TEDxVancouver
Jack Horner: Where are the baby dinosaurs?
傑克‧霍納：變形的恐龍
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小恐龍在哪裡？古生物學家傑克‧霍納在TEDx溫哥華發表引人入勝的談話，說明切開恐龍化石──包括幾種廣受喜愛的恐龍──頭骨，可以揭開驚人的秘密
Jack Horner - Dinosaur digger
Jack Horner and his dig teams have discovered the first evidence of parental care in dinosaurs, extensive nesting grounds, evidence of dinosaur herds, and the world’s first dinosaur embryos. He's now exploring how to build a dinosaur. Full bio
Jack Horner and his dig teams have discovered the first evidence of parental care in dinosaurs, extensive nesting grounds, evidence of dinosaur herds, and the world’s first dinosaur embryos. He's now exploring how to build a dinosaur. Full bio
Double-click the English transcript below to play the video.
00:15
Shall I ask for a show of hands
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可以請各位舉手
00:18
or a clapping
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或是鼓掌
00:20
of people in different generations?
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讓我知道各位的年齡嗎？
00:23
I'm interested in how many
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我想知道在座有多少人
00:25
are three to 12 years old.
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年齡在3到12歲？
00:27
(Laughter)
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(笑聲)
00:31
None, huh?
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一個也沒有 嗯？
00:34
All right.
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好吧
00:36
I'm going to talk about dinosaurs.
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今天我的主題是恐龍
00:38
Do you remember dinosaurs when you were that age?
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各位還記得恐龍嗎？ 你們3到12歲時很愛的？
00:41
(Applause)
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(掌聲)
00:48
Dinosaurs are kind of funny, you know.
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話說恐龍還蠻搞笑的
00:51
(Laughter)
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(笑聲)
00:53
We're going to kind of go in a different direction right now.
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今天我切入的角度會不太一樣
00:55
I hope you all realize that.
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希望各位已經感覺到了
00:58
So I'll just give you my message up front:
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那我就開門見山地講明主旨了
01:00
Try not to go extinct.
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請不要滅絕
01:02
(Laughter)
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(笑聲)
01:04
That's it.
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完了
01:06
(Laughter)
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(笑聲)
01:10
People ask me a lot --
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人們常常問我
01:12
in fact, one of the most asked questions I get
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事實上 我最常遇到的問題是
01:15
is, why do children like dinosaurs so much?
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爲什麽孩子們這麼喜歡恐龍？
01:19
What's the fascination?
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恐龍的魅力在哪？
01:21
And I usually just say,
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我通常只會說：
01:24
"Well dinosaurs were big,
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「呃 恐龍很大隻
01:26
different and gone."
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很特別、而且已經消失了」
01:29
They're all gone.
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全部消失了
01:31
Well that's not true,
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嗯，也不盡然如此
01:33
but we'll get to the goose in a minute.
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但我們等一下再來講這個
01:35
So that's sort of the theme:
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所以重點差不多就是這樣
01:38
big, different and gone.
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大隻、特別、消失了
01:42
The title of my talk:
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我演講的題目是：
01:44
Shape-shifting Dinosaurs:
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變形的恐龍
01:46
The Cause of a Premature Extinction.
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過早滅絕的原因
01:48
Now I assume that we remember dinosaurs.
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現在我假設各位都記得恐龍
01:51
And there's lots of different shapes.
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恐龍有各種體型
01:54
Lots of different kinds.
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許多種類
01:57
A long time ago,
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很久以前
01:59
back in the early 1900s,
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1900年代早期時
02:01
museums were out looking for dinosaurs.
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博物館競相尋找恐龍
02:04
They went out and gathered them up.
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他們四處尋找、搜集恐龍
02:07
And this is an interesting story.
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整件事情的發展非常有趣
02:09
Every museum wanted a little bigger or better one
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每個博物館都想要更大、更好的恐龍
02:12
than anybody else had.
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把其他博物館比下去
02:14
So if the museum in Toronto went out
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所以如果多倫多的博物館
02:17
and collected a Tyrannosaur, a big one,
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蒐集到一副暴龍的骸骨，大隻的暴龍
02:20
then the museum in Ottawa wanted a bigger one
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那麼渥太華的博物館就想要一隻更大
02:23
and a better one.
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更好的暴龍
02:25
And that happened for all museums.
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所有的博物館都打一樣的算盤
02:27
So everyone was out looking
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所以每個博物館都出動
02:29
for all these bigger and better dinosaurs.
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要找更大更好的恐龍骸骨
02:32
And this was in the early 1900s.
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這是1900年代早期的事
02:36
By about 1970,
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到了大約1970年代
02:39
some scientists were sitting around
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某些科學家聚在一起
02:41
and they thought, "What in the world?
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開始思索：「搞什麼鬼？
02:44
Look at these dinosaurs.
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「看看這些恐龍
02:46
They're all big.
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「全都這麼大隻
02:48
Where are all the little ones?"
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「小的恐龍哪去了？」
02:53
And they thought about it
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他們想了又想
02:55
and they even wrote papers about it:
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甚至還寫論文探討
02:57
"Where are the little dinosaurs?"
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「小型恐龍在哪兒？」
02:59
(Laughter)
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(笑聲)
03:07
Well, go to a museum, you'll see,
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去博物館看看吧
03:11
see how many baby dinosaurs there are.
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看你找不找得到小恐龍
03:14
People assumed -- and this was actually a problem --
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人們假定─其實這樣是有問題的─
03:17
people assumed
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不過人們假定
03:19
that if they had little dinosaurs,
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如果有小型恐龍
03:21
if they had juvenile dinosaurs,
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如果有年幼的恐龍
03:23
they'd be easy to identify.
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很容易就可以認出來
03:25
You'd have a big dinosaur
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反正就是一隻大隻的
03:27
and a littler dinosaur.
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和一隻小隻的
03:30
But all they had were big dinosaurs.
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但博物館收藏的都是大型恐龍
03:33
And it comes down to a couple of things.
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這顯示了幾件事
03:36
First off, scientists have egos,
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第一：科學家都自視甚高
03:40
and scientists like to name dinosaurs.
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而且喜歡替恐龍命名
03:44
They like to name anything.
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只要能被命名的他們都喜歡
03:46
Everybody likes to have their own animal that they named.
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大家都希望有自己命名、專屬於自己的動物
03:49
(Laughter)
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(笑聲)
03:52
And so every time they found something that looked a little different,
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所以每次他們找到一個看起來不一樣的東西
03:55
they named it something different.
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就會替它取一個不一樣的名字
03:58
And what happened, of course,
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當然最後就變成
04:00
is we ended up with a whole bunch of different dinosaurs.
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我們有了一大群不同的恐龍
04:05
In 1975,
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在1975年
04:08
a light went on in somebody's head.
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某人靈光一閃
04:11
Dr. Peter Dodson
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就是彼得‧德森
04:13
at the University of Pennsylvania
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一位賓州大學的博士
04:15
actually realized
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發現
04:18
that dinosaurs grew
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恐龍成長的方式
04:21
kind of like birds do,
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與鳥類有點相似
04:23
which is different
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而鳥類的成長方式
04:25
than the way reptiles grow.
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與爬蟲類不同
04:27
And in fact,
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事實上
04:29
he used the cassowary as an example.
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他拿食火雞當例子
04:32
And it's kind of cool -- if you look at the cassowary,
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還蠻酷的。如果你看食火雞
04:35
or any of the birds that have crests on their heads,
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或者其他頭上有冠的鳥類
04:38
they actually grow
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實際上
04:40
to about 80 percent adult size
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牠們在長到成年身型的80%時
04:42
before the crest starts to grow.
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頭上的冠才開始生長
04:45
Now think about that.
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各位想想
04:48
They're basically retaining their juvenile characteristics
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食火雞基本上長時間保留未成年的特徵
04:51
very late in what we call ontogeny.
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直到個體發生階段的晚期
04:54
So allometric cranial ontogeny
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所以異速頭顱個體發生
04:58
is relative skull growth.
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就是頭蓋骨的相對生長
05:01
So you can see
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所以各位可以看到
05:03
that if you actually found one
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如果你發現一隻
05:05
that was 80 percent grown
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只生長發育了80%的動物
05:08
and you didn't know that it was going to grow up to a cassowary,
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但你不知道牠會長成一隻食火雞
05:11
you would think they were two different animals.
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你就會以為牠是別的動物
05:15
So this was a problem,
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這就是問題所在
05:18
and Peter Dodson pointed this out
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彼得‧德森指出了這點
05:21
using some duck-billed dinosaurs
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他用的例子是某種鴨嘴恐龍
05:23
then called Hypacrosaurus.
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當時被稱為亞冠龍
05:25
And he showed
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他發現
05:27
that if you were to take a baby and an adult
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如果你用一隻幼年和一隻成年恐龍
05:30
and make an average of what it should look like,
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來計算這種恐龍在不同年齡的體型
05:33
if it grew in sort of a linear fashion,
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假設牠是以線性方式生長
05:36
it would have a crest
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牠就會有頭冠
05:38
about half the size of the adult.
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頭冠大小約是成年恐龍的一半
05:41
But the actual sub-adult
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但是實際上未成年的恐龍
05:43
at 65 percent
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只發育了65%的
05:45
had no crest at all.
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根本沒有頭冠
05:47
So this was interesting.
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所以這就有意思了
05:49
So this is where
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這就是
05:52
people went astray again.
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科學家的思路出錯的地方
05:55
I mean, if they'd have just taken that,
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我是說 如果他們可以接受
05:57
taken Peter Dodson's work, and gone on with that,
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接受彼得‧道森的研究結論，然後繼續往下發展
06:00
then we would have a lot less dinosaurs
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那麼我們的恐龍數目
06:02
than we have.
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就會大大減少
06:04
But scientists have egos;
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但是科學家自視甚高
06:06
they like to name things.
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又喜歡替事物命名
06:09
And so they went on naming dinosaurs
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所以他們繼續給恐龍命名
06:12
because they were different.
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因為牠們看上去不一樣
06:15
Now we have a way of actually testing
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不過呢，我們有方法可以確實測量
06:17
to see whether a dinosaur, or any animal,
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檢查恐龍或任何動物
06:20
is a young one or an older one.
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是年幼的還是較年長的
06:23
And that's by actually cutting into their bones.
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方法就是真的切骨見髓
06:26
But cutting into the bones of a dinosaur
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但是切開恐龍的骨頭
06:30
is hard to do, as you can imagine,
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是很困難的，各位想也知道
06:33
because in museums
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因為對博物館而言
06:36
bones are precious.
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恐龍骨頭很珍貴
06:40
You go into a museum and they take really good care of them.
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每個博物館都會非常小心地維護這些骨頭
06:43
They put them in foam, little containers.
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把骨頭放在小小的發泡容器中
06:46
They're very well taken care of.
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妥善收藏
06:50
They don't like it if you come in
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館方不會樂見你一進來
06:52
and want to saw them open and look inside.
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就打算鋸開骨頭看內部
06:54
(Laughter)
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(笑聲)
06:56
So they don't normally let you do that.
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所以他們通常不允許你這樣做
06:59
But I have a museum
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但是我有一個博物館
07:02
and I collect dinosaurs
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而且我也蒐集恐龍
07:04
and I can saw mine open.
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我可以鋸我自己的收藏
07:06
So that's what I do.
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我也這麼做了
07:08
(Applause)
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(掌聲)
07:13
So if you cut open a little dinosaur,
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如果你切開小恐龍的骨頭
07:18
it's very spongy inside like A.
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骨頭裡面疏鬆如海綿 像圖A
07:20
And if you cut into an older dinosaur,
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如果切開的骨頭是較年長恐龍
07:22
it's very massive.
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裡面十分緊密
07:24
You can tell it's mature bone.
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一看就知道是成熟的骨頭
07:26
So it's real easy to tell them apart.
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所以要區分骨頭是很容易的
07:29
So what I want to do
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現在
07:31
is show you these.
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讓各位看看這些東西
07:33
In North America in the Northern Plains of the United States
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在北美洲、美國的北美大平原
07:37
and the Southern Plains of Alberta and Saskatchewan,
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和加拿大亞伯達省和薩斯喀徹溫省的南部平原上
07:41
there's this unit of rock called the Hell Creek Formation
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有一處岩石區被稱為地獄溪地層
07:44
that produces the last dinosaurs that lived on Earth.
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從這裡找到了最後存活在地球上的恐龍
07:47
And there are 12 of them
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其中的12種
07:49
that everyone recognizes --
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是眾所周知的
07:51
I mean the 12 primary dinosaurs
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我指的是12種主要的恐龍
07:53
that went extinct.
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後來都滅絕了
07:55
And so we will evaluate them.
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因此我們測試這些恐龍
07:58
And that's sort of what I've been doing.
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這差不多就是我一直在從事的工作
08:00
So my students, my staff,
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我的學生、我的員工
08:03
we've been cutting them open.
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一直在鋸恐龍骨頭
08:06
Now as you can imagine,
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各位一定可以想像
08:08
cutting open a leg bone is one thing,
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切開腿骨是一回事
08:10
but when you go to a museum
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但當你走進一間博物館
08:13
and say, "You don't mind if I cut open
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說：「你們應該不介意
08:15
your dinosaur's skull do you?"
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「我切開貴館恐龍的頭骨吧？」
08:18
they say, "Go away."
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館員會說：「滾開」
08:21
(Laughter)
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(笑聲)
08:26
So here are 12 dinosaurs.
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這就是那12種恐龍
08:30
And we want to look at these three first.
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我們先看這三種
08:33
So these are dinosaurs that are called Pachycephalosaurs.
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這些恐龍被稱為腫頭龍
08:36
And everybody knows
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大家都知道
08:38
that these three animals are related.
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這三種恐龍是親戚
08:40
And the assumption is
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我們假設
08:42
is that they're related
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牠們的血緣關係
08:44
like cousins or whatever.
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是類似堂兄弟之類的
08:47
But no one ever considered
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但沒有人想過
08:49
that they might be more closely related.
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牠們可能有更緊密的關係
08:52
In other words,
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換句話說
08:54
people looked at them and they saw the differences.
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科學家觀察牠們 看到了不同之處
08:57
And you all know
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大家都知道
08:59
that if you are going to determine
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如果你要確定
09:01
whether you're related to your brother or your sister,
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你跟你的兄弟姐妹有沒有血緣關係
09:03
you can't do it by looking at differences.
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不能只根據你們的相異之處做判斷
09:07
You can only determine relatedness
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要確認血緣關係
09:09
by looking for similarities.
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要從相似之處下手
09:11
So people were looking at these
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因此人們看著這些恐龍時
09:13
and they were talking about how different they are.
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總是只注意牠們有多麼不同
09:15
Pachycephalosaurus has a big, thick dome on its head,
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腫頭龍的頭上 有一個又大又厚的圓頂
09:18
and it's got some little bumps on the back of its head,
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頭部背面有一些小的凸起物
09:21
and it's got a bunch of gnarly things on the end of its nose.
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鼻子末端有一堆瘤狀物
09:25
And then Stygimoloch, another dinosaur
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這是冥河龍 另一種恐龍
09:27
from the same age, lived at the same time,
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跟腫頭龍生存的時代相同
09:31
has spikes sticking out the back of its head.
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牠的頭部後面有棘突出
09:33
It's got a little, tiny dome,
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頭上有個很小的圓頂
09:35
and it's got a bunch of gnarly stuff on its nose.
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而且鼻子上也有一堆瘤狀物
09:39
And then there's this thing called Dracorex,
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然後這隻是名為龍王龍的傢伙
09:41
Hogwart's Eye.
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霍格華茲的眼睛
09:43
Guess where that came from? Dragon.
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猜猜牠的名字源自哪裡？龍
09:46
So here's a dinosaur
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這頭恐龍
09:48
that has spikes sticking out of its head, no dome
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頭上有棘 沒有圓頂
09:51
and gnarly stuff on its nose.
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鼻子上有瘤狀物
09:54
Nobody noticed the gnarly stuff sort of looked alike.
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沒人注意到這些瘤狀物有點相似
09:57
But they did look at these three
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但人們看著這三隻恐龍
09:59
and they said, "These are three different dinosaurs,
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心裡想：「這是三種不同的恐龍
10:01
and Dracorex is probably the most primitive of them.
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「龍王龍也許是其中最原始的
10:04
And the other one is more primitive than the other.
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這隻比另一隻更早期一點」
10:07
It's unclear to me
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我不是很確定
10:10
how they actually sorted these three of them out.
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他們究竟是怎麼挑出這三種恐龍的
10:13
But if you line them up,
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但如果你把牠們一字排開
10:15
if you just take those three skulls and just line them up,
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把牠們的頭骨排成一列
10:18
they line up like this.
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排起來會像這樣
10:20
Dracorex is the littlest one,
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龍王龍的最小
10:22
Stygimoloch is the middle size one,
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冥河龍在中間
10:24
Pachycephalosaurus is the largest one.
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腫頭龍是最大的
10:27
And one would think,
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你們可能認為
10:29
that should give me a clue.
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這應該很明顯了吧
10:31
(Laughter)
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(笑聲)
10:33
But it didn't give them a clue.
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但科學家什麼都沒察覺
10:36
Because, well we know why.
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我們都知道為什麼
10:39
Scientists like to name things.
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因為科學家喜歡替東西命名
10:42
So if we cut open
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所以如果我們
10:44
Dracorex --
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對龍王龍下手
10:46
I cut open our Dracorex --
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把我們的龍王龍鋸開
10:48
and look, it was spongy inside,
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你看 骨頭裡面是海綿狀的
10:50
really spongy inside.
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非常明顯的海綿
10:52
I mean, it is a juvenile
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意思是說牠還年幼
10:54
and it's growing really fast.
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而且長得很快
10:56
So it is going to get bigger.
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所以牠會長得更大
10:58
If you cut open Stygimoloch,
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如果你鋸開冥河龍
11:00
it is doing the same thing.
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也會發現一樣的事情
11:02
The dome, that little dome,
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那個小小的圓頂
11:04
is growing really fast.
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長得非常快
11:06
It's inflating very fast.
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迅速地膨脹
11:08
What's interesting is the spike on the back of the Dracorex
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有趣的是 龍王龍背上的棘
11:11
was growing very fast as well.
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也長得非常快
11:13
The spikes on the back of the Stygimoloch
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冥河龍背上的棘
11:15
are actually resorbing,
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其實在萎縮
11:17
which means they're getting smaller
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也就是越變越小
11:19
as that dome is getting bigger.
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而頭上的圓頂則越變越大
11:21
And if we look at Pachycephalosaurus,
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如果我們看看腫頭龍
11:24
Pachycephalosaurus has a solid dome
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牠頭上有堅硬的圓頂
11:27
and its little bumps on the back of its head
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頭部背面的凸起物
11:30
were also resorbing.
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也在萎縮
11:32
So just with these three dinosaurs,
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因此只要看這三種恐龍
11:34
you can easily -- as a scientist --
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科學家很容易就能夠
11:36
we can easily hypothesize
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做出假設
11:38
that it is just a growth series
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牠們代表不同的成長階段
11:40
of the same animal.
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其實都是同一種動物
11:43
Which of course means
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當然這就表示
11:46
that Stygimoloch and Dracorex
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冥河龍和龍王龍
11:50
are extinct.
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都絕種了
11:52
(Laughter)
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(笑聲)
11:57
Okay.
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好吧
12:01
Which of course means
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當然這就表示
12:04
we have 10 primary dinosaurs to deal with.
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我們有10種主要恐龍要對付
12:08
So a colleague of mine at Berkley,
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因此我在柏克萊的一位同事
12:10
he and I were looking at Triceratops.
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和我一起研究三觭龍
12:13
And before the year 2000 --
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2000年之前
12:15
now remember,
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請記住
12:17
Triceratops was first found in the 1800s --
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三觭龍最初是在1800年代發現的
12:19
before 2000, no one had ever seen
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在2000年之前 沒有人看過
12:22
a juvenile Triceratops.
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幼年的三觭龍
12:25
There's a Triceratops in every museum in the world,
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全世界每座博物館都有一隻三觭龍
12:28
but no one had ever collected a juvenile.
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但不曾有人找到幼年三觭龍過
12:32
And we know why, right?
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我們都知道為什麼，對吧？
12:34
Because everybody wants to have a big one.
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因為每個人都想要大隻的
12:37
So everyone had a big one.
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所以大家的都是大隻的
12:39
So we went out and collected a whole bunch of stuff
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我們去考古時找到一大堆東西
12:41
and we found a whole bunch of little ones.
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一大堆小三觭龍的骸骨
12:43
They're everywhere. They're all over the place.
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到處都是，遍佈整個區域
12:47
So we have a whole bunch of them at our museum.
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因此我們博物館裡有一大堆
12:49
(Laughter)
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(笑聲)
12:54
And everybody says it's because I have a little museum.
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大家都說這是因為我有一座小博物館
12:56
When you have a little museum, you have little dinosaurs.
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當你有小博物館，你就會有小恐龍
12:59
(Laughter)
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(笑聲)
13:02
If you look at the Triceratops,
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如果各位觀察三觭龍
13:04
you can see it's changing, it's shape-shifting.
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就會發現牠在改變 變形
13:06
As the juveniles are growing up,
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當幼年的個體長大時
13:08
their horns actually curve backwards.
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牠們的角會往後彎
13:10
And then as they grow older,
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接著越長越大之後
13:12
the horns grow forward.
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角會再往前彎
13:14
And that's pretty cool.
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還蠻酷的
13:16
If you look along the edge of the frill,
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請各位看看頭骨的邊緣
13:18
they have these little triangular bones
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上面三角狀的小骨頭
13:21
that actually grow big as triangles
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會長大變成三角形
13:23
and then they flatten against the frill
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然後在邊緣扁下去變平
13:26
pretty much like the spikes do
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就像剛剛講過的棘一樣
13:28
on the Pachycephalosaurs.
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長在腫頭龍背上的棘
13:31
And then, because the juveniles are in my collection,
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然後因為我有蒐集幼年三觭龍
13:35
I cut them open
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我就把牠們鋸開
13:37
and look inside.
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觀察內部
13:39
And the little one is really spongy.
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小隻的恐龍骨頭裡面很像海綿
13:42
And the middle size one is really spongy.
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中型的也很像海綿
13:45
But what was interesting
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有趣的是
13:47
was the adult Triceratops was also spongy.
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成年的三觭龍 骨頭內部也像海綿
13:49
And this is a skull that is two meters long.
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這副頭蓋骨有兩公尺長
13:52
It's a big skull.
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是非常大的頭
13:55
But there's another dinosaur
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但還有另一種恐龍
13:57
that is found in this formation
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樣子也長這樣
14:00
that looks like a Triceratops, except it's bigger,
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長得像三觭龍 但是更大隻
14:03
and it's called Torosaurus.
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叫做牛角龍
14:06
And Torosaurus, when we cut into it,
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當我們把牛角龍切開時
14:09
has mature bone.
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發現牠有成熟的骨頭
14:11
But it's got these big holes in its shield.
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不過牠的頭盾上有大洞
14:13
And everybody says, "A Triceratops and a Torosaurus
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大家都說三觭龍和牛角龍
14:16
can't possibly be the same animal
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不可能是同一種動物
14:18
because one of them's bigger than the other one."
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因為牛角龍比三觭龍大
14:20
(Laughter)
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(笑聲)
14:25
"And it has holes in its frill."
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頭盾上還有洞
14:27
And I said, "Well do we have any juvenile Torosauruses?"
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我說：「呃，那我們有幼年的牛角龍嗎？」
14:30
And they said, "Well no,
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他們回答：「嗯，沒有」
14:33
but it has holes in its frill."
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「但是牠的頭盾上有洞」
14:36
So one of my graduate students, John Scannella,
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因此我的一位研究生約翰‧史坎納拉
14:39
looked through our whole collection
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研究了我們所有的蒐藏
14:41
and he actually discovered
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赫然發現
14:43
that the hole starting to form
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這些洞的成形
14:45
in Triceratops
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源自三觭龍
14:47
and, of course it's open, in Torosaurus --
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當然在牛角龍頭上已經是完整的洞
14:50
so he found the transitional ones
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所以他發現的恐龍
14:53
between Triceratops and Torosaurus,
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處於三觭龍和牛角龍之間的過渡時期
14:55
which was pretty cool.
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還蠻酷的
14:57
So now we know
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因此現在我們知道
14:59
that Torosaurus
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牛角龍
15:01
is actually a grownup Triceratops.
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其實是成年的三觭龍
15:04
Now when we name dinosaurs,
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當我們在替恐龍命名
15:06
when we name anything,
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或任何其他東西命名時
15:08
the original name gets to stick
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第一個名字都會長存
15:10
and the second name is thrown out.
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第二個名字都會被遺忘
15:14
So Torosaurus is extinct.
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因此牛角龍也滅絕了
15:17
Triceratops, if you've heard the news,
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如果你有看新聞，講到三觭龍時
15:20
a lot of the newscasters got it all wrong.
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很多新聞記者根本大錯特錯
15:22
They thought Torosaurus should be kept and Triceratops thrown out,
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他們認為應該保留牛角龍，剔除三觭龍
15:25
but that's not going to happen.
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但這是不可能發生的
15:27
(Laughter)
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(笑聲)
15:33
All right, so we can do this with a bunch of dinosaurs.
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所以說 我們可以對許多恐龍做同樣的事
15:36
I mean, here's Edmontosaurus
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像是這隻埃德蒙頓龍
15:38
and Anatotitan.
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和大鴨龍
15:40
Anatotitan: giant duck.
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大鴨龍：巨大的鴨子
15:43
It's a giant duck-bill dinosaur.
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是一種大型的鴨嘴龍
15:45
Here's another one.
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牠們是另一個例子
15:47
So we look at the bone histology.
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我們以組織學的角度觀察骨頭
15:49
The bone histology tells us
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骨骼組織學顯示
15:52
that Edmontosaurus is a juvenile,
355
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埃德蒙頓龍是幼年恐龍
15:54
or at least a sub-adult,
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或至少是未成年的
15:56
and the other one is an adult
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另一隻則是成年恐龍
15:59
and we have an ontogeny.
358
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個體發生歷程很完備
16:02
And we get rid of Anatotitan.
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因此大鴨龍也不存在了
16:05
So we can just keep doing this.
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我們一直重複這個過程
16:08
And the last one
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到最後一種恐龍
16:10
is T. Rex.
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暴龍
16:12
So there's these two dinosaurs,
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這裡有兩隻恐龍
16:14
T. Rex and Nanotyrannus.
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暴龍和矮暴龍
16:17
(Laughter)
365
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(笑聲)
16:19
Again, makes you wonder.
366
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又來了，真讓人疑惑
16:22
(Laughter)
367
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(笑聲)
16:25
But they had a good question.
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但科學家問了個好問題
16:27
They were looking at them
369
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他們觀察這兩隻恐龍
16:29
and they said, "One's got 17 teeth, and the biggest one's got 12 teeth.
370
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說 小隻有17顆牙 大隻的有12顆牙
16:32
And that doesn't make any sense at all,
371
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這完全沒有道理
16:34
because we don't know of any dinosaurs
372
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因為我們從未發現有哪一種恐龍
16:36
that gain teeth as they get older.
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年紀越大 牙齒會越多
16:38
So it must be true --
374
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因此事實擺在眼前
16:40
they must be different."
375
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牠們一定不一樣
16:43
So we cut into them.
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所以我們鋸開恐龍
16:45
And sure enough,
377
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果真
16:47
Nanotyrannus has juvenile bone
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矮暴龍的骨頭是幼年的
16:50
and the bigger one has more mature bone.
379
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3000
暴龍的骨頭較成熟
16:53
It looks like it could still get bigger.
380
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似乎還可以長更大
16:56
And at the Museum of the Rockies where we work,
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然後 在我們工作的洛磯山脈博物館
16:58
I have four T. Rexes,
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有四隻暴龍
17:00
so I can cut a whole bunch of them.
383
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我可以把牠們通通鋸開
17:02
But I didn't have to cut any of them really,
384
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但實際上不用這麼做
17:05
because I just lined up their jaws
385
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因為我只要把牠們的下巴排開
17:08
and it turned out the biggest one had 12 teeth
386
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就會發現 最大隻的有12顆牙
17:11
and the next smallest one had 13
387
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2000
第二大的有13顆牙
17:13
and the next smallest had 14.
388
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第三大的有14顆牙
17:15
And of course, Nano has 17.
389
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當然 矮暴龍有17顆牙
17:17
And we just went out and looked at other people's collections
390
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所以我們就去看其他人的蒐藏
17:20
and we found one that has sort of 15 teeth.
391
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發現有一隻恐龍似乎有15顆牙
17:24
So again, real easy to say
392
1029000
3000
因此很容易得到結論
17:27
that Tyrannosaurus ontogeny
393
1032000
2000
就是暴龍的個體發生歷程
17:29
included Nanotyrannus,
394
1034000
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包括矮暴龍
17:32
and therefore we can take out another dinosaur.
395
1037000
5000
因此我們又要跟一種恐龍說拜拜了
17:37
(Laughter)
396
1042000
2000
(笑聲)
17:39
So when it comes down
397
1044000
4000
因此
17:43
to our end cretaceous,
398
1048000
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到白堊紀末期
17:45
we have seven left.
399
1050000
3000
我們只剩七種恐龍
17:48
And that's a good number.
400
1053000
3000
很好的數字
17:51
That's a good number to go extinct, I think.
401
1056000
3000
很適合絕種 我覺得啦
17:54
Now as you can imagine,
402
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各位可以想像
17:56
this is not very popular with fourth-graders.
403
1061000
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國小四年級生肯定大失所望
17:59
Fourth-graders love their dinosaurs,
404
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小四生很愛恐龍
18:01
they memorize them.
405
1066000
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每一種都如數家珍
18:06
And they're not happy with this.
406
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聽到這個一定會很沮喪
18:09
(Laughter)
407
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(笑聲)
18:11
Thank you very much.
408
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謝謝各位
18:13
(Applause)
409
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(掌聲)
ABOUT THE SPEAKER
Jack Horner - Dinosaur diggerJack Horner and his dig teams have discovered the first evidence of parental care in dinosaurs, extensive nesting grounds, evidence of dinosaur herds, and the world’s first dinosaur embryos. He's now exploring how to build a dinosaur.
Why you should listen
Paleontologist Jack Horner discovered the first dinosaur eggs in the Western Hemisphere, the first evidence of dinosaur colonial nesting, the first evidence of parental care among dinosaurs, and the first dinosaur embryos.
Horner's research covers a wide range of topics about dinosaurs, including their behavior, physiology, ecology and evolution. Due to struggles with the learning disability, dyslexia, Horner does not hold a formal college degree but was awarded an Honorary Doctorate of Science from the University of Montana in 1986. Also in 1986 he was awarded a MacArthur Fellowship.
He's the Curator of Paleontology at the Museum of the Rockies in Bozeman, Montana, and is widely acknowledged to be the inspiration for the main character in the book and film Jurassic Park.
Jack Horner | Speaker | TED.com