1
00:00:09,300 --> 00:00:12,800
在恐龙时代之前数百万年
Millions of years before the age of dinosaurs...

2
00:00:15,140 --> 00:00:19,720
我们的星球被同样神奇的巨兽统治着
our planet was ruled by equally magnificent beasts.

3
00:00:28,020 --> 00:00:31,110
两个伟大的王朝已经崛起
Two great dynasties had emerged

4
00:00:31,820 --> 00:00:34,490
并在争夺统治权
and were vying for domination.

5
00:00:37,410 --> 00:00:42,950
本集将讲述陆地征服之战
This is the story of the battle to conquer land...

6
00:00:45,210 --> 00:00:50,630
以及它如何彻底改变地球上的一切
and how it changed everything for life on our planet.

7
00:01:51,480 --> 00:01:56,110
《我们星球上的生命》

9
00:01:57,820 --> 00:02:03,410
第 3 章：入侵大地

10
00:02:06,500 --> 00:02:12,750
（5亿年前）

11
00:02:13,590 --> 00:02:15,760
在我们星球的大部分历史中
For most of our planet's history,

12
00:02:16,630 --> 00:02:18,970
陆地都不适于生命居住
land has been inhospitable to life.

13
00:02:23,140 --> 00:02:25,560
一片荒芜
A bleak and desolate realm...

14
00:02:33,900 --> 00:02:36,360
更像是月球表面
more like the surface of the moon...

15
00:02:39,070 --> 00:02:40,610
而不像今天的地球
than like Earth today.

16
00:02:47,040 --> 00:02:49,460
很难想象
It's hard to imagine

17
00:02:49,540 --> 00:02:54,630
任何生命 会在如此充满敌意的地方定居
how anything could ever make this hostile place its home.

18
00:03:02,680 --> 00:03:04,800
但是在海浪之下
But from beneath the waves,

19
00:03:04,890 --> 00:03:08,560
生命已在这里繁荣超过10亿年
where life had thrived for more than a billion years,

20
00:03:10,230 --> 00:03:15,360
有一种好奇的生物率先发出挑战
one curious life-form was among the first to rise to the challenge.

21
00:03:18,650 --> 00:03:20,990
地衣看似不起眼
Lichen may not look remarkable,

22
00:03:21,910 --> 00:03:25,330
但它们其实独一无二
but they are in fact completely unique.

23
00:03:26,530 --> 00:03:28,750
这是一种开创性的合作关系
A pioneering partnership.

24
00:03:34,130 --> 00:03:36,630
地衣既不是植物 也不是动物
Neither plant nor animal,

25
00:03:37,420 --> 00:03:42,760
而是真菌和藻类的奇怪组合
lichen are a strange combination of fungi and algae...

26
00:03:45,800 --> 00:03:47,810
只有在一起
that only together

27
00:03:47,890 --> 00:03:52,980
才能克服贫瘠地球的极度险恶
had what it took to overcome the extreme hostility of barren Earth.

28
00:04:07,120 --> 00:04:10,500
但它们不仅具有开创性
But they were more than just pioneering.

29
00:04:11,790 --> 00:04:13,620
还具有开地性
They were groundbreaking.

30
00:04:21,130 --> 00:04:22,380
随着它们的传播
As they spread...

31
00:04:24,840 --> 00:04:28,260
它们的细丝帮助将岩石分解
...their tiny filaments helped to break down rock

32
00:04:29,260 --> 00:04:32,270
产生了史上第一块土壤
and produce the first ever soil...

33
00:04:35,980 --> 00:04:39,190
为植物的到来铺平道路
paving the way for plants to take over.

34
00:04:42,490 --> 00:04:46,950
苔藓这样的微型植物率先出现
Micro plants, like moss, were first to appear.

35
00:04:50,030 --> 00:04:52,540
叶子只有一层细胞
With leaves only one cell thick,

36
00:04:53,120 --> 00:04:55,370
它们无法向上生长
they couldn't grow upwards,

37
00:04:55,460 --> 00:04:57,500
但可以蔓延开来
but could spread out.

38
00:05:01,500 --> 00:05:04,130
它们的繁殖速度比地衣快
Reproducing faster than lichen,

39
00:05:04,220 --> 00:05:06,510
很快就铺满陆地
they soon carpeted the land,

40
00:05:06,590 --> 00:05:12,520
在之后的4000万年 不受滋扰地统治着陆地
which they ruled undisturbed for the next 40 million years.

41
00:05:26,990 --> 00:05:29,200
但是一场绿色革命即将到来
But a green revolution was coming...

42
00:05:32,660 --> 00:05:35,830
将永远改变陆地的样貌
that would change the landscape forever.

43
00:05:39,290 --> 00:05:42,800
其关键是一种新化合物的进化
Key was the evolution of a new compound,

44
00:05:43,800 --> 00:05:44,800
木质素
lignin.

45
00:05:47,220 --> 00:05:50,890
木质素加强了植物的细胞壁
Lignin strengthened the plants' cell walls...

46
00:05:53,010 --> 00:05:58,560
使植物能够生长得比以往任何时候 都更大、更强壮
allowing them to grow bigger and stronger than ever before.

47
00:06:08,400 --> 00:06:11,620
不再局限于覆盖地面
No longer confined to carpeting the land,

48
00:06:12,530 --> 00:06:16,120
植物开始争夺向上的空间
plants began to battle for the real estate above,

49
00:06:16,870 --> 00:06:20,380
以获取阳光
fighting for access to light.

50
00:06:27,920 --> 00:06:32,180
最终有一些植物长得非常高
Eventually, some plants grew so tall,

51
00:06:32,260 --> 00:06:35,310
从周围的世界中高耸出来
they towered above the world around them.

52
00:06:45,020 --> 00:06:49,030
今天的红杉是大自然的摩天大厦
Today's redwoods are nature's skyscrapers.

53
00:06:54,620 --> 00:06:57,370
高度超过100米
Reaching heights of more than a hundred meters,

54
00:06:58,660 --> 00:07:03,420
是史上最高的生物
they are the tallest living things to have ever existed.

55
00:07:11,130 --> 00:07:17,810
但是红杉只是40万植物物种中的一个
But redwoods are just one of more than 400,000 species of plant,

56
00:07:19,520 --> 00:07:23,270
植物 是我们星球上的生命最鲜明的标志
the most visible signs of life on our planet.

57
00:07:30,950 --> 00:07:32,990
在地球遥远的过去
Back in Earth's distant past,

58
00:07:33,070 --> 00:07:34,740
植物的到来
the arrival of plants

59
00:07:35,320 --> 00:07:39,830
为来自海洋的下一批入侵者 创造了新的栖息地
created new habitats for the next invaders from the sea.

60
00:07:39,910 --> 00:07:44,750
（3.45亿年前）

61
00:07:46,790 --> 00:07:52,720
率先踏上陆地的动物是节肢动物
The first animals to ever set foot on land were the arthropods.

62
00:07:56,760 --> 00:07:58,470
它们是三叶虫的亲戚
Relatives of the trilobites,

63
00:08:00,100 --> 00:08:04,940
坚硬的外骨骼在水下是有用的护甲
their hard exoskeletons had served as useful armor underwater.

64
00:08:11,990 --> 00:08:14,990
在陆地上 这护甲支撑着它们
On land, that armor supported them

65
00:08:15,990 --> 00:08:18,080
并防止水分流失
and prevented them from drying out.

66
00:08:23,750 --> 00:08:27,590
它们也可以通过这坚硬的外壳呼吸
They could also breathe through this tough exterior.

67
00:08:32,380 --> 00:08:36,590
当时的氧气水平比今天高60%
And with oxygen levels 60% higher than they are today,

68
00:08:38,100 --> 00:08:40,520
有一些节肢动物长得异常巨大
some grew to be giants.

69
00:08:53,650 --> 00:08:54,820
节胸蜈蚣
Arthropleura,

70
00:08:55,490 --> 00:08:59,700
地球历史上最大的千足虫
the largest millipede to ever walk the Earth.

71
00:09:05,460 --> 00:09:10,210
长度超过2.5米 宽度超过半米
At over two and a half meters long and a half meter wide,

72
00:09:11,130 --> 00:09:13,340
没有天敌
he has no natural enemies...

73
00:09:17,510 --> 00:09:22,720
所以可以把全部精力放在觅偶上
...so can focus all his energy on finding a mate.

74
00:09:26,390 --> 00:09:28,020
但是对节胸蜈蚣来说
But for Arthropleura,

75
00:09:28,850 --> 00:09:34,070
寻找一位完美的伴侣并不简单
the pursuit of the perfect partner is not straightforward.

76
00:09:37,360 --> 00:09:40,490
因为它看不见
For he's virtually blind...

77
00:09:42,450 --> 00:09:47,870
它的世界仅限于它能感知的范围
...and his world extends only as far as he can sense.

78
00:10:08,520 --> 00:10:11,110
蕨类森林广袤无边
The fern forest is vast,

79
00:10:12,150 --> 00:10:15,480
雌性节胸蜈蚣不知在何处
and a female could be anywhere.

80
00:10:23,080 --> 00:10:26,370
但它的搜寻并不是那么毫无希望
But his search isn't as hopeless as it might seem.

81
00:10:30,080 --> 00:10:33,840
准备交配的雌性会留下气味痕迹
Females ready to mate leave scent trails

82
00:10:33,920 --> 00:10:35,340
供雄性追踪
for males to follow.

83
00:10:37,880 --> 00:10:40,890
这是黑暗中的一线生机
A lifeline in the darkness.

84
00:10:54,860 --> 00:10:58,400
然而感知雌性曾去过哪里
And yet, sensing where she once was

85
00:10:59,070 --> 00:11:04,030
不同于感知雌性现在在哪里
is not the same as sensing where she is.

86
00:11:51,410 --> 00:11:56,000
它施展魅力的机会终于到来
Finally, his chance to charm can begin.

87
00:12:00,460 --> 00:12:06,220
通过自身甲壳间的摩擦 它唱出了独一无二的情歌
By rubbing together parts of his shell, he creates his own unique love song.

88
00:12:34,080 --> 00:12:37,380
在陆地上交配有时是一件尴尬的事
Mating on land can be an awkward affair.

89
00:12:38,790 --> 00:12:42,130
交配成功需要完美的配合
Success requires the perfect alignment.

90
00:12:44,880 --> 00:12:49,050
所以在这关键的时刻
So it's important at this critical stage

91
00:12:49,760 --> 00:12:52,890
不容踏错半步
not to put a foot wrong.

92
00:13:09,580 --> 00:13:12,830
3.45亿年之后
345 million years later,

93
00:13:12,910 --> 00:13:15,500
在今天的森林中
and in today's forests,

94
00:13:15,580 --> 00:13:20,670
节肢动物的求爱艺术有了长足发展
the arthropod art of seduction has come a long way.

95
00:13:23,300 --> 00:13:27,470
对于一些护甲较少的节肢动物 尤其如此
Especially for some of the less armored members of the group.

96
00:13:36,020 --> 00:13:38,600
与古代节胸蜈蚣不同
Unlike the ancient Arthropleura,

97
00:13:40,150 --> 00:13:43,900
雄性跳蛛视力超常
male jumping spiders have superb vision

98
00:13:45,650 --> 00:13:48,950
而且只有一粒米那么大
and are no larger than a grain of rice.

99
00:13:53,490 --> 00:13:55,080
体型上的不足
But what they lack in stature...

100
00:13:59,750 --> 00:14:02,420
它们在风格上弥补
they make up for in style.

101
00:14:06,800 --> 00:14:10,890
每个物种都有自己独特的舞蹈动作
Each species has its own signature dance move

102
00:14:11,550 --> 00:14:13,390
来吸引雌性的注意
to attract female attention.

103
00:14:18,980 --> 00:14:20,020
孔雀开屏
The peacock.

104
00:14:22,360 --> 00:14:23,610
侧身摇摆
The side shuffle.

105
00:14:25,900 --> 00:14:27,110
迪斯科舞步
The disco dancer.

106
00:14:30,030 --> 00:14:32,660
还有摇动羽毛
And the feather shake.

107
00:14:37,620 --> 00:14:43,090
雄性进化出了 多彩的服装和精美的舞步
While the males evolved colorful costumes and intricate dance moves...

108
00:14:45,960 --> 00:14:50,260
雌性则进化出了挑剔的品味
females developed impeccable taste.

109
00:14:53,680 --> 00:14:56,180
它的侧身摇摆吸引了雌性的注意
His side shuffle has caught her attention.

110
00:15:01,480 --> 00:15:04,110
但它是否有对方所钟情的舞姿呢？
But has he got the moves she's looking for?

111
00:15:07,360 --> 00:15:09,570
只有最好的才行
Only the very best will do.

112
00:15:22,630 --> 00:15:28,340
雌性摇动腹部 表示自己并不满意
Waving her abdomen signals she's not impressed.

113
00:15:34,010 --> 00:15:35,550
它需要小心
He needs to be careful,

114
00:15:35,640 --> 00:15:41,440
因为挑剔的雌性有时会吃掉求爱者
for fussy females sometimes eat their suitors.

115
00:15:56,990 --> 00:15:57,950
尽管如此
Still...

116
00:16:01,620 --> 00:16:04,380
再努力一把也是值得的
...it's worth one more try.

117
00:16:15,890 --> 00:16:18,140
它显然还在自作多情
Clearly, he's not getting the message.

118
00:16:32,610 --> 00:16:34,450
它在爱情方面也许不太幸运
He may be unlucky in love,

119
00:16:35,280 --> 00:16:39,990
但它的节肢动物王朝却运气不错
but his arthropod dynasty has had better luck.

120
00:16:42,410 --> 00:16:46,830
节肢动物 如今已占据所有动物物种的80%以上
They now make up over 80% of all animal species.

121
00:16:50,050 --> 00:16:53,050
节肢动物成功的秘诀
The secret to arthropod success

122
00:16:54,130 --> 00:16:57,180
在于其简单的分节结构
lies in their simple segmented body plan...

123
00:17:02,520 --> 00:17:05,890
这种结构向无数不同方向进化
...which has evolved in countless different directions.

124
00:17:14,150 --> 00:17:16,200
有的在腿上有眼睛
Some have ears in their legs.

125
00:17:18,910 --> 00:17:21,830
有的眼睛长在杆子上
Others, eyes on stalks.

126
00:17:24,910 --> 00:17:28,250
还有后备护甲板
And armor plating for battle.

127
00:17:31,670 --> 00:17:34,590
不断变异
Variation after variation,

128
00:17:36,130 --> 00:17:39,090
节肢动物的进化
arthropods are evolution

129
00:17:40,390 --> 00:17:41,560
放纵不羁
run wild.

130
00:17:44,140 --> 00:17:48,690
包括其中最出色的奔跑者
Including the greatest runner of them all,

131
00:17:49,480 --> 00:17:51,070
虎甲
the tiger beetle.

132
00:17:53,780 --> 00:17:58,070
它的设计经过了数百万年的精心调整
Its design has been fine-tuned over millions of years.

133
00:18:00,240 --> 00:18:04,040
最新版本为速度而生
The latest model is built for speed.

134
00:18:13,920 --> 00:18:18,840
就其体积而言 它是地球上最快的短跑运动员之一
For its size, it is one of the fastest sprinters on Earth.

135
00:18:22,390 --> 00:18:24,600
如果按照人类的比例放大
If scaled up to human proportions,

136
00:18:26,480 --> 00:18:27,810
它的奔跑速度
it would run

137
00:18:28,770 --> 00:18:32,270
超过每小时1000公里
at over 1,000 kilometers per hour.

138
00:18:34,730 --> 00:18:37,950
但是快车道上的生活也有一个缺点
But there is one drawback to life in the fast lane.

139
00:18:41,160 --> 00:18:43,780
它的大脑跟不上
His brain can't keep up.

140
00:18:45,740 --> 00:18:49,870
在追逐猎物的过程中
He must frequently stop to get his bearings

141
00:18:51,250 --> 00:18:55,090
它必须经常停下来确认方向
while hunting down his next victim.

142
00:19:06,430 --> 00:19:11,350
但它对食物的疯狂搜寻 也可能让它陷入危险境地
But his frantic search for food can lead him into dangerous territory...

143
00:19:14,820 --> 00:19:21,820
因为有时候猎手也会成为猎物
because sometimes the hunter can also be the hunted.

144
00:19:31,710 --> 00:19:36,340
速度与激情不是这种活板门蛛的风格
Fast and furious is not this trapdoor spider's style.

145
00:19:39,460 --> 00:19:44,220
它更喜欢等待猎物靠近
She prefers to wait for prey to come to her.

146
00:20:47,620 --> 00:20:49,870
在节肢动物的争斗中
In the battle of the arthropods,

147
00:20:50,410 --> 00:20:54,960
飞行往往能决定生死
flight would often make the difference between life and death.

148
00:21:00,960 --> 00:21:03,630
3亿多年前
More than 300 million years ago,

149
00:21:04,300 --> 00:21:06,800
一群节肢动物
one group of arthropods

150
00:21:06,890 --> 00:21:10,810
成为率先上天的生物
were the first creatures to take to the skies.

151
00:21:17,600 --> 00:21:19,520
翅膀的进化
And the evolution of wings

152
00:21:20,940 --> 00:21:24,070
最终将使它们在全球范围内取得成功
would eventually launch them to global success.

153
00:21:27,860 --> 00:21:29,450
昆虫
The insects.

154
00:21:36,040 --> 00:21:39,500
今天地球上的昆虫
Today, for every human on the planet,

155
00:21:39,580 --> 00:21:42,880
超过人类数量的10亿倍
there are more than a billion insects.

156
00:21:46,760 --> 00:21:50,890
它们是地球上数量最多的动物
They are the most abundant group of animals on Earth.

157
00:21:57,690 --> 00:22:02,570
（3.1亿年前）

158
00:22:07,780 --> 00:22:10,200
尽管它们如今非常成功
Despite their current success,

159
00:22:10,950 --> 00:22:15,950
最终能够飞行的昆虫 最早出现在古代沼泽中
the ultimate flying insects first appeared back in the ancient swamps.

160
00:22:18,670 --> 00:22:20,290
蜻蜓
Dragonflies.

161
00:22:24,460 --> 00:22:28,300
它们的飞行几乎堪称完美
Their flight is as close to perfect as it gets.

162
00:22:31,640 --> 00:22:33,510
四片灵活的翅膀
Four flexible wings,

163
00:22:34,100 --> 00:22:36,270
可以独立控制
independently controlled,

164
00:22:36,350 --> 00:22:39,060
使它们拥有无与伦比的机动性
give them unparalleled mobility.

165
00:22:41,560 --> 00:22:45,230
它们可以朝任何方向飞行
They can fly in any direction,

166
00:22:47,150 --> 00:22:49,280
完成最急的转弯
pull off the tightest turns...

167
00:22:52,820 --> 00:22:56,370
加速比战斗机更快
and accelerate faster than a fighter jet.

168
00:22:59,540 --> 00:23:01,420
如此成功的设计
A winning design

169
00:23:01,500 --> 00:23:07,090
已经保持了数亿年 几乎不变
that has remained almost the same for hundreds of millions of years.

170
00:23:12,590 --> 00:23:16,850
然而在同一片史前沼泽之中
And yet, living in the same prehistoric swamps,

171
00:23:17,470 --> 00:23:22,560
另一群动物正在经历巨变
another group of animals were undergoing their own radical change.

172
00:23:26,820 --> 00:23:28,240
在水面下方
Beneath the surface,

173
00:23:29,240 --> 00:23:32,660
脊椎动物继续进化
vertebrates had continued to evolve...

174
00:23:35,580 --> 00:23:39,580
一种新型鱼类蓬勃发展
and a new type of fish was thriving,

175
00:23:40,660 --> 00:23:42,710
叶鳍鱼
the lobe-finned fish.

176
00:23:52,800 --> 00:23:57,060
有一些长成了巨大而可怕的捕食者
Some grew to be monstrous predators.

177
00:24:06,440 --> 00:24:09,570
在这个鱼吃鱼的世界
In this fish-eat-fish world,

178
00:24:10,570 --> 00:24:12,740
大就是好
it pays to be big.

179
00:24:21,410 --> 00:24:25,380
较小的鱼 可以在浅海寻求庇护
For the smaller ones, there's refuge in the shallows...

180
00:24:29,460 --> 00:24:34,510
在那里 它们独特的叶鳍是一种明显的优势
where their unique lobed fins are a distinct advantage.

181
00:24:37,100 --> 00:24:40,680
它们肌肉发达且随机应变
Muscular and highly versatile,

182
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叶鳍与其他鱼的鳍不同
they are different to those of other fish.

183
00:24:48,060 --> 00:24:50,320
不仅有助于游泳
Not only do they help them swim...

184
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而且足够强壮 能够支撑它们的体重
but they're strong enough to support their body weight...

185
00:25:00,790 --> 00:25:06,210
帮助它们从水中爬出
and help them crawl out of the water.

186
00:25:11,000 --> 00:25:16,050
但这些鱼 还有另一种极为重要的适应性
But these fish also have another game-changing adaptation...

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00:25:18,140 --> 00:25:22,270
呼吸空气的能力
the ability to breathe air.

188
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不是通过腮 而是通过原始的肺呼吸
Not through gills but through primitive lungs.

189
00:25:33,070 --> 00:25:36,990
这些进化一起作用
Together, these evolutionary advances

190
00:25:37,070 --> 00:25:42,240
使脊椎动物能够离开水体并探索陆地
allowed vertebrates to leave the water and explore the land.

191
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争夺新世界的竞赛已经开始
The race was on to colonize this new world.

192
00:25:58,470 --> 00:26:01,140
但对于这些叶鳍鱼来说
But it was already too late

193
00:26:02,640 --> 00:26:04,890
已经太晚了
for these lobe-finned fish.

194
00:26:08,770 --> 00:26:11,730
其他动物先它们一步完成了这种转变
Others had made this transition before them.

195
00:26:27,910 --> 00:26:30,920
比如三米长的石炭鲵
Like the three-meter-long Anthracosaurus...

196
00:26:34,630 --> 00:26:36,970
已经长出腿来
...that had already found its feet.

197
00:26:47,980 --> 00:26:52,480
从鳍到肢的进化用了数百万年
The evolution from fin to limb took millions of years.

198
00:26:57,940 --> 00:26:59,450
但一旦完成
But once completed,

199
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陆地上的生活将永远改变
life on land would never be the same again.

200
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两栖动物的时代
The age of amphibians

201
00:27:21,510 --> 00:27:22,640
已经开始
had begun.

202
00:27:40,900 --> 00:27:47,240
今天有超过8000个两栖动物物种
Today, there are more than 8,000 species of amphibian.

203
00:27:50,540 --> 00:27:53,960
这是一个奇怪却多样的种群
A peculiar but diverse group...

204
00:27:57,670 --> 00:27:58,920
有蝾螈
...of newts,

205
00:27:59,670 --> 00:28:00,840
青蛙
frogs,

206
00:28:01,510 --> 00:28:02,840
火蝾螈
salamanders,

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00:28:03,760 --> 00:28:04,840
还有蟾蜍
and toads.

208
00:28:07,140 --> 00:28:10,100
虽不再是曾经的巨兽
Not quite the giants they once were,

209
00:28:11,020 --> 00:28:13,520
但仍然是成功的猎手
but still successful hunters...

210
00:28:16,520 --> 00:28:19,860
拥有独特的杀手风格
...with their own killer style.

211
00:28:28,910 --> 00:28:32,330
石炭鲵出现之后几亿年
Hundreds of millions of years after Anthracosaurus,

212
00:28:33,460 --> 00:28:37,960
沼泽仍然是两栖动物的根据地
swamplands remain a stronghold for amphibians.

213
00:28:42,130 --> 00:28:45,390
在欧洲的多瑙河三角洲
Here in Europe's Danube delta,

214
00:28:45,470 --> 00:28:48,890
湖侧褶蛙成千上万
marsh frogs live in their thousands

215
00:28:49,680 --> 00:28:53,100
已经成为专业的昆虫猎手
and have become expert insect hunters...

216
00:28:55,690 --> 00:29:00,900
尤其喜欢捕食蜻蜓
with a particular taste for dragonflies.

217
00:29:07,820 --> 00:29:09,950
蜻蜓有全方位视觉
Thanks to their wraparound vision,

218
00:29:12,450 --> 00:29:15,040
要抓住它可不容易
catching one isn't easy.

219
00:29:16,420 --> 00:29:22,550
但是湖侧褶蛙也进化出了 一些奇特的适应性
But marsh frogs have evolved some quirky adaptations of their own.

220
00:29:32,680 --> 00:29:35,730
蹼有助于腾空
Webbed feet help them get airborne.

221
00:29:44,110 --> 00:29:49,030
弹射式的舌头 使它们拥有了超长的射程
And a projectile tongue gives them extraordinary reach.

222
00:29:57,040 --> 00:29:58,250
即便如此
Even so,

223
00:29:58,330 --> 00:30:05,090
飞行中的蜻蜓仍然很难捕获
dragonflies in flight can be just too hard to catch.

224
00:30:10,090 --> 00:30:14,560
等待这些空中杂技演员降落 可能会降低抓捕难度
Waiting for the aerial acrobats to land might make things easier.

225
00:30:53,560 --> 00:30:55,560
是时候换一种方法了
Time to take a different approach.

226
00:31:00,940 --> 00:31:05,150
一只雌性蜻蜓在水上产卵
A female laying eggs in the water.

227
00:31:10,780 --> 00:31:12,490
半浸在水中
Half-submerged,

228
00:31:13,530 --> 00:31:16,160
它应该是一个比较容易对付的目标
she should be an easier target.

229
00:31:44,980 --> 00:31:49,530
但蜻蜓实在太快了
The dragonflies are just too fast.

230
00:32:02,040 --> 00:32:05,210
还会翻滚动作
And they can barrel-roll.

231
00:32:26,610 --> 00:32:27,860
又没抓住
Missed again.

232
00:32:30,570 --> 00:32:35,200
但青蛙生性坚持不懈
But frogs are nothing if not persistent.

233
00:32:50,000 --> 00:32:52,300
虽然命中率低
Despite the low hit rate,

234
00:32:52,380 --> 00:32:58,510
但两栖动物已在地球上生存 超过3.5亿年
amphibians have survived for over 350 million years.

235
00:33:03,020 --> 00:33:08,270
然而它们并未征服 地球上的每一种环境
And yet, they never conquered every environment the planet had to offer...

236
00:33:10,610 --> 00:33:15,820
因为所有两栖动物养育后代 都需要一样东西
because there's something all amphibians need to raise their young.

237
00:33:19,120 --> 00:33:20,120
水
Water.

238
00:33:23,540 --> 00:33:27,210
这是哥斯达黎加的草莓箭毒蛙
This is the strawberry dart frog of Costa Rica.

239
00:33:33,090 --> 00:33:35,970
它的蝌蚪危在旦夕
Her tadpoles are in mortal danger.

240
00:33:38,550 --> 00:33:41,850
小水洼几乎快要干涸
Their tiny puddle, almost dry.

241
00:33:57,450 --> 00:34:00,030
唯一的逃生方法
Their only means of escape

242
00:34:00,950 --> 00:34:03,040
就是爬到母亲的背上
is on their mother's back.

243
00:34:06,370 --> 00:34:09,630
难点在于找到水
The hard part is finding water.

244
00:34:14,170 --> 00:34:15,010
幸运的是
Luckily...

245
00:34:18,930 --> 00:34:21,640
它知道该去哪里
...she knows exactly where to go.

246
00:34:28,310 --> 00:34:29,850
在它上方20米处
Twenty meters above her,

247
00:34:31,400 --> 00:34:33,860
一株凤梨科植物蓄集雨水
a bromeliad collects rainwater.

248
00:34:37,280 --> 00:34:40,700
对它珍贵的蝌蚪来说 是完美的池塘
The perfect pool for her precious tadpole.

249
00:34:43,240 --> 00:34:46,290
但是它首先必须上去
But first, she must get there...

250
00:34:48,750 --> 00:34:51,880
一次跳一步
one hop at a time.

251
00:35:02,010 --> 00:35:05,100
它仅有人类指甲般大小
Barely the size of a human thumbnail,

252
00:35:05,770 --> 00:35:09,100
这对它来说是珠穆朗玛峰
this is her own personal Everest.

253
00:35:36,090 --> 00:35:38,010
终于安全了
Safe at last.

254
00:35:48,020 --> 00:35:52,310
不论两栖动物 在征服陆地的过程中达到如何的高度
No matter what great heights amphibians reached in their conquest of land...

255
00:35:55,440 --> 00:35:58,360
它们永远无法摆脱与水的联系
they never escaped their tie to water...

256
00:36:00,400 --> 00:36:05,280
当地球上的环境剧变时
a tie that would be their undoing when conditions on Earth...

257
00:36:07,330 --> 00:36:09,000
这种联系将使它们毁灭
radically changed.

258
00:36:16,790 --> 00:36:21,630
（3亿年前）

259
00:36:21,720 --> 00:36:24,590
在石炭纪
During the period known as the Carboniferous,

260
00:36:25,390 --> 00:36:28,680
地球各大陆合为一体
Earth's great land masses merged,

261
00:36:28,760 --> 00:36:32,640
超级大陆“盘古大陆”诞生
and the supercontinent of Pangaea was born.

262
00:36:35,440 --> 00:36:37,110
随着陆地变干
As the land dried,

263
00:36:37,940 --> 00:36:40,530
广阔的沼泽开始消失
the vast swamps began to disappear.

264
00:36:43,030 --> 00:36:47,280
由于缺水 多数两栖动物苦苦挣扎
Lacking water, most amphibians struggled.

265
00:36:52,370 --> 00:36:53,660
但并非全部如此
But not all.

266
00:36:55,250 --> 00:36:58,420
有一种两栖动物 进化出了一种革命性的适应性
One evolved a revolutionary adaptation

267
00:36:58,500 --> 00:37:00,670
使其繁荣发展
that enabled it to thrive.

268
00:37:06,470 --> 00:37:10,140
它的卵进化出了一层保护性外壳
Its egg developed a protective shell

269
00:37:10,220 --> 00:37:15,140
将胚胎保护在“私家泳池”之中
that held the embryo in its own private pool of fluid.

270
00:37:18,940 --> 00:37:24,700
幼崽在其中能够安全地发育 而不会干涸
Inside, the young could develop safely without drying out.

271
00:37:38,170 --> 00:37:39,880
由于蛋的进化
The tie to water

272
00:37:39,960 --> 00:37:46,550
与水的联系终于被断开
was finally broken by the evolution of this amniotic egg.

273
00:37:52,810 --> 00:37:55,140
这些羊膜动物
Known as the amniotes,

274
00:37:55,230 --> 00:37:58,650
能够以两栖动物无法做到的方式
these creatures could colonize the drier land

275
00:37:58,730 --> 00:38:01,270
在干旱的土地上繁衍
in a way that amphibians could not.

276
00:38:06,650 --> 00:38:10,660
从这一共同祖先开始
And from this one common ancestor,

277
00:38:10,740 --> 00:38:14,500
所有哺乳动物、爬行动物、鸟类
all mammals, reptiles, birds,

278
00:38:14,580 --> 00:38:18,080
以及恐龙都将发展而来
and dinosaurs would descend.

279
00:38:50,910 --> 00:38:56,040
（2.52亿年前）

280
00:38:57,290 --> 00:39:01,540
进化出蛋之后6000万年
Sixty million years after the evolution of the amniotic egg,

281
00:39:03,130 --> 00:39:06,130
羊膜动物已遍布盘古大陆
amniotes have spread across Pangaea...

282
00:39:10,890 --> 00:39:13,600
形成两个新的王朝
...producing two new dynasties

283
00:39:13,680 --> 00:39:16,810
无尽的竞争也由此开始
and the start of an endless rivalry.

284
00:39:22,810 --> 00:39:28,490
这些沉睡着的身穿护甲的野兽 是一种原始的爬行动物
These sleeping armored beasts are a primitive type of reptile.

285
00:39:35,120 --> 00:39:40,250
盾甲龙是陆地上最大的动物之一
Scutosaurus, among the largest animals on land.

286
00:39:59,600 --> 00:40:01,230
重量超过一吨
Weighing over a ton,

287
00:40:02,980 --> 00:40:06,360
它们地球上最早的巨型食草动物
they are the first giant plant-eaters to roam the planet.

288
00:40:12,320 --> 00:40:16,660
蛋能使它们在干旱的环境下兴旺发展
Amniotic eggs allowed them to flourish in the drier conditions

289
00:40:17,200 --> 00:40:20,000
并前往其他动物去不了的地方
and go where others could not.

290
00:40:24,580 --> 00:40:27,460
但是盘古大陆并不只属于它们
But Pangaea didn't just belong to them.

291
00:40:33,130 --> 00:40:35,890
另一条血脉出现了
Another new bloodline had emerged.

292
00:40:36,890 --> 00:40:39,810
它们是哺乳动物的祖先
The ancestors of the mammals.

293
00:40:47,860 --> 00:40:51,320
水龙兽虽然无法与盾甲龙相匹敌
While a Lystrosaurus is no match for a Scutosaur...

294
00:40:53,650 --> 00:40:56,530
但它的亲戚可以
...he has cousins here who are.

295
00:41:20,760 --> 00:41:22,220
丽齿兽
A gorgonopsid.

296
00:41:25,900 --> 00:41:29,320
它是哺乳动物更为显赫的前身
A more impressive forerunner to the mammals.

297
00:41:33,030 --> 00:41:37,660
身长超过三米 体重超过300千克
At over three meters long and 300 kilos,

298
00:41:38,820 --> 00:41:42,080
它能与如今的任何大型猫科动物 一较高下
she rivals any big cat alive today.

299
00:41:48,580 --> 00:41:50,790
它有强大的嗅觉
With her powerful sense of smell,

300
00:41:51,880 --> 00:41:54,010
追踪猎物对它来说易如反掌
tracking her prey is easy.

301
00:41:56,840 --> 00:41:58,890
但是击穿对方的重甲
Getting past their heavy armor

302
00:42:00,140 --> 00:42:02,140
就没那么容易了
will be her greatest challenge.

303
00:42:08,440 --> 00:42:10,520
但它有一样秘密武器
But she has a secret weapon.

304
00:42:13,440 --> 00:42:15,070
刀刃一般的牙齿
Saber-like teeth.

305
00:42:22,580 --> 00:42:23,580
即便如此
Even so,

306
00:42:24,870 --> 00:42:27,290
它仍需要悄无声息地靠近
she'll need stealth to get close.

307
00:43:06,830 --> 00:43:08,750
它必须非常谨慎
She must choose her moment...

308
00:43:13,210 --> 00:43:14,550
选好时机
and her target

309
00:43:16,380 --> 00:43:17,340
选好目标
carefully.

310
00:43:25,760 --> 00:43:26,810
慢慢地
Slowly

311
00:43:28,390 --> 00:43:29,810
悄无声息地
and silently...

312
00:43:33,190 --> 00:43:34,150
展开行动
does it.

313
00:44:50,430 --> 00:44:53,230
哺乳动物与爬行动物的竞争
The rivalry between mammals and reptiles

314
00:44:54,140 --> 00:44:58,860
数亿年来 一直是地球生命的特点
has been a feature of life on Earth for hundreds of millions of years.

315
00:45:02,190 --> 00:45:05,450
但它们的早期崛起并不会持续太久
But their early rise was not to last,

316
00:45:06,280 --> 00:45:09,910
因为在盘古大陆遥远的北方
because in the far north of Pangaea,

317
00:45:10,660 --> 00:45:13,460
灾难正在发生
something catastrophic was happening.

318
00:45:18,170 --> 00:45:25,180
埋在地球表面之下多年的巨大力量
Lying dormant for years on end, the colossal forces at work beneath Earth's surface

319
00:45:26,140 --> 00:45:28,010
很容易被遗忘
are easily forgotten.

320
00:45:33,390 --> 00:45:35,600
但这地下熔岩世界
But the molten underworld

321
00:45:36,900 --> 00:45:39,190
总在不停搅动
is always stirring,

322
00:45:40,570 --> 00:45:42,900
寻找弱点
always probing for weakness.

323
00:45:52,830 --> 00:45:54,830
在盘古大陆的地壳之下
Beneath Pangaea's crust,

324
00:45:56,120 --> 00:45:58,500
一股极热的岩浆
a plume of superheated magma

325
00:45:59,080 --> 00:46:01,460
正朝着地表前进
was working its way to the surface.

326
00:46:08,680 --> 00:46:11,600
二叠纪的喷发一旦开始
Once these Permian eruptions started...

327
00:46:14,520 --> 00:46:16,560
就无法停止
there was no stopping them.

328
00:46:44,050 --> 00:46:48,430
其特点是规模极大
What made them unique was their monumental scale.

329
00:46:58,640 --> 00:47:00,810
是生命见证过的
They were among the largest,

330
00:47:01,860 --> 00:47:07,030
最大、最猛烈的喷发之一
most violent eruptions that life has ever witnessed.

331
00:47:17,960 --> 00:47:22,040
持续肆虐了10万年
And they raged for 100,000 years.

332
00:47:24,090 --> 00:47:27,460
造成的破坏前所未见
The devastation was unprecedented.

333
00:47:30,300 --> 00:47:33,300
一个面积相当于半个美国的区域
An area half the size of the United States

334
00:47:34,050 --> 00:47:36,100
被熔岩吞噬
lost to lava.

335
00:47:59,000 --> 00:48:01,160
数百万平方公里
Millions of square kilometers,

336
00:48:01,920 --> 00:48:03,920
曾经充满生命
once so full of life,

337
00:48:04,500 --> 00:48:07,920
却被地球自身所毁灭
obliterated by the Earth itself.

338
00:48:17,850 --> 00:48:21,480
而这还只是刚刚开始
And that was just the beginning.

339
00:48:25,270 --> 00:48:30,240
喷发释放出比熔岩更危险的东西
The eruptions released something far more dangerous than lava.

340
00:48:33,910 --> 00:48:38,870
一种有毒的混合气体
A toxic concoction of noxious gases.

341
00:48:50,170 --> 00:48:52,880
当这些气体与水结合时
When these gases combined with water...

342
00:49:00,140 --> 00:49:03,940
威力强大的酸雨倾泻而下
a potent cocktail of acid rain poured down.

343
00:49:13,860 --> 00:49:15,110
水
Water, the giver of life,

344
00:49:15,200 --> 00:49:16,450
生命的赐予者
the giver of life,

345
00:49:17,410 --> 00:49:20,160
如今却成了生命的毁灭者
was now its destroyer.

346
00:49:26,880 --> 00:49:29,960
毒雨毒害大地
The toxic rain poisoned the ground...

347
00:49:32,090 --> 00:49:33,720
灭绝植物
killing off the plants.

348
00:49:41,810 --> 00:49:44,980
没有了根来固定土壤
Without their roots to bind the soil together...

349
00:49:49,150 --> 00:49:52,990
整个生态系统被冲走
entire ecosystems were washed away.

350
00:50:12,960 --> 00:50:19,010
然而空气中 还有一种更具破坏性的东西
And yet, there was something even more destructive in the air.

351
00:50:22,220 --> 00:50:23,640
一位隐形杀手
A silent killer.

352
00:50:26,810 --> 00:50:29,350
二氧化碳
Carbon dioxide.

353
00:50:32,690 --> 00:50:34,860
火山释放出的二氧化碳
The volcanoes released

354
00:50:34,940 --> 00:50:40,410
比我们今天大气中的二氧化碳多六倍
six times more CO2 than is in our atmosphere today...

355
00:50:43,450 --> 00:50:46,910
导致全球气温升高十度
triggering ten degrees of global warming...

356
00:50:50,790 --> 00:50:53,380
各种气候灾难
...and all the climate devastation

357
00:50:54,880 --> 00:50:56,050
随之而来
that comes with it.

358
00:51:09,690 --> 00:51:15,360
温室效应在大自然的力量下肆虐
Hothouse Earth raged as the forces of nature ran wild.

359
00:51:40,800 --> 00:51:43,970
一片混乱 无处可藏
There was nowhere to hide from the chaos.

360
00:51:45,720 --> 00:51:49,100
海洋受到的影响最为严重
And the oceans were worst affected.

361
00:51:51,980 --> 00:51:54,230
随着海洋变暖和酸化
As they warmed and acidified,

362
00:51:55,110 --> 00:51:57,110
氧含量锐减
oxygen levels plummeted...

363
00:51:59,690 --> 00:52:03,780
最早孕育生命的海洋
turning the seas, where life first took hold,

364
00:52:06,030 --> 00:52:08,200
变成了荒芜的坟场
into a desolate graveyard.

365
00:52:11,370 --> 00:52:14,000
这是地球上第三次
This was the planet's third,

366
00:52:14,670 --> 00:52:18,300
也是最具毁灭性的大规模灭绝事件
and most devastating, mass extinction.

367
00:52:20,260 --> 00:52:23,550
90%的物种
Ninety percent of all species

368
00:52:24,470 --> 00:52:26,850
永远消失
lost forever.

369
00:52:33,020 --> 00:52:37,730
进化树的许多分支完全断裂
Entire branches torn off the evolutionary tree.

370
00:52:46,280 --> 00:52:47,740
许多物种灭绝了
But in the loss of many,

371
00:52:48,740 --> 00:52:50,410
但是少数物种幸存下来
endured the few.

372
00:52:58,960 --> 00:53:02,170
它们是一个过去时代的仅存硕果
All that remained of a bygone age.

373
00:53:07,390 --> 00:53:13,060
其生存从未如此重要
Never had their survival been so important.

374
00:53:17,520 --> 00:53:20,480
一切生命的未来
The future of all life

375
00:53:21,570 --> 00:53:24,530
如今都悬于一线
now hung by a thread.

376
00:55:12,050 --> 00:55:14,600
字幕翻译：朱音