be,
也确定没有任何不该在那里的东西
and there's nothing in here that isn't supposed to be.
美妙复杂的牙齿，也许给了我们很好的咬合能力
Wonderfully complex teeth might allow us to have a great bite,
但这是有代价的，
but it's come at a price.
你知道，有件事你想想会很有趣，
You know, one thing that's interesting to think about is,
从爬行类转变到哺乳类所带来的后果…
you know, the consequences of the reptile-mammal transition
就是事实上我们需要牙医
are the fact that we need dentists!THEY LAUGH
-这是事实 -没错，太棒了！
-感谢你！
It's really true. Thank you.Right, excellent!
-太感谢了…非常感谢！
-感谢那些南非的化石
Thank you, South African fossils.Thank you very much!
爬行类不需要牙医，因为它们会制♥造♥大量的牙齿…
Reptiles don't need dentists cos they're producing lots of teeth
在它们的一生之中
throughout their lives.
碰-碰-碰，它们的牙就长出来在那里了
Boom-boom-boom, they produce them and they're out of there.
多数的爬行类，像是蛇，
Most reptiles, like the snake,
在它们的一生中会长出好几套牙齿
grow multiple sets of teeth in their lifetime.
在他们的口中，新牙齿不断的持续在形成
There's a constant stream of new teeth erupting in their mouths.
但当我们的乳牙脱落之后，
But after we lose our baby teeth,
我们接下来长出的恒齿，得要用上一辈子
we're left with one adult set to last us the rest of our lives.
这也许看来不是高明的战术，但是这也有好处
This may not seem like the best of strategies, but there is a plus side.
这让我们可以发展出非常精准的咬合
It allows us to develop our very precise bite.
如果你持续不断的替换你的牙齿，
If you're continually replacing your teeth, right,
我想就很难达到这样的成果
I think it would be hard to get that, you know,
这种极度精确的咬合…所以这对我们非常重要
micron scale occlusion,which is so really important to us.
你说的没错，当我们失去一颗牙齿，所产生的变化，
You're right, when we lose a tooth,the changes that occur
为了补偿那颗失去的牙齿，和多出的空间，
to compensate for the loss of that tooth, and the space that it held,
对我们的咬合有极深的影响
has a profound effect on our occlusions.
我们的牙齿排列之所以如此精准…是因为我们的祖先…
The reason our rows of teeth match up so precisely is that our ancestors
减少了它们的新牙制♥造♥数量
reduced the number of sets that they produced.
我们实现它，靠的是以更长的牙根和表层珐琅质，
We've made up for that by strengthening our teeth
让我们的牙齿更加坚固，让它们可以终生使用
with extra roots and thick enamel,to help them last a lifetime -
还有一些来自我牙医的小帮助！
along with a little help from our dentists!
这很有趣，下一次我会更仔细观察，
That's neat. I'll have to take a better look
当我带孩子们去动物园的时候
when I go to the zoo with my kids!
爬行动物区不是我最喜欢的地方，老实说…
The reptile house is not my favourite place, to be honest.
我比较喜欢它们是你找到的那种型态
I would like them in the form you find them.
-死掉的？
-对，死了两亿年！
Dead? Yeah, dead 200 million years!
对我的牙医师来说，
For my dentist,
罗杰在卡鲁的故事，简直是一场恐布的恶梦
Roger's tales from the Karoo would be the stuff of nightmares.
但对罗杰来说，这里发生的事，让人无止尽的心醉神往
But for Roger, what happened here is an endlessly fascinating drama.
对他而言，岩石和化石诉说着一个已经消失世界的故事，
To him, the rocks and fossils tell the story of a vanished world.
这些石头是由…密西西比州大小的蜿蜒河流沉积下来，
These rocks were laid down by large Mississippi-sized meandering rivers
它们泛滥的时间几乎长达一整年