TED2008
Peter Ward: A theory of Earth's mass extinctions
彼得沃德所發表的大滅絕
Filmed:
Readability: 3.9
1,130,090 views
小行星的撞擊得到所有覆蓋面 ,但"美狄亞假說"的作者彼得沃德則認為大部分發生在地球上的大滅絕是因微小的細菌. 肇事者是一種叫硫化氫的毒藥,它可能對藥物應用有意外的貢獻.
Peter Ward - Paleontologist
Peter D. Ward studies life on Earth -- where it came from, how it might end, and how utterly rare it might be. Full bio
Peter D. Ward studies life on Earth -- where it came from, how it might end, and how utterly rare it might be. Full bio
Double-click the English transcript below to play the video.
00:18
So, I want to start out with
0
0
2000
好,我先由
00:20
this beautiful picture from my childhood.
1
2000
2000
我這幅美麗的童年照開始講起
00:22
I love the science fiction movies.
2
4000
2000
我喜愛看科幻電影
00:24
Here it is: "This Island Earth."
3
6000
2000
這套: "飛碟征空"
00:26
And leave it to Hollywood to get it just right.
4
8000
2000
最適合在美國荷里活上映.
00:28
Two-and-a-half years in the making.
5
10000
2000
用了兩年半的時間製作.
00:30
(Laughter)
6
12000
3000
(笑聲)
00:33
I mean, even the creationists give us 6,000,
7
15000
3000
我是說,當時創作人給了我們$6000
00:36
but Hollywood goes to the chase.
8
18000
2000
但荷里活緊緊跟隨
00:38
And in this movie, we see what we think is out there:
9
20000
4000
還有在這電影裡, 我們看到所認為的外太空:
00:42
flying saucers and aliens.
10
24000
3000
飛碟和外星人.
00:45
Every world has an alien, and every alien world has a flying saucer,
11
27000
3000
每個世界都有外星人, 而每個外星人世界都有飛碟,
00:48
and they move about with great speed. Aliens.
12
30000
4000
他們行動很快捷. 外星人.
00:53
Well, Don Brownlee, my friend, and I finally got to the point
13
35000
3000
我和我的朋友唐布朗利都覺得
00:56
where we got tired of turning on the TV
14
38000
3000
我們厭倦開電視
00:59
and seeing the spaceships and seeing the aliens every night,
15
41000
3000
每一晚都看著太空船和外星人
01:02
and tried to write a counter-argument to it,
16
44000
3000
也厭倦寫有關外太空正反觀點
01:05
and put out what does it really take for an Earth to be habitable,
17
47000
4000
改為想有什麼條件令地球適合居住
01:09
for a planet to be an Earth, to have a place
18
51000
2000
就是地球, 不單有地方住
01:11
where you could probably get not just life, but complexity,
19
53000
3000
能讓人生存, 更有複雜性
01:14
which requires a huge amount of evolution,
20
56000
2000
這需要長時間的進化
01:16
and therefore constancy of conditions.
21
58000
3000
所以需要環境的稳定性
01:19
So, in 2000 we wrote "Rare Earth." In 2003, we then asked,
22
61000
3000
所以2000年我們寫了 "Rare Earth". 在2003年,我們便說
01:22
let's not think about where Earths are in space, but how long has Earth been Earth?
23
64000
5000
不要只想著地球在太空的位置,而去想想地球有幾長時間為地球
01:27
If you go back two billion years,
24
69000
2000
如果你回到20億年前,
01:29
you're not on an Earth-like planet any more.
25
71000
2000
那行星不像你今日所見的地球
01:31
What we call an Earth-like planet is actually a very short interval of time.
26
73000
4000
我們所稱為地球的行星其實很年輕
01:35
Well, "Rare Earth" actually
27
77000
2000
在"Rare Earth"裡
01:37
taught me an awful lot about meeting the public.
28
79000
3000
教導我極多關於面對群眾的要訣
01:40
Right after, I got an invitation to go to a science fiction convention,
29
82000
3000
有次我收到一個科幻電影會展的邀請
01:43
and with all great earnestness walked in.
30
85000
3000
我帶著一股熱誠步入場地
01:46
David Brin was going to debate me on this,
31
88000
2000
David Brin 正在與我爭辯
01:48
and as I walked in, the crowd of a hundred started booing lustily.
32
90000
4000
當我行入會塲,幾百人開始發出很大的噓聲
01:52
I had a girl who came up who said, "My dad says you're the devil."
33
94000
3000
有個小女孩走到我面前說:"我爸說你是一個魔鬼."
01:55
You cannot take people's aliens away from them
34
97000
4000
你不可以從別人身上取走外星人
01:59
and expect to be anybody's friends.
35
101000
4000
然後同所有人做朋友.
02:03
Well, the second part of that, soon after --
36
105000
2000
第二部分,這之後..
02:05
and I was talking to Paul Allen; I saw him in the audience,
37
107000
3000
我和Paul Allen 聊天,因我在觀眾席見到他
02:08
and I handed him a copy of "Rare Earth."
38
110000
2000
我給他一本"Rare Earth"
02:10
And Jill Tarter was there, and she turned to me,
39
112000
4000
Jill Tarter 聽到,她臉向我
02:14
and she looked at me just like that girl in "The Exorcist."
40
116000
3000
她看我的表情就像剛才那女孩在看"驅魔人"
02:17
It was, "It burns! It burns!"
41
119000
2000
就像說"著火了!著火了!"
02:19
Because SETI doesn't want to hear this.
42
121000
2000
因為SETI不想聽到這話. (SEIT: Search for Extra-Terrestrial Intelligence 尋找外太空星球智慧生命計畫)
02:21
SETI wants there to be stuff out there.
43
123000
3000
SETI一直想在太空找到外星人
02:24
I really applaud the SETI efforts, but we have not heard anything yet.
44
126000
3000
我要為SETI的努力鼓掌,但我們未聽到什麼消息.
02:27
And I really do think we have to start thinking
45
129000
2000
我真的認為我們要開始思考
02:29
about what's a good planet and what isn't.
46
131000
3000
怎樣才是一個好或不好的行星
02:32
Now, I throw this slide up because it indicates to me that,
47
134000
3000
現在我放這投影片因它向我顯示
02:35
even if SETI does hear something, can we figure out what they said?
48
137000
4000
就算SETI真的聽到什麼,我們如何理解那些話?
02:39
Because this was a slide that was passed
49
141000
2000
因為這張投影片經過
02:41
between the two major intelligences on Earth -- a Mac to a PC --
50
143000
4000
兩個地球上智能產品 -- Mac 和 PC
02:45
and it can't even get the letters right --
51
147000
3000
但它們都不能辨認那些字
02:48
(Laughter)
52
150000
2000
(笑聲)
02:50
-- so how are we going to talk to the aliens?
53
152000
2000
所以我們如何和外星人溝通?
02:52
And if they're 50 light years away, and we call them up,
54
154000
3000
如果他們在50光年以外,而我們打電話給他們
02:55
and you blah, blah, blah, blah, blah,
55
157000
2000
然後你叭啦叭啦說了一大堆
02:57
and then 50 years later it comes back and they say, Please repeat?
56
159000
3000
50年後訊號回來是:請再說一遍
03:00
I mean, there we are.
57
162000
2000
所以我們就是這樣
03:02
Our planet is a good planet because it can keep water.
58
164000
3000
我們的地球是一個好行星因它能儲存水.
03:05
Mars is a bad planet, but it's still good enough for us to go there
59
167000
4000
火星是一個差的行星但它仍可接受
03:09
and to live on its surface if we're protected.
60
171000
2000
如果我們受到保護就可以住在它的表面
03:11
But Venus is a very bad -- the worst -- planet.
61
173000
3000
但金星很差-最差-的行星
03:14
Even though it's Earth-like, and even though early in its history
62
176000
3000
就算它外表像地球,就算它以前
03:17
it may very well have harbored Earth-like life,
63
179000
3000
可能有海洋生態
03:20
it soon succumbed to runaway greenhouse --
64
182000
3000
它最終敗合一發不可收拾的溫室效應
03:23
that's an 800 degrees [Fahrenheit] surface --
65
185000
2000
攝氏800度的表面
03:25
because of rampant carbon dioxide.
66
187000
3000
因為二氧化碳的泛濫
03:28
Well, we know from astrobiology that we can really now predict
67
190000
3000
我們從天體生物學裡能預測
03:31
what's going to happen to our particular planet.
68
193000
3000
地球將會發生的事
03:34
We are right now in the beautiful Oreo
69
196000
3000
我們正處於這漂亮的Oreo時期
03:37
of existence -- of at least life on Planet Earth --
70
199000
3000
可能是地球上最後存在的生物
03:40
following the first horrible microbial age.
71
202000
3000
接著是可怕的微生物時代
03:43
In the Cambrian explosion, life emerged from the swamps,
72
205000
3000
寒武紀大爆發時生物從沼澤出來
03:46
complexity arose,
73
208000
2000
成為更複雜的生物
03:48
and from what we can tell, we're halfway through.
74
210000
3000
由此可見我們己經歷了一半
03:51
We have as much time for animals to exist on this planet
75
213000
3000
動物在地球上一早生存著
03:54
as they have been here now,
76
216000
2000
就如現況
03:56
till we hit the second microbial age.
77
218000
2000
直至我們經歷第二次微生物時代
03:58
And that will happen, paradoxically --
78
220000
2000
接著反常態的情況-
04:00
everything you hear about global warming --
79
222000
2000
所有你聽到有關全球暖化-
04:02
when we hit CO2 down to 10 parts per million,
80
224000
3000
當減少二氧化碳到百萬分之十
04:05
we are no longer going to have to have plants
81
227000
2000
我們便不再有植物
04:07
that are allowed to have any photosynthesis, and there go animals.
82
229000
4000
產生光合作用,然後動物也沒有
04:11
So, after that we probably have seven billion years.
83
233000
2000
之後估計我們會有70億年時間
04:13
The Sun increases in its intensity, in its brightness,
84
235000
3000
太陽會更猛烈更光
04:16
and finally, at about 12 billion years after it first started,
85
238000
5000
最後,120億年後
04:21
the Earth is consumed by a large Sun,
86
243000
3000
地球會被太陽取代
04:24
and this is what's left.
87
246000
3000
這是所剩下的
04:27
So, a planet like us is going to have an age and an old age,
88
249000
4000
因行星就如我們有年輕和年老
04:31
and we are in its golden summer age right now.
89
253000
4000
而我們正處於它的黃金時期
04:35
But there's two fates to everything, isn't there?
90
257000
2000
但凡事都有兩面不是嗎?
04:37
Now, a lot of you are going to die of old age,
91
259000
3000
很多人都在年老時才去世
04:40
but some of you, horribly enough, are going to die in an accident.
92
262000
3000
但有些人,很慘,因他們是死於意外
04:43
And that's the fate of a planet, too.
93
265000
2000
這也是行星的命運
04:45
Earth, if we're lucky enough -- if it doesn't get hit by a Hale-Bopp,
94
267000
4000
如果我們夠幸運,在未來70億年內不被彗星Hale-Bopp
04:49
or gets blasted by some supernova nearby
95
271000
4000
或附近的超新星擊中
04:53
in the next seven billion years -- we'll find under your feet.
96
275000
3000
我們腳下的地球仍在
04:56
But what about accidental death?
97
278000
2000
但那意外性的死亡呢?
04:58
Well, paleontologists for the last 200 years
98
280000
2000
古生物學家在過去200年
05:00
have been charting death. It's strange --
99
282000
2000
不斷記錄死亡數據. 很奇怪
05:02
extinction as a concept wasn't even thought about
100
284000
3000
沒有人對絕種這概念有深入研究
05:05
until Baron Cuvier in France found this first mastodon.
101
287000
3000
直至法國的Baron Cuvier 發現第一隻乳齒象
05:08
He couldn't match it up to any bones on the planet,
102
290000
2000
他不能找到地球上找到相類似的骸骨
05:10
and he said, Aha! It's extinct.
103
292000
2000
所以他說:呀哈!這已經絕種
05:12
And very soon after, the fossil record started yielding
104
294000
3000
不久,化石記錄變得更齊全
05:15
a very good idea of how many plants and animals there have been
105
297000
3000
有一個很好的主意,估計多少種動植物
05:18
since complex life really began to leave
106
300000
2000
只從複雜的生命體開始留下
05:20
a very interesting fossil record.
107
302000
3000
一些很有趣的化石記錄
05:23
In that complex record of fossils,
108
305000
3000
在這齊全的化石記錄
05:26
there were times when lots of stuff
109
308000
2000
發現有很多物種
05:28
seemed to be dying out very quickly,
110
310000
2000
很快便全部死亡
05:30
and the father/mother geologists
111
312000
2000
地質學家"之父"或"之母"
05:32
called these "mass extinctions."
112
314000
2000
稱此為"大滅絕"
05:34
All along it was thought to be either an act of God
113
316000
2000
有人猜想這可能是神的作為
05:36
or perhaps long, slow climate change,
114
318000
2000
或許是更漫長的氣候變化
05:38
and that really changed in 1980,
115
320000
2000
直到1980年有了改變
05:40
in this rocky outcrop near Gubbio,
116
322000
3000
在古比奧附近的岩石面
05:43
where Walter Alvarez, trying to figure out
117
325000
3000
Walter Alvarez希望在這裡弄清楚
05:46
what was the time difference between these white rocks,
118
328000
3000
這些白色的岩石是出現在那個時期
05:49
which held creatures of the Cretaceous period,
119
331000
2000
那些岩石是白堊時期
05:51
and the pink rocks above, which held Tertiary fossils.
120
333000
2000
有些粉色的是第三紀化石.
05:53
How long did it take to go from one system to the next?
121
335000
4000
從一個時期到另一個需要多長時間?
05:57
And what they found was something unexpected.
122
339000
2000
他們發現一些意料之外的事
05:59
They found in this gap, in between, a very thin clay layer,
123
341000
3000
他們發現有一個隙縫中有一層很薄的黏土層
06:02
and that clay layer -- this very thin red layer here --
124
344000
3000
那黏土層有一層很薄的紅色表層
06:05
is filled with iridium.
125
347000
2000
裡面充滿銥
06:07
And not just iridium; it's filled with glassy spherules,
126
349000
3000
不單止銥; 還有玻璃球粒
06:10
and it's filled with quartz grains
127
352000
2000
和石英顆粒
06:12
that have been subjected to enormous pressure: shock quartz.
128
354000
4000
曾遭受很大的壓力壓下去:撞擊石英
06:16
Now, in this slide the white is chalk,
129
358000
2000
在這投影片白色的部分是白堊
06:18
and this chalk was deposited in a warm ocean.
130
360000
3000
白堊是在溫暖的海洋沈澱
06:21
The chalk itself's composed by plankton
131
363000
2000
由浮游生物組成
06:23
which has fallen down from the sea surface onto the sea floor,
132
365000
4000
浮游生物由海面沉到海底
06:27
so that 90 percent of the sediment here is skeleton of living stuff,
133
369000
3000
所以有九成的沈積物是生物的骸骨
06:30
and then you have that millimeter-thick red layer,
134
372000
2000
你們看見幾毫米厚的紅色層
06:32
and then you have black rock.
135
374000
2000
然後是黑色的石頭
06:34
And the black rock is the sediment on the sea bottom
136
376000
3000
黑石頭是海藏的沉積物
06:37
in the absence of plankton.
137
379000
2000
並沒有浮游生物
06:39
And that's what happens in an asteroid catastrophe,
138
381000
4000
小行星撞擊地球時,
06:43
because that's what this was, of course. This is the famous K-T.
139
385000
3000
就是因為這事,當然就是著名的K-T
06:46
A 10-kilometer body hit the planet.
140
388000
2000
一個十公里大的星體撞擊行星.
06:48
The effects of it spread this very thin impact layer all over the planet,
141
390000
4000
這現象導致全個行星蒙一層薄薄的土層
06:52
and we had very quickly the death of the dinosaurs,
142
394000
3000
之後恐龍開始死亡
06:55
the death of these beautiful ammonites,
143
397000
2000
還有這些美麗的鸚鵡螺化石
06:57
Leconteiceras here, and Celaeceras over here,
144
399000
2000
這是Leconteiceras,那是Celaeceras(兩者都是化石的一種)
06:59
and so much else.
145
401000
2000
還有很多
07:01
I mean, it must be true,
146
403000
2000
我意思是,這肯定是真的
07:03
because we've had two Hollywood blockbusters since that time,
147
405000
3000
因從那時起荷里活有兩套風靡一時的電影
07:06
and this paradigm, from 1980 to about 2000,
148
408000
3000
這例子在1980 至2000年期間
07:09
totally changed how we geologists thought about catastrophes.
149
411000
5000
完全改變了地質學家對行星撞擊的想法
07:14
Prior to that, uniformitarianism was the dominant paradigm:
150
416000
3000
之前均變說是主要的學說:
07:17
the fact that if anything happens on the planet in the past,
151
419000
3000
事實是如果行星以前發生了什麼事
07:20
there are present-day processes that will explain it.
152
422000
4000
都會成為當代的理論
07:24
But we haven't witnessed a big asteroid impact,
153
426000
3000
但我們沒有親眼目睹一個大的小行星撞擊的影響
07:27
so this is a type of neo-catastrophism,
154
429000
2000
這是新災變論其中一種
07:29
and it took about 20 years for the scientific establishment
155
431000
3000
科學家用了20年的時間才能
07:32
to finally come to grips: yes, we were hit;
156
434000
2000
確定:是, 地球曾被撞擊
07:34
and yes, the effects of that hit caused a major mass extinction.
157
436000
4000
而這撞擊導致大滅絕
07:39
Well, there are five major mass extinctions
158
441000
2000
一共有五次主要的大滅絕
07:41
over the last 500 million years, called the Big Five.
159
443000
3000
在過去的五億年, 它們被稱為 Big Five (大五)
07:44
They range from 450 million years ago
160
446000
3000
由4.5億年前
07:47
to the last, the K-T, number four,
161
449000
2000
到最後, K-T, 第四個
07:49
but the biggest of all was the P, or the Permian extinction,
162
451000
4000
但最嚴重是P, 或作二疊紀滅絕
07:53
sometimes called the mother of all mass extinctions.
163
455000
2000
有時被稱為大滅絕之母
07:55
And every one of these has been subsequently blamed
164
457000
3000
而每次大滅絕也歸咎於
07:58
on large-body impact.
165
460000
2000
龐大行星帶來的影響
08:00
But is this true?
166
462000
2000
但是否屬實?
08:03
The most recent, the Permian, was thought to have been an impact
167
465000
3000
最近二疊紀滅絕有個影響
08:06
because of this beautiful structure on the right.
168
468000
2000
因這右面美麗的生物
08:08
This is a Buckminsterfullerene, a carbon-60.
169
470000
3000
這是巴克敏斯特富勒烯,碳60的一種
08:11
Because it looks like those terrible geodesic domes
170
473000
3000
因它看來像我60年代心愛的
08:14
of my late beloved '60s,
171
476000
2000
網狀球頂
08:16
they're called "buckyballs."
172
478000
2000
他們叫作巴克球
08:18
This evidence was used to suggest
173
480000
2000
這證據通常指出
08:20
that at the end of the Permian, 250 million years ago, a comet hit us.
174
482000
4000
在二疊紀的後期,2500萬年, 一顆彗星打中地球
08:24
And when the comet hits, the pressure produces the buckyballs,
175
486000
3000
當彗星撞擊地球,壓力產生巴克球
08:27
and it captures bits of the comet.
176
489000
2000
它捉住了少許彗星的尾巴
08:29
Helium-3: very rare on the surface of the Earth, very common in space.
177
491000
4000
氦-3:在地球上很罕有,在太空卻常見
08:34
But is this true?
178
496000
2000
但是否屬實?
08:36
In 1990, working on the K-T extinction for 10 years,
179
498000
4000
1990年,用了十年鑽研K-T 絕種
08:40
I moved to South Africa to begin work twice a year
180
502000
3000
一年兩次我會搬到南非卡魯沙漠
08:43
in the great Karoo desert.
181
505000
2000
工作
08:45
I was so lucky to watch the change of that South Africa
182
507000
3000
我很幸運能看到南非轉變
08:48
into the new South Africa as I went year by year.
183
510000
3000
成一個新的南非因我每年都去
08:51
And I worked on this Permian extinction,
184
513000
2000
我研究二疊紀絕種
08:53
camping by this Boer graveyard for months at a time.
185
515000
3000
在波爾墓地露宿了幾個月
08:56
And the fossils are extraordinary.
186
518000
3000
那裡的化石很特別
08:59
You know, you're gazing upon your very distant ancestors.
187
521000
2000
你知道嗎,你在注視著遙遠的祖先
09:01
These are mammal-like reptiles.
188
523000
2000
他們都是類似哺乳動物的爬蟲
09:03
They are culturally invisible. We do not make movies about these.
189
525000
3000
他們的文化已消失了, 所以我們不能拍有關他們的電影
09:06
This is a Gorgonopsian, or a Gorgon.
190
528000
2000
這是Gorgonopsian (一種爬行動物),也叫Gorgon
09:08
That's an 18-inch long skull of an animal
191
530000
4000
這是一隻動物18寸長的頭骨
09:12
that was probably seven or eight feet, sprawled like a lizard,
192
534000
4000
大概7-8尺, 四肢爬起來像一隻蜥蜴
09:16
probably had a head like a lion.
193
538000
2000
大概頭像獅子
09:18
This is the top carnivore, the T-Rex of its time.
194
540000
2000
這是頂級食肉動物, 在那時期是T-Rex
09:20
But there's lots of stuff.
195
542000
2000
但還有很多東西
09:22
This is my poor son, Patrick.
196
544000
2000
這是我可憐的兒子 Patrick
09:24
(Laughter)
197
546000
1000
(眾笑)
09:25
This is called paleontological child abuse.
198
547000
3000
這叫作古生物式的兒童虐待
09:28
Hold still, you're the scale.
199
550000
2000
別動, 你要作標準尺
09:30
(Laughter)
200
552000
5000
(眾笑)
09:36
There was big stuff back then.
201
558000
3000
後面還有很多
09:39
Fifty-five species of mammal-like reptiles.
202
561000
3000
55種類似哺乳動物的爬蟲
09:42
The age of mammals had well and truly started
203
564000
3000
哺乳動物時代已經開始
09:45
250 million years ago ...
204
567000
2000
由2500萬年前開始
09:47
... and then a catastrophe happened.
205
569000
3000
然後有一個災難發生
09:50
And what happens next is the age of dinosaurs.
206
572000
2000
接著是恐龍時代
09:52
It was all a mistake; it should have never happened. But it did.
207
574000
4000
這完全是一個錯失, 事情不應這樣發生,卻發生了
09:56
Now, luckily,
208
578000
2000
幸運地
09:58
this Thrinaxodon, the size of a robin egg here:
209
580000
3000
這蛇頸龍,羅賓蛋的體積
10:01
this is a skull I've discovered just before taking this picture --
210
583000
3000
在拍照前我發現這骸骨
10:04
there's a pen for scale; it's really tiny --
211
586000
2000
這鉛筆作比較,可見它很細小
10:06
this is in the Lower Triassic, after the mass extinction has finished.
212
588000
4000
這是下三疊統,大滅絕之後結束
10:10
You can see the eye socket and you can see the little teeth in the front.
213
592000
3000
你可以見到眼窩和前面的小牙齒
10:13
If that does not survive, I'm not the thing giving this talk.
214
595000
5000
如果這沒生存過,今天我不會在此分享
10:18
Something else is, because if that doesn't survive, we are not here;
215
600000
4000
另一點是,如果它沒有生存過,我們不會在此
10:22
there are no mammals. It's that close; one species ekes through.
216
604000
4000
這裡不會有哺乳動物, 很近, 一個物種之隔
10:26
Well, can we say anything about the pattern of who survives and who doesn't?
217
608000
3000
那我們可以說有一個模式決定誰生存嗎?
10:29
Here's sort of the end of that 10 years of work.
218
611000
2000
這差不多十年的工作
10:31
The ranges of stuff -- the red line is the mass extinction.
219
613000
3000
還有其他--紅色線代表大滅絕
10:34
But we've got survivors and things that get through,
220
616000
2000
但我們發現有大滅絕的生還者
10:36
and it turns out the things that get through preferentially are cold bloods.
221
618000
4000
其中優先生還都是冷血動物
10:40
Warm-blooded animals take a huge hit at this time.
222
622000
4000
恒溫的動物卻無法生存
10:45
The survivors that do get through
223
627000
2000
能經過大滅絕的生還者
10:47
produce this world of crocodile-like creatures.
224
629000
3000
繁殖了類似鱷魚的生物
10:50
There's no dinosaurs yet; just this slow, saurian, scaly, nasty,
225
632000
4000
未有恐龍,只有這種又慢又蜥蜴狀的又有鱗又惡心的
10:54
swampy place with a couple of tiny mammals hiding in the fringes.
226
636000
5000
沼澤地方有些細小的哺乳動物在邊緣之間躲藏著
10:59
And there they would hide for 160 million years,
227
641000
3000
牠們能躲藏1600萬年
11:02
until liberated by that K-T asteroid.
228
644000
3000
直至K-T小行星幫牠們擺脫約束
11:05
So, if not impact, what?
229
647000
2000
如果不是影響,是什麼?
11:07
And the what, I think, is that we returned, over and over again,
230
649000
4000
我想我們會不斷重複又重複經歷
11:11
to the Pre-Cambrian world, that first microbial age,
231
653000
3000
前寒武紀, 第一個微生物時代
11:14
and the microbes are still out there.
232
656000
2000
微生物還存在
11:16
They hate we animals.
233
658000
2000
它們討厭我們這些動物
11:18
They really want their world back.
234
660000
2000
它們很想要回自己的地方
11:20
And they've tried over and over and over again.
235
662000
4000
而它們也不斷不斷地嘗試
11:24
This suggests to me that life causing these mass extinctions
236
666000
3000
這提起我導致大滅絕的生命
11:27
because it did is inherently anti-Gaian.
237
669000
3000
因這是反生態的固有天性
11:30
This whole Gaia idea, that life makes the world better for itself --
238
672000
5000
這個生態主意,是生命會改變環境使它們更適應
11:35
anybody been on a freeway on a Friday afternoon in Los Angeles
239
677000
4000
有無人星期五下在洛杉磯的高速公路上
11:39
believing in the Gaia theory? No.
240
681000
2000
相信生態主意?沒有
11:41
So, I really suspect there's an alternative,
241
683000
3000
所以我懷疑有另一種可能性
11:44
and that life does actually try to do itself in --
242
686000
2000
生命真的有嘗試自己做
11:46
not consciously, but just because it does.
243
688000
2000
不是有意識地,只是它確實如此
11:48
And here's the weapon, it seems, that it did so over the last 500 million years.
244
690000
4000
這個是武器,好像有5億年歷史
11:52
There are microbes which, through their metabolism,
245
694000
3000
微生物會透過新陳代謝
11:55
produce hydrogen sulfide,
246
697000
2000
生產硫化氫
11:57
and they do so in large amounts.
247
699000
3000
它們能大量生產
12:00
Hydrogen sulfide is very fatal to we humans.
248
702000
3000
硫化氫對人類是致命的
12:03
As small as 200 parts per million will kill you.
249
705000
4000
只需每百萬分之200就可以殺死你
12:09
You only have to go to the Black Sea and a few other places -- some lakes --
250
711000
4000
你只需要去黑海和一些湖
12:13
and get down, and you'll find that the water itself turns purple.
251
715000
4000
然後落水,便會發現水變成紫色
12:17
It turns purple from the presence of numerous microbes
252
719000
3000
因大量的微生物存在而變成紫色
12:20
which have to have sunlight and have to have hydrogen sulfide,
253
722000
3000
但首先需要陽光和硫化氫
12:23
and we can detect their presence today -- we can see them --
254
725000
4000
今天我們仍能察覺它們, 我們能看見它們
12:27
but we can also detect their presence in the past.
255
729000
2000
我們也能察覺以前的它們
12:29
And the last three years have seen
256
731000
2000
前三年
12:31
an enormous breakthrough in a brand-new field.
257
733000
3000
在全新的領域上有一個重大的突破
12:34
I am almost extinct --
258
736000
2000
我差不多絕種
12:36
I'm a paleontologist who collects fossils.
259
738000
2000
我是一個搜集化石的古生物學者
12:38
But the new wave of paleontologists -- my graduate students --
260
740000
3000
但新的古生物學者浪潮, 我已畢業的學生
12:41
collect biomarkers.
261
743000
2000
搜集生物標誌物
12:43
They take the sediment itself, they extract the oil from it,
262
745000
4000
他們拿了沉澱物,把裡面的油提煉出來
12:47
and from that they can produce compounds
263
749000
2000
然後再製成複合物
12:49
which turn out to be very specific to particular microbial groups.
264
751000
4000
這複合物對某些微生物是很特別
12:53
It's because lipids are so tough, they can get preserved in sediment
265
755000
4000
因脂質很硬,能保存在沉澱物中
12:57
and last the hundreds of millions of years necessary,
266
759000
3000
如有需要能保存過千萬年
13:00
and be extracted and tell us who was there.
267
762000
2000
再被我們提煉出來
13:02
And we know who was there. At the end of the Permian,
268
764000
3000
我們知道誰曾在那裡.二疊紀的最後期
13:05
at many of these mass extinction boundaries,
269
767000
2000
有很多類似的大滅絕界限裡
13:07
this is what we find: isorenieratene. It's very specific.
270
769000
4000
找到: isorenieratene (化學物的一種),它很獨特
13:11
It can only occur if the surface of the ocean has no oxygen,
271
773000
4000
它只能出現在沒有氧氣的海洋
13:15
and is totally saturated with hydrogen sulfide --
272
777000
3000
它完全被硫化氫飽和
13:18
enough, for instance, to come out of solution.
273
780000
3000
足夠的份量,例如,便會分解
13:21
This led Lee Kump, and others from Penn State and my group,
274
783000
4000
這是李·孔普, 其他人從賓夕法尼亞州立大學和我那隊
13:25
to propose what I call the Kump Hypothesis:
275
787000
3000
提出我名為孔普假設
13:28
many of the mass extinctions were caused by lowering oxygen,
276
790000
3000
很多大滅絕都是因氧氣含量下降
13:31
by high CO2. And the worst effect of global warming, it turns out:
277
793000
4000
二氧化碳含量上升.最慘是全球暖化導致:
13:35
hydrogen sulfide being produced out of the oceans.
278
797000
3000
硫化氫不斷在海洋裡產生
13:38
Well, what's the source of this?
279
800000
2000
源頭在那裡?
13:40
In this particular case, the source over and over has been flood basalts.
280
802000
4000
這事的源頭都是洪水玄武岩
13:44
This is a view of the Earth now, if we extract a lot of it.
281
806000
3000
這是地球,如果我們提取從地球很多
13:47
And each of these looks like a hydrogen bomb;
282
809000
2000
每個都像氫氣炸彈
13:49
actually, the effects are even worse.
283
811000
2000
其實,影響更加差
13:51
This is when deep-Earth material comes to the surface,
284
813000
3000
因當地球深層的物質移到表層
13:54
spreads out over the surface of the planet.
285
816000
2000
就能廣散到行星的表面
13:56
Well, it's not the lava that kills anything,
286
818000
3000
不是熔岩殺死生物
13:59
it's the carbon dioxide that comes out with it.
287
821000
2000
而是從熔岩出來的二氧化碳
14:01
This isn't Volvos; this is volcanoes.
288
823000
3000
這是火山
14:04
But carbon dioxide is carbon dioxide.
289
826000
2000
二氧化碳怎樣也是二氧化碳
14:07
So, these are new data Rob Berner and I -- from Yale -- put together,
290
829000
3000
這些新數據是我和Rob Berner 從耶魯裡放在一起
14:10
and what we try to do now is
291
832000
2000
現在我們試著
14:12
track the amount of carbon dioxide in the entire rock record --
292
834000
3000
記錄二氧化碳在全部石頭裡的含量
14:15
and we can do this from a variety of means --
293
837000
3000
我們可以用不同的方法
14:18
and put all the red lines here,
294
840000
2000
把紅色的線放在一起
14:20
when these -- what I call greenhouse mass extinctions -- took place.
295
842000
3000
這就是我說溫室大滅絕發生的時刻
14:23
And there's two things that are really evident here to me,
296
845000
2000
有兩樣對我來說是很可信的證據
14:25
is that these extinctions take place when CO2 is going up.
297
847000
3000
一是這絕種發生在二氧化碳含量上升時
14:28
But the second thing that's not shown on here:
298
850000
3000
第二樣未能在這裡顯示:
14:31
the Earth has never had any ice on it
299
853000
3000
地球上完全沒有冰
14:34
when we've had 1,000 parts per million CO2.
300
856000
4000
當有每百萬分之1000的二氧化碳
14:38
We are at 380 and climbing.
301
860000
2000
我們現在在380的水平,水平在上升
14:40
We should be up to a thousand in three centuries at the most,
302
862000
3000
我們在三個世紀便能升到1000的水平
14:43
but my friend David Battisti in Seattle says he thinks a 100 years.
303
865000
4000
但我在西雅圖的朋友David Battisti 認為只需100年
14:47
So, there goes the ice caps,
304
869000
2000
接著是冰冠
14:49
and there comes 240 feet of sea level rise.
305
871000
4000
如果水平線上升240呎
14:53
I live in a view house now;
306
875000
2000
我的屋外有境觀
14:55
I'm going to have waterfront.
307
877000
2000
我將會看到海旁區
14:57
All right, what's the consequence? The oceans probably turn purple.
308
879000
4000
好,但結果是?海洋會變成紫色
15:01
And we think this is the reason that complexity took so long
309
883000
3000
我們以為這原因太複雜需要
15:04
to take place on planet Earth.
310
886000
2000
很長時間才會在地球上發生
15:06
We had these hydrogen sulfide oceans for a very great long period.
311
888000
3000
我們有這些硫化氫的海洋已經很長時間
15:09
They stop complex life from existing.
312
891000
4000
它們讓複雜的生命不再存在
15:13
We know hydrogen sulfide is erupting presently a few places on the planet.
313
895000
5000
我們知道硫化氫正在侵蝕地球幾處地方
15:18
And I throw this slide in -- this is me, actually, two months ago --
314
900000
4000
我插入這投影片--這是兩個月前的我--
15:22
and I throw this slide in because here is my favorite animal, chambered nautilus.
315
904000
4000
我放這投影片因是有我最喜歡的動物,鸚鵡螺
15:26
It's been on this planet since the animals first started -- 500 million years.
316
908000
4000
它從5億年前就在在行星上
15:30
This is a tracking experiment, and any of you scuba divers,
317
912000
3000
這是一個追蹤實驗, 有無人是潛水員
15:33
if you want to get involved in one of the coolest projects ever,
318
915000
3000
如因你想參與最酷的計劃
15:36
this is off the Great Barrier Reef.
319
918000
2000
你就要到大堡礁
15:38
And as we speak now,
320
920000
1000
當我們在聊天
15:39
these nautilus are tracking out their behaviors to us.
321
921000
3000
我們也在追蹤鸚鵡螺的行為
15:42
But the thing about this is that every once in a while
322
924000
4000
但是每隔一段時間
15:46
we divers can run into trouble,
323
928000
2000
潛水員便會遇到麻煩
15:48
so I'm going to do a little thought experiment here.
324
930000
2000
所以我想現在做一些思想性實驗
15:50
This is a Great White Shark that ate some of my traps.
325
932000
3000
這是一條大白鯊吃掉我的魚餌
15:53
We pulled it up; up it comes. So, it's out there with me at night.
326
935000
3000
我們拉它上來,它便來,到晚上便與我一起
15:56
So, I'm swimming along, and it takes off my leg.
327
938000
3000
我在游泳,它咬掉我的腿
15:59
I'm 80 miles from shore, what's going to happen to me?
328
941000
3000
我離岸80哩,我可以怎樣做?
16:02
Well now, I die.
329
944000
2000
這樣的話我死定了
16:04
Five years from now, this is what I hope happens to me:
330
946000
2000
五年後, 我希望會發生在我身上:
16:06
I'm taken back to the boat, I'm given a gas mask:
331
948000
3000
我被帶回船上, 有人給我面罩
16:09
80 parts per million hydrogen sulfide.
332
951000
3000
千萬分之80的硫化氫
16:12
I'm then thrown in an ice pond, I'm cooled 15 degrees lower
333
954000
4000
我被丟到冰湖,我的體溫降了15度
16:16
and I could be taken to a critical care hospital.
334
958000
4000
我應該被帶到特級護理的醫院
16:20
And the reason I could do that is because we mammals
335
962000
2000
我能這樣做是因我們哺乳動物
16:22
have gone through a series of these hydrogen sulfide events,
336
964000
3000
已經經歷過一連串硫化氫的事件
16:25
and our bodies have adapted.
337
967000
2000
我們的身體已經適應
16:27
And we can now use this as what I think will be a major medical breakthrough.
338
969000
4000
這例子我認為可作為醫學上的大突破
16:31
This is Mark Roth. He was funded by DARPA.
339
973000
2000
他是Mark Roth,受DARPA贊助
16:33
Tried to figure out how to save Americans after battlefield injuries.
340
975000
4000
想辦法救受戰傷的美國人
16:37
He bleeds out pigs.
341
979000
2000
他幫豬放血
16:39
He puts in 80 parts per million hydrogen sulfide --
342
981000
3000
再灌入千萬分之八十的硫化氫--
16:42
the same stuff that survived these past mass extinctions --
343
984000
3000
就是與以前大滅絕生還的東西一樣--
16:45
and he turns a mammal into a reptile.
344
987000
2000
他由哺乳動物變成爬蟲類
16:47
"I believe we are seeing in this response the result of mammals and reptiles
345
989000
4000
"我相信這反應是哺乳動物和爬蟲類
16:51
having undergone a series of exposures to H2S."
346
993000
3000
經過一連串在H2S暴露的結果"
16:54
I got this email from him two years ago;
347
996000
2000
我兩年前收到他的電郵
16:56
he said, "I think I've got an answer to some of your questions."
348
998000
3000
他說"我想你的問題我有了答案"
16:59
So, he now has taken mice down
349
1001000
2000
所以他現在用老鼠作實驗
17:01
for as many as four hours, sometimes six hours,
350
1003000
4000
一試就4小時,有時甚至6小時
17:05
and these are brand-new data he sent me on the way over here.
351
1007000
2000
於是有全新數據傳送給我
17:07
On the top, now, that is a temperature record of a mouse who has gone through --
352
1009000
5000
最上面,是一隻老鼠的溫度記錄,經過
17:12
the dotted line, the temperatures.
353
1014000
2000
虛線,溫度
17:14
So, the temperature starts at 25 centigrade,
354
1016000
2000
溫度由攝氏25度開始
17:16
and down it goes, down it goes.
355
1018000
1000
不斷下降
17:17
Six hours later, up goes the temperature.
356
1019000
2000
6小時後,溫度上升
17:19
Now, the same mouse is given 80 parts per million hydrogen sulfide
357
1021000
5000
同一隻老鼠現在給牠千萬分之八十的硫化氫
17:24
in this solid graph,
358
1026000
2000
在這固體圖
17:26
and look what happens to its temperature.
359
1028000
2000
看溫度的轉變
17:28
Its temperature drops.
360
1030000
2000
牠的體溫下降
17:30
It goes down to 15 degrees centigrade from 35,
361
1032000
4000
由35度下降到15度
17:34
and comes out of this perfectly fine.
362
1036000
3000
但完全無事
17:37
Here is a way we can get people to critical care.
363
1039000
3000
這就是我們帶人到特級護理
17:40
Here's how we can bring people cold enough to last till we get critical care.
364
1042000
5000
這也是如何使人凍到要帶入特級護理的時候
17:46
Now, you're all thinking, yeah, what about the brain tissue?
365
1048000
4000
你們全在想,對,那腦細胞呢?
17:50
And so this is one of the great challenges that is going to happen.
366
1052000
3000
這是最富挑戰性
17:53
You're in an accident. You've got two choices:
367
1055000
2000
你在一個意外. 你有兩個選擇:
17:55
you're going to die, or you're going to take the hydrogen sulfide
368
1057000
3000
你就快死或你就快要吸入硫化氫
17:58
and, say, 75 percent of you is saved, mentally.
369
1060000
3000
當中75%生還,只是精神上
18:01
What are you going to do?
370
1063000
2000
那你怎樣辦?
18:03
Do we all have to have a little button saying, Let me die?
371
1065000
3000
那我們可能要有個按鈕說:讓我死?
18:06
This is coming towards us,
372
1068000
2000
這正朝著我們
18:08
and I think this is going to be a revolution.
373
1070000
2000
我想這會是一塲革命
18:10
We're going to save lives, but there's going to be a cost to it.
374
1072000
3000
我們要拯救生命,但這是在代價的
18:13
The new view of mass extinctions is, yes, we were hit,
375
1075000
2000
這是大滅絕的一個新觀點,對,我們被撞中
18:15
and, yes, we have to think about the long term,
376
1077000
2000
對,我們要向長遠方向想
18:17
because we will get hit again.
377
1079000
2000
因我們可能再被撞中
18:19
But there's a far worse danger confronting us.
378
1081000
2000
但我們面對著更危險的事
18:21
We can easily go back to the hydrogen sulfide world.
379
1083000
3000
我們很容易回到硫化氫的世界
18:24
Give us a few millennia --
380
1086000
2000
給我們幾千年 -
18:26
and we humans should last those few millennia --
381
1088000
2000
我們人類應該可活多幾千年 --
18:28
will it happen again? If we continue, it'll happen again.
382
1090000
4000
會再發生嗎?如果我們繼續,它會再次發生
18:32
How many of us flew here?
383
1094000
2000
有多少人在這裡?
18:34
How many of us have gone through
384
1096000
2000
在這有多少人經歷迥
18:36
our entire Kyoto quota
385
1098000
3000
整過京都配額
18:39
just for flying this year?
386
1101000
2000
只是今年飛行?
18:41
How many of you have exceeded it? Yeah, I've certainly exceeded it.
387
1103000
3000
有多少人已經超過? 我就一定已經超過
18:44
We have a huge problem facing us as a species.
388
1106000
3000
我們作為一個物種正面對很大的難題
18:47
We have to beat this.
389
1109000
2000
我們要擊敗它
18:49
I want to be able to go back to this reef. Thank you.
390
1111000
4000
我希望能夠回到這珊瑚礁. 多謝
18:53
(Applause)
391
1115000
6000
(掌聲)
18:59
Chris Anderson: I've just got one question for you, Peter.
392
1121000
2000
克里斯安德森 (CA): 我有條問題給你,彼得
19:01
Am I understanding you right, that what you're saying here
393
1123000
2000
我是否理解正確,你是說
19:03
is that we have in our own bodies
394
1125000
2000
我們體內
19:05
a biochemical response to hydrogen sulfide
395
1127000
4000
對硫化氫有生化反應
19:09
that in your mind proves that there have been past mass extinctions
396
1131000
3000
你的思想證明以前的大滅絕
19:12
due to climate change?
397
1134000
2000
都是因氣候變化而形成?
19:14
Peter Ward: Yeah, every single cell in us
398
1136000
2000
彼得沃德(PW):對，我們每個細胞
19:16
can produce minute quantities of hydrogen sulfide in great crises.
399
1138000
3000
在遇到大危機時都能產生一定數量的硫化氫
19:20
This is what Roth has found out.
400
1142000
1000
這是羅斯所找到的
19:21
So, what we're looking at now: does it leave a signal?
401
1143000
2000
所以現在我們要探究：它有無剩下一個？
19:23
Does it leave a signal in bone or in plant?
402
1145000
2000
它有無剩下一個在骨頭裡或植物裡?
19:25
And we go back to the fossil record and we could try to detect
403
1147000
3000
當我們看化石報告,我們嘗試偵測
19:28
how many of these have happened in the past.
404
1150000
2000
有多少發生在在以前
19:30
CA: It's simultaneously
405
1152000
2000
CA: 同時
19:32
an incredible medical technique, but also a terrifying ...
406
1154000
3000
這是令人難以置信的醫學技術,卻又好可怕
19:35
PW: Blessing and curse.
407
1157000
3000
PW: 是福又是禍
ABOUT THE SPEAKER
Peter Ward - PaleontologistPeter D. Ward studies life on Earth -- where it came from, how it might end, and how utterly rare it might be.
Why you should listen
Paleontologist and astrobiologist Peter D. Ward studies the Cretaceous-Tertiary extinction event (the one that killed the dinosaurs) and other mass extinctions. He is a leader in the intriguing new field of astrobiology, the study of the origin, distribution and evolution of life in the universe.
In his book Rare Earth he theorizes that complex life itself is so rare, it's quite possible that Earth is the only planet that has any. But, he theorizes, simple life may exist elsewhere -- and possibly be more common than we think.
His upcoming book, The Medea Hypothesis, makes a bold argument that even here on Earth, life has come close to being wiped out several times. Contrary to the "Gaia hypothesis" of a self-balancing, self-perpetuating circle of life, Ward's Medea hypothesis details the scary number of times that life has come close to flatlining, whether due to comet strikes or an overabundance of bacteria.
In March 2009, Ward's 8-hour television series, Animal Armageddon, premieres on Animal Planet Network.
In April 2013, Ward published a surprisingly moving essay about his life's obsession: the chambered nautilus >>
Peter Ward | Speaker | TED.com