Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated:
1
00:00:06,177 --> 00:00:07,762
[thunder rumbles]
2
00:00:10,890 --> 00:00:12,892
[poignant music playing]
3
00:00:16,604 --> 00:00:18,565
[Morgan Freeman] For billions of years,
4
00:00:19,357 --> 00:00:23,153
much of our world
was fiercely inhospitable…
5
00:00:23,236 --> 00:00:25,363
[crackling thunder]
6
00:00:25,447 --> 00:00:29,659
…ravaged by the elements
and the forces of nature.
7
00:00:31,745 --> 00:00:33,246
[howling wind]
8
00:00:34,706 --> 00:00:40,253
But this is the story
of what was happening beneath the waves.
9
00:00:44,299 --> 00:00:49,763
Here, shielded from the storms,
life had taken hold…
10
00:00:49,846 --> 00:00:51,890
[rumbling thunder]
11
00:00:52,515 --> 00:00:57,228
…and was about
to change our planet forever.
12
00:00:57,312 --> 00:00:59,564
[sinister music playing]
13
00:01:10,742 --> 00:01:13,203
[sinister music intensifies]
14
00:01:14,245 --> 00:01:16,247
[music ends]
15
00:01:17,373 --> 00:01:19,375
[rousing music playing]
16
00:01:32,972 --> 00:01:34,682
[low growling]
17
00:01:41,773 --> 00:01:44,192
[snarling]
18
00:01:44,275 --> 00:01:46,361
[trilling]
19
00:01:48,196 --> 00:01:49,447
[screeching]
20
00:01:49,531 --> 00:01:52,534
[rousing music continues]
21
00:02:00,542 --> 00:02:02,544
[growling]
22
00:02:02,627 --> 00:02:04,546
[wind howling]
23
00:02:06,631 --> 00:02:08,633
[rumbling]
24
00:02:10,593 --> 00:02:12,428
[rousing music intensifies]
25
00:02:15,348 --> 00:02:17,350
[music fades]
26
00:02:23,356 --> 00:02:25,358
[ominous music playing]
27
00:02:38,079 --> 00:02:40,373
Far back in the depths of time,
28
00:02:41,040 --> 00:02:44,836
Earth looked nothing
like the world we know today.
29
00:02:50,049 --> 00:02:53,553
Nearly 90% of its surface was water,
30
00:02:54,304 --> 00:02:57,098
yet this was no blue planet.
31
00:03:00,101 --> 00:03:05,857
Instead, vast clouds of methane
had turned the atmosphere yellow.
32
00:03:05,940 --> 00:03:07,942
[thunder rumbles]
33
00:03:09,986 --> 00:03:12,197
[explosive blast]
34
00:03:12,280 --> 00:03:15,158
On land, conditions were even worse.
35
00:03:15,241 --> 00:03:16,701
[repeated blasts]
36
00:03:25,335 --> 00:03:30,381
Volcanoes had been erupting
for millions of years.
37
00:03:30,465 --> 00:03:32,467
[rumbling, creaking]
38
00:03:34,928 --> 00:03:36,596
Their explosive power,
39
00:03:36,679 --> 00:03:41,017
one of the few sounds
in this otherwise silent realm.
40
00:03:41,100 --> 00:03:43,102
[ominous music continues]
41
00:03:51,361 --> 00:03:56,699
With the world made up of nothing
but toxic air and rivers of molten rock…
42
00:03:59,077 --> 00:04:03,039
life as we know it was impossible.
43
00:04:05,166 --> 00:04:07,168
[crackling, hissing]
44
00:04:10,672 --> 00:04:12,674
[stillness]
45
00:04:13,299 --> 00:04:15,677
But out in the prehistoric seas,
46
00:04:16,511 --> 00:04:19,013
something is stirring.
47
00:04:19,097 --> 00:04:21,099
[intriguing music playing]
48
00:04:25,603 --> 00:04:30,525
Beneath the surface
hangs a great swathe of plankton.
49
00:04:37,031 --> 00:04:42,328
Microscopic cells like these
have just evolved something new,
50
00:04:43,955 --> 00:04:45,206
photosynthesis.
51
00:04:50,420 --> 00:04:53,798
This means they can harness
the sun's energy to grow,
52
00:04:55,049 --> 00:04:56,759
a breakthrough so important
53
00:04:58,011 --> 00:05:03,099
that plankton will one day give rise
to every single plant on Earth.
54
00:05:03,182 --> 00:05:05,184
[intriguing music continues]
55
00:05:08,479 --> 00:05:09,981
But that's not all.
56
00:05:11,357 --> 00:05:15,987
One byproduct of photosynthesis is a gas,
57
00:05:17,447 --> 00:05:21,868
the missing ingredient
for animal life to exist…
58
00:05:22,410 --> 00:05:24,495
[rousing music playing]
59
00:05:24,579 --> 00:05:25,580
…oxygen.
60
00:05:30,376 --> 00:05:32,712
For nearly two billion years,
61
00:05:32,795 --> 00:05:38,343
plankton produced so much oxygen
that it transformed our planet.
62
00:05:40,136 --> 00:05:42,138
[stirring music playing]
63
00:05:44,891 --> 00:05:49,354
No longer hostile,
Earth became a new world,
64
00:05:51,230 --> 00:05:54,776
where life could finally run wild.
65
00:05:56,486 --> 00:05:58,571
[music fades]
66
00:05:58,654 --> 00:06:00,740
[wind blowing]
67
00:06:03,451 --> 00:06:06,204
Today, millions of years later,
68
00:06:06,287 --> 00:06:12,418
it's still possible to get a glimpse
of what that next wave of life was like.
69
00:06:18,841 --> 00:06:21,719
Because in some parts of our shallow seas…
70
00:06:24,430 --> 00:06:27,892
life still resembles
that more primitive time.
71
00:06:27,975 --> 00:06:30,978
[whimsical music playing]
72
00:06:37,151 --> 00:06:38,486
They may not look like it…
73
00:06:40,863 --> 00:06:43,032
but these are animals…
74
00:06:47,120 --> 00:06:50,581
very similar
to the first complex life forms.
75
00:06:55,253 --> 00:06:59,715
Most are soft-bodied
and rooted to the seafloor.
76
00:07:03,719 --> 00:07:05,179
All have senses.
77
00:07:06,097 --> 00:07:09,934
And some can even see their surroundings.
78
00:07:10,017 --> 00:07:12,019
[majestic music playing]
79
00:07:14,939 --> 00:07:18,234
Many get their food by filter-feeding,
80
00:07:19,819 --> 00:07:21,237
picking out plankton,
81
00:07:21,904 --> 00:07:25,616
sometimes in the most curious of ways.
82
00:07:27,535 --> 00:07:28,786
[slurps]
83
00:07:30,705 --> 00:07:32,623
[slurping]
84
00:07:33,875 --> 00:07:37,420
But not all animals here
are stuck in one place.
85
00:07:42,508 --> 00:07:43,759
Some can move,
86
00:07:44,969 --> 00:07:47,054
exploring the seafloor
87
00:07:47,138 --> 00:07:50,892
like their pioneering relatives
millions of years ago.
88
00:07:58,608 --> 00:08:03,029
It may seem like these shallows
are a kind of Eden,
89
00:08:04,489 --> 00:08:06,199
a safe haven for life.
90
00:08:07,909 --> 00:08:10,620
But this is no paradise.
91
00:08:11,204 --> 00:08:13,623
[ominous music playing]
92
00:08:17,752 --> 00:08:20,546
Living off modern-day California…
93
00:08:24,175 --> 00:08:27,011
this is a rainbow nudibranch.
94
00:08:31,140 --> 00:08:34,644
And its sluggish nature
hides a sinister side…
95
00:08:39,315 --> 00:08:42,068
because, like its ancestors,
96
00:08:42,652 --> 00:08:44,570
it's here to hunt.
97
00:08:50,660 --> 00:08:53,412
It's adapted to a life of predation.
98
00:08:54,664 --> 00:08:56,290
And its prey of choice,
99
00:08:57,750 --> 00:08:59,210
anemones.
100
00:09:05,341 --> 00:09:08,094
But like the very first predators,
101
00:09:08,177 --> 00:09:11,681
the nudibranch has room for improvement…
102
00:09:12,557 --> 00:09:14,559
[tense music playing]
103
00:09:18,187 --> 00:09:21,148
…because here, timing…
104
00:09:25,069 --> 00:09:26,445
is everything.
105
00:09:30,741 --> 00:09:32,702
Luckily for the hunter,
106
00:09:32,785 --> 00:09:35,204
its prey is anchored to the seafloor
107
00:09:36,038 --> 00:09:38,040
and can't hide forever.
108
00:09:38,124 --> 00:09:40,126
[sinister music playing]
109
00:09:52,638 --> 00:09:54,390
The anemone's fate?
110
00:09:55,016 --> 00:09:57,977
To be eaten from the inside out.
111
00:09:58,060 --> 00:10:00,062
[chomping]
112
00:10:13,159 --> 00:10:18,205
The arrival of predation
was a seismic shift in the ancient seas.
113
00:10:21,876 --> 00:10:23,419
The hunted had to adapt
114
00:10:24,295 --> 00:10:25,838
or risk extinction.
115
00:10:30,259 --> 00:10:34,388
And one group adapted
in a way never seen before.
116
00:10:38,893 --> 00:10:41,896
Despite being single animals,
117
00:10:42,730 --> 00:10:46,817
they were able to separate
into layers of individuals,
118
00:10:47,735 --> 00:10:51,030
that then broke free.
119
00:10:53,824 --> 00:10:55,034
Jellyfish.
120
00:10:55,701 --> 00:10:58,621
530 million years ago,
121
00:10:58,704 --> 00:11:04,835
they were the very first animals
to escape the seafloor and swim.
122
00:11:04,919 --> 00:11:06,712
[graceful music playing]
123
00:11:10,299 --> 00:11:12,301
[tense music playing]
124
00:11:12,385 --> 00:11:17,139
But predators were already everywhere.
125
00:11:22,395 --> 00:11:24,397
[dramatic music playing]
126
00:11:34,031 --> 00:11:36,075
Armed with venomous harpoons,
127
00:11:36,575 --> 00:11:39,870
these anemones make quick work
of baby jellyfish.
128
00:11:53,551 --> 00:11:55,052
[tense music playing]
129
00:11:56,137 --> 00:11:57,680
And they are so abundant
130
00:11:58,931 --> 00:12:01,559
escape seems impossible.
131
00:12:04,270 --> 00:12:06,272
[tense music continues]
132
00:12:21,120 --> 00:12:22,121
Caught.
133
00:12:25,040 --> 00:12:26,459
But not for long.
134
00:12:33,174 --> 00:12:34,925
[tranquil music playing]
135
00:12:41,140 --> 00:12:43,225
Free at last.
136
00:12:51,776 --> 00:12:53,778
Thanks to their ability to swim,
137
00:12:54,904 --> 00:12:58,282
jellyfish were the first
to venture out of the shallows
138
00:12:59,825 --> 00:13:01,660
and into the big blue.
139
00:13:09,502 --> 00:13:11,504
[music swells]
140
00:13:11,587 --> 00:13:13,589
[stirring music playing]
141
00:13:23,349 --> 00:13:26,393
Here, with fish yet to evolve,
142
00:13:27,520 --> 00:13:32,149
jellyfish were entirely free of predation.
143
00:13:36,278 --> 00:13:39,198
In time, others would follow.
144
00:13:39,865 --> 00:13:42,493
But more than half a billion years ago,
145
00:13:43,077 --> 00:13:46,163
the open ocean belonged to them.
146
00:13:46,247 --> 00:13:47,873
[music swells]
147
00:13:49,917 --> 00:13:51,919
[music fades]
148
00:13:58,259 --> 00:14:00,261
[water laps gently]
149
00:14:01,971 --> 00:14:04,223
For those still stuck on the seabed,
150
00:14:04,890 --> 00:14:08,853
escaping predation
required a different approach.
151
00:14:21,323 --> 00:14:22,908
This curious creature
152
00:14:24,201 --> 00:14:25,411
is a trilobite.
153
00:14:27,997 --> 00:14:31,750
And its breakthrough adaptation, armor.
154
00:14:34,253 --> 00:14:38,632
Trilobites are one of the first
in a brand-new dynasty,
155
00:14:40,259 --> 00:14:41,886
the arthropods.
156
00:14:47,808 --> 00:14:51,103
They've evolved an external skeleton,
157
00:14:51,645 --> 00:14:56,191
a shield-like shell
that protects their soft insides.
158
00:15:00,946 --> 00:15:04,283
And in these waters, they need it.
159
00:15:05,117 --> 00:15:07,119
[sinister music playing]
160
00:15:11,165 --> 00:15:13,667
This is Anomalocaris.
161
00:15:15,044 --> 00:15:17,004
A bizarre-looking animal,
162
00:15:17,087 --> 00:15:21,342
its name translates
as "the abnormal shrimp."
163
00:15:25,387 --> 00:15:29,767
And in the tropical shallows
508 million years ago,
164
00:15:31,769 --> 00:15:34,980
it's the world's first apex predator.
165
00:15:37,524 --> 00:15:39,526
[tense music playing]
166
00:15:47,493 --> 00:15:52,206
Despite the trilobite's armor,
it makes sense to keep out of sight.
167
00:16:00,339 --> 00:16:04,134
But away from the canyons,
there's nowhere to hide…
168
00:16:06,512 --> 00:16:09,098
because what makes this hunter so special…
169
00:16:11,684 --> 00:16:13,769
…is its speed.
170
00:16:17,606 --> 00:16:19,149
[dramatic music playing]
171
00:16:19,733 --> 00:16:25,948
Unlike jellyfish, Anomalocaris can swim
with both direction and pace.
172
00:16:28,325 --> 00:16:30,285
But that isn't always enough…
173
00:16:35,499 --> 00:16:41,380
because when cornered,
the trilobite's armor comes into its own.
174
00:16:47,136 --> 00:16:52,516
Rolling into a ball,
it becomes completely impenetrable.
175
00:16:55,728 --> 00:16:58,522
Even for the abnormal shrimp.
176
00:17:07,072 --> 00:17:12,661
With the coast clear, the trilobite
continues on its merry way once more.
177
00:17:17,249 --> 00:17:22,004
It's searching for one
of the ancient ocean's greatest sights…
178
00:17:22,880 --> 00:17:24,882
[stirring music playing]
179
00:17:29,845 --> 00:17:32,139
…the trilobite mating grounds,
180
00:17:32,723 --> 00:17:36,018
where thousands come together to breed.
181
00:17:38,729 --> 00:17:43,150
In the story of life,
armor has been such a success
182
00:17:43,233 --> 00:17:46,487
that today, nearly 80% of all animals,
183
00:17:46,570 --> 00:17:50,699
including insects, spiders, and crabs,
184
00:17:50,783 --> 00:17:53,744
are related to this ancient arthropod.
185
00:17:57,498 --> 00:18:01,293
But armor couldn't protect them
from everything.
186
00:18:07,216 --> 00:18:09,343
[ominous music playing]
187
00:18:18,227 --> 00:18:23,107
Forty million years later,
and a new era of life has begun,
188
00:18:24,691 --> 00:18:27,820
with more diversity than ever before.
189
00:18:32,366 --> 00:18:35,536
Here, trilobites are still in their prime,
190
00:18:36,161 --> 00:18:38,872
but their armor is even more robust…
191
00:18:42,835 --> 00:18:48,423
because on this reef,
danger comes from a new type of predator.
192
00:19:00,936 --> 00:19:04,148
Ancestors of today's octopus and squid,
193
00:19:05,774 --> 00:19:11,488
these tentacled giants are part
of a dynasty known as the cephalopods.
194
00:19:15,242 --> 00:19:17,244
[sinister music playing]
195
00:19:21,165 --> 00:19:25,377
The largest,
with a shell eight meters long,
196
00:19:26,503 --> 00:19:28,130
are Cameroceras.
197
00:19:36,138 --> 00:19:39,558
The trilobite is dwarfed
by this towering hunter.
198
00:19:42,436 --> 00:19:45,397
But it's not their size
that makes them such a threat.
199
00:19:48,233 --> 00:19:49,526
[trilobite squeaks]
200
00:19:50,819 --> 00:19:55,365
Cameroceras have evolved
a new way to catch their prey…
201
00:19:57,826 --> 00:19:59,620
even when they can't see it.
202
00:20:01,413 --> 00:20:03,415
[ominous music playing]
203
00:20:08,962 --> 00:20:13,842
Because in these waters,
they hunt using not just sight,
204
00:20:15,469 --> 00:20:16,595
but touch.
205
00:20:28,023 --> 00:20:32,903
All the trilobite can do
is try to stay out of reach.
206
00:20:39,618 --> 00:20:41,620
[ominous music fades]
207
00:20:44,498 --> 00:20:46,500
[dramatic music playing]
208
00:20:52,422 --> 00:20:53,882
With a scissor-like beak…
209
00:20:53,966 --> 00:20:55,092
[crunching]
210
00:20:55,175 --> 00:20:57,594
…able to slice through the toughest armor,
211
00:20:59,346 --> 00:21:02,516
Cameroceras dominate these seas.
212
00:21:05,143 --> 00:21:08,313
Although, there is
another important new arrival.
213
00:21:14,111 --> 00:21:16,822
Graced with a look of permanent surprise,
214
00:21:18,615 --> 00:21:20,993
this is Arandaspis…
215
00:21:23,787 --> 00:21:25,747
an early kind of fish.
216
00:21:26,581 --> 00:21:28,583
[playful music playing]
217
00:21:30,711 --> 00:21:33,005
It hasn't yet evolved a jaw,
218
00:21:33,922 --> 00:21:36,008
so can only suck up the scraps.
219
00:21:40,637 --> 00:21:42,472
But what it has evolved
220
00:21:43,348 --> 00:21:45,809
will change the course of history.
221
00:21:52,566 --> 00:21:58,155
It has a new internal skeleton
that makes it both fast and agile.
222
00:22:00,115 --> 00:22:01,491
A backbone.
223
00:22:03,201 --> 00:22:05,579
And while it may not look like much,
224
00:22:06,163 --> 00:22:10,834
fish like Arandaspis will one day
give rise to all other vertebrates.
225
00:22:11,793 --> 00:22:16,423
Amphibians, reptiles, mammals, and birds.
226
00:22:20,719 --> 00:22:25,474
But for now,
vertebrates are only at the beginning
227
00:22:26,224 --> 00:22:29,519
of a very, very long journey.
228
00:22:29,603 --> 00:22:31,396
[music ends]
229
00:22:41,156 --> 00:22:43,200
[tense ambient music playing]
230
00:22:47,621 --> 00:22:52,709
Twenty million years later,
life faced one of its greatest challenges…
231
00:22:52,793 --> 00:22:54,795
[rumbling]
232
00:22:56,129 --> 00:22:58,131
[howling wind]
233
00:22:59,257 --> 00:23:02,886
…as the climate suddenly began to cool…
234
00:23:04,304 --> 00:23:06,264
[thunder rumbles]
235
00:23:08,517 --> 00:23:12,312
…a development that was to have
dire consequences.
236
00:23:14,439 --> 00:23:16,441
[suspenseful music playing]
237
00:23:32,040 --> 00:23:36,711
Little by little,
the sea started to freeze.
238
00:23:39,840 --> 00:23:41,383
[suspenseful music continues]
239
00:23:52,727 --> 00:23:55,939
For the inhabitants
of Earth's once tropical waters,
240
00:23:57,441 --> 00:24:00,110
this was a catastrophe.
241
00:24:04,865 --> 00:24:06,867
[music fades]
242
00:24:09,119 --> 00:24:10,871
[mournful vocalizing]
243
00:24:19,045 --> 00:24:22,799
The shallow seas
became a frozen graveyard.
244
00:24:26,678 --> 00:24:29,890
The world's first mass extinction.
245
00:24:29,973 --> 00:24:31,975
[mournful vocalizing continues]
246
00:24:41,193 --> 00:24:46,698
The fatal freeze was caused
by a 60% drop in carbon dioxide.
247
00:24:49,951 --> 00:24:52,579
Without this greenhouse gas to warm it,
248
00:24:52,662 --> 00:24:55,415
the planet was plunged into an ice age.
249
00:25:01,922 --> 00:25:05,759
One that would last for 200,000 years.
250
00:25:06,718 --> 00:25:08,720
[sorrowful music playing]
251
00:25:15,852 --> 00:25:20,106
At its peak, almost half the world
was covered in ice,
252
00:25:21,024 --> 00:25:26,613
causing the demise of 85% of all life,
253
00:25:27,656 --> 00:25:31,493
lost from our family tree forever.
254
00:25:38,667 --> 00:25:40,669
With the tropical shallows gone,
255
00:25:40,752 --> 00:25:44,506
the few survivors were those
who could head to deeper waters.
256
00:25:52,138 --> 00:25:54,266
Animals like the nautilus,
257
00:25:54,349 --> 00:25:57,519
a smaller relative
of the giant Cameroceras.
258
00:26:04,693 --> 00:26:07,946
It first evolved
hundreds of millions of years ago,
259
00:26:08,697 --> 00:26:10,824
but still exists today.
260
00:26:14,327 --> 00:26:19,457
It owes its success
to the deep ocean's unchanging nature.
261
00:26:21,376 --> 00:26:26,256
Below 600 meters,
the temperature rarely fluctuates,
262
00:26:26,339 --> 00:26:29,217
making it a sanctuary of stability.
263
00:26:32,012 --> 00:26:33,930
When the Ice Age struck,
264
00:26:35,015 --> 00:26:38,226
all kinds of animals
headed into the abyss.
265
00:26:40,812 --> 00:26:44,482
But it's the cephalopods who have thrived.
266
00:26:46,484 --> 00:26:48,612
[majestic music playing]
267
00:26:52,198 --> 00:26:55,660
Today, many still haunt the deep sea…
268
00:26:58,788 --> 00:27:01,958
including octopus and squid.
269
00:27:08,256 --> 00:27:13,136
Their gelatinous bodies are unaffected
by the deep's immense pressure.
270
00:27:17,265 --> 00:27:22,687
And super senses
let them find their way in the dark.
271
00:27:27,150 --> 00:27:29,444
No longer constrained by shells,
272
00:27:29,944 --> 00:27:34,491
they've evolved
into almost every size and shape.
273
00:27:42,540 --> 00:27:46,127
But this pitch-black world
isn't theirs alone.
274
00:27:51,216 --> 00:27:55,053
Arthropods, like this spider crab,
live here too…
275
00:27:58,098 --> 00:28:00,725
feeling their way across the ocean floor.
276
00:28:04,479 --> 00:28:06,940
Alongside them, the vertebrates.
277
00:28:09,859 --> 00:28:14,197
With little food on offer,
down here, they're rare.
278
00:28:18,118 --> 00:28:22,747
Only around 10% of all fish today
live in the deep.
279
00:28:26,793 --> 00:28:29,170
This is not a place they excel…
280
00:28:31,631 --> 00:28:37,595
unlike the cephalopods, who have become
the deep's near-perfect predators.
281
00:28:45,520 --> 00:28:48,815
Something this shrimp may soon discover.
282
00:28:48,898 --> 00:28:50,900
[quiet, suspenseful music playing]
283
00:29:01,828 --> 00:29:06,750
All around it, the water twinkles
with bioluminescent plankton.
284
00:29:09,335 --> 00:29:14,424
Any disturbance, and for the briefest
of moments, they light up.
285
00:29:20,805 --> 00:29:22,432
But the shrimp has company.
286
00:29:27,520 --> 00:29:29,439
A half-concealed squid
287
00:29:30,440 --> 00:29:32,108
is watching the show.
288
00:29:34,944 --> 00:29:39,783
Its large eyes allow it to see
exceptionally well in the dark.
289
00:29:39,866 --> 00:29:41,826
[tense music playing]
290
00:29:49,876 --> 00:29:51,836
Picking out the dots of light,
291
00:29:52,545 --> 00:29:55,340
it can follow every move the shrimp makes.
292
00:29:57,842 --> 00:30:01,262
All it needs is the right moment.
293
00:30:03,890 --> 00:30:05,892
[tense music continues]
294
00:30:22,325 --> 00:30:24,619
The shrimp never saw it coming.
295
00:30:34,504 --> 00:30:36,756
With such extraordinary senses,
296
00:30:37,382 --> 00:30:43,263
perhaps it's no surprise that squid
have mastered this cold, dark world.
297
00:30:45,974 --> 00:30:48,977
But for those who lived
back in the Ice Age,
298
00:30:49,519 --> 00:30:51,896
things were beginning to heat up.
299
00:30:52,647 --> 00:30:54,649
[rumbling]
300
00:30:54,732 --> 00:30:56,734
[solemn music playing]
301
00:30:59,612 --> 00:31:01,614
[ice creaking]
302
00:31:05,159 --> 00:31:08,413
200,000 years after the big freeze,
303
00:31:10,456 --> 00:31:13,877
there appeared in the ice a vein of blue.
304
00:31:13,960 --> 00:31:16,129
[majestic music playing]
305
00:31:19,132 --> 00:31:20,300
Water.
306
00:31:22,594 --> 00:31:26,014
Carbon dioxide levels had bounced back,
307
00:31:27,724 --> 00:31:30,894
causing global temperatures to rise.
308
00:31:31,769 --> 00:31:34,314
The great melt had begun.
309
00:31:36,524 --> 00:31:40,403
Slow at first,
the thaw rapidly gathered pace.
310
00:31:50,663 --> 00:31:55,543
Before long,
glaciers hundreds of meters tall
311
00:31:55,627 --> 00:31:58,254
cascaded into the warming seas.
312
00:32:03,301 --> 00:32:05,386
[rousing vocalizing]
313
00:32:07,889 --> 00:32:09,349
Within a few millennia,
314
00:32:10,016 --> 00:32:14,312
almost half the planet's ice had melted.
315
00:32:15,605 --> 00:32:19,776
Within a few more, it had entirely gone.
316
00:32:26,199 --> 00:32:29,077
For those who had sought refuge
in the deep,
317
00:32:29,160 --> 00:32:31,704
now was a chance to head back up.
318
00:32:34,248 --> 00:32:36,250
[mysterious music playing]
319
00:32:39,629 --> 00:32:42,256
Off the coast of modern-day Australia,
320
00:32:43,591 --> 00:32:47,011
this is a young giant cuttlefish.
321
00:32:48,763 --> 00:32:51,391
Like his Ice Age ancestors,
322
00:32:51,474 --> 00:32:54,560
he's come to the shallows
in search of a mate.
323
00:33:00,400 --> 00:33:02,694
But others have got here first…
324
00:33:02,777 --> 00:33:05,196
[sinister music playing]
325
00:33:07,407 --> 00:33:10,034
…including an alpha male…
326
00:33:13,204 --> 00:33:15,915
jealously protecting his chosen partner.
327
00:33:20,086 --> 00:33:23,589
And he does not intend to share.
328
00:33:30,513 --> 00:33:33,808
But the smaller male isn't deterred.
329
00:33:35,893 --> 00:33:38,938
Instead, he bides his time
330
00:33:40,398 --> 00:33:41,524
and watches
331
00:33:43,484 --> 00:33:46,612
as a new male enters the arena…
332
00:33:48,781 --> 00:33:50,867
and signals his intention…
333
00:33:53,202 --> 00:33:54,912
to challenge the alpha.
334
00:33:56,164 --> 00:33:58,541
[tense music playing]
335
00:34:02,170 --> 00:34:06,758
With neither backing down,
a fight is inevitable…
336
00:34:06,841 --> 00:34:09,260
[dramatic music playing]
337
00:34:14,515 --> 00:34:18,478
…allowing the young male to make his move.
338
00:34:18,561 --> 00:34:20,104
[whimsical music playing]
339
00:34:20,188 --> 00:34:22,356
[dramatic music playing]
340
00:34:26,402 --> 00:34:30,031
As he approaches,
he tucks in his tentacles
341
00:34:30,990 --> 00:34:32,700
and changes color…
342
00:34:34,911 --> 00:34:36,662
to perfectly mimic
343
00:34:38,039 --> 00:34:39,373
a female.
344
00:34:42,627 --> 00:34:45,004
Using brain, not brawn,
345
00:34:45,546 --> 00:34:47,924
he sneaks straight in.
346
00:34:49,842 --> 00:34:51,844
[whimsical music playing]
347
00:34:52,553 --> 00:34:54,013
[music ends]
348
00:34:56,891 --> 00:35:01,479
The alpha now thinks
he's guarding not one female…
349
00:35:04,482 --> 00:35:05,650
but two.
350
00:35:10,321 --> 00:35:13,616
He's unaware
that this sly young interloper
351
00:35:14,492 --> 00:35:18,037
is mating with his chosen partner.
352
00:35:19,288 --> 00:35:21,290
[tranquil music playing]
353
00:35:32,635 --> 00:35:36,764
Their exceptional intelligence
and remarkable senses
354
00:35:36,848 --> 00:35:41,435
have helped cephalopods
colonize every ocean on Earth.
355
00:35:50,987 --> 00:35:52,697
Yet, in the shallows,
356
00:35:52,780 --> 00:35:57,243
they are rarely the top predators
their towering ancestors once were…
357
00:36:01,164 --> 00:36:03,624
because in the ancient seas,
358
00:36:04,917 --> 00:36:08,254
there was to be a changing of the guard.
359
00:36:08,337 --> 00:36:10,381
[suspenseful music playing]
360
00:36:22,435 --> 00:36:25,396
Seventy million years
after the great melt,
361
00:36:25,479 --> 00:36:28,566
in a period known as the Devonian,
362
00:36:28,649 --> 00:36:31,319
the vertebrates made their move.
363
00:36:31,402 --> 00:36:33,404
[sinister music playing]
364
00:36:37,742 --> 00:36:40,494
This is Dunkleosteus…
365
00:36:43,289 --> 00:36:46,792
a descendant of the tiny Arandaspis.
366
00:36:49,587 --> 00:36:54,508
But at nine meters long,
this fish is no underdog.
367
00:36:59,597 --> 00:37:04,769
Even its young, barely half its size,
are fearsome predators.
368
00:37:09,440 --> 00:37:13,903
And this juvenile
has spotted something out in the blue.
369
00:37:17,365 --> 00:37:18,574
Ammonoids,
370
00:37:19,825 --> 00:37:23,996
close relatives
of today's deep-sea nautilus.
371
00:37:25,164 --> 00:37:27,166
[tense music playing]
372
00:37:33,047 --> 00:37:34,590
Being a vertebrate,
373
00:37:34,674 --> 00:37:38,636
Dunkleosteus has the pace
to catch up with them.
374
00:37:40,805 --> 00:37:42,807
[sinister music playing]
375
00:37:45,768 --> 00:37:49,397
But the ammonoids
boast a trick of their own…
376
00:37:51,941 --> 00:37:53,734
…jet propulsion.
377
00:37:55,111 --> 00:37:58,281
Just what it needs
to outmaneuver the young fish.
378
00:37:59,073 --> 00:38:01,075
[dramatic music playing]
379
00:38:06,247 --> 00:38:07,915
As it starts to circle…
380
00:38:10,293 --> 00:38:12,295
the ammonoid does the same…
381
00:38:16,007 --> 00:38:18,009
shielding its body with its shell.
382
00:38:22,179 --> 00:38:24,181
[growling]
383
00:38:25,683 --> 00:38:29,186
Once upon a time,
this defense would have worked.
384
00:38:29,895 --> 00:38:34,025
But Dunkleosteus has a weapon
its tiny ancestors did not.
385
00:38:38,112 --> 00:38:39,363
Jaws.
386
00:38:40,573 --> 00:38:44,118
It can bite down and crush its prey.
387
00:38:49,957 --> 00:38:52,460
As long as it can find the right angle.
388
00:38:52,543 --> 00:38:54,337
[suspenseful music playing]
389
00:39:10,227 --> 00:39:12,104
Luckily for the ammonoid,
390
00:39:12,188 --> 00:39:15,983
the juvenile's jaws are not yet
strong enough to break its shell.
391
00:39:16,776 --> 00:39:18,778
[teeth clacking on shell]
392
00:39:19,487 --> 00:39:22,281
But the adult's are.
393
00:39:28,329 --> 00:39:30,331
[sinister music playing]
394
00:39:35,461 --> 00:39:37,463
[music fades]
395
00:39:37,546 --> 00:39:42,927
The pairing of backbones with jaws
was to prove a winning combination.
396
00:39:44,095 --> 00:39:47,473
So perfect that, from this moment on,
397
00:39:48,140 --> 00:39:52,144
the vertebrates would never look back.
398
00:39:53,312 --> 00:39:55,314
[rousing music playing]
399
00:40:02,530 --> 00:40:05,991
Today, there are
more than 30,000 species of fish.
400
00:40:11,038 --> 00:40:14,583
Forty times as many as the cephalopods.
401
00:40:22,550 --> 00:40:24,885
While their variety is remarkable…
402
00:40:27,263 --> 00:40:30,141
each still has that perfect pairing.
403
00:40:33,060 --> 00:40:35,396
Backbones give them speed and power…
404
00:40:38,065 --> 00:40:39,650
no matter their size.
405
00:40:43,320 --> 00:40:44,655
While jaws
406
00:40:45,489 --> 00:40:46,991
give them bite.
407
00:40:50,703 --> 00:40:52,955
But there is more to jaws than that.
408
00:40:55,416 --> 00:40:58,002
Some fish use them to protect their eggs.
409
00:40:58,919 --> 00:41:00,921
[serene music playing]
410
00:41:02,756 --> 00:41:05,092
Others to attract a mate.
411
00:41:12,725 --> 00:41:15,686
Then there's the sarcastic fringehead.
412
00:41:16,395 --> 00:41:18,147
[playful music playing]
413
00:41:21,442 --> 00:41:24,153
He doesn't just use his to catch crabs.
414
00:41:33,162 --> 00:41:38,375
He also uses them for one of the most
intimidating displays in nature…
415
00:41:41,921 --> 00:41:44,798
to rid his patch of rivals.
416
00:41:53,265 --> 00:41:57,311
For these fish, size is everything.
417
00:42:07,780 --> 00:42:09,865
[music intensifies]
418
00:42:19,333 --> 00:42:20,876
[music fades]
419
00:42:21,544 --> 00:42:25,506
Big jaws have let this fringehead
rule his strip of seafloor,
420
00:42:26,757 --> 00:42:33,222
but they've also allowed a more infamous
group of fish to rule the waves.
421
00:42:33,305 --> 00:42:35,266
[ominous music playing]
422
00:42:40,646 --> 00:42:44,775
They first appeared
more than 400 million years ago
423
00:42:45,734 --> 00:42:48,612
and have been feared ever since.
424
00:42:48,696 --> 00:42:50,698
[stabbing string music playing]
425
00:42:52,825 --> 00:42:54,827
[music intensifies]
426
00:42:54,910 --> 00:42:55,828
They are
427
00:42:57,454 --> 00:42:58,622
the sharks.
428
00:43:03,043 --> 00:43:06,171
To the winning combination
of backbone and jaws,
429
00:43:07,506 --> 00:43:10,092
they've added senses so sharp
430
00:43:10,175 --> 00:43:13,637
they can detect prey
from hundreds of meters away.
431
00:43:16,765 --> 00:43:20,352
With many also boasting size and strength,
432
00:43:21,395 --> 00:43:23,522
they are as close to perfection
433
00:43:24,523 --> 00:43:27,443
as an ocean predator can get.
434
00:43:37,536 --> 00:43:39,538
[tense music playing]
435
00:43:41,165 --> 00:43:43,626
In the sea off Western Australia,
436
00:43:44,209 --> 00:43:47,254
these fish are balled together
for protection.
437
00:43:50,341 --> 00:43:52,384
But the sharks hold back…
438
00:43:54,762 --> 00:43:58,349
because they have
a special plan of attack.
439
00:44:05,731 --> 00:44:07,650
Appearing to work as a team,
440
00:44:08,275 --> 00:44:13,238
some of the sharks rise from below
to trap the fish against the surface.
441
00:44:16,825 --> 00:44:18,619
Others come in from the side,
442
00:44:20,329 --> 00:44:23,165
corralling the shoal
away from the open ocean
443
00:44:23,832 --> 00:44:25,542
and into the shallows.
444
00:44:33,634 --> 00:44:35,511
Now numbering in their hundreds,
445
00:44:36,428 --> 00:44:38,180
the sharks play for time…
446
00:44:42,017 --> 00:44:45,062
as their prey get ever more tired.
447
00:44:49,858 --> 00:44:52,027
[sinister music playing]
448
00:44:58,283 --> 00:45:02,371
It's a hunting technique that has been
honed over millions of years.
449
00:45:04,957 --> 00:45:08,544
But the carnage starts
in the blink of an eye.
450
00:45:09,461 --> 00:45:11,714
[dramatic music playing]
451
00:45:29,857 --> 00:45:32,067
[music continues]
452
00:45:44,580 --> 00:45:46,248
[music fades]
453
00:45:51,128 --> 00:45:54,089
Virtually unchanged since the great melt,
454
00:45:55,340 --> 00:45:59,428
sharks are one of
the most successful dynasties in history.
455
00:46:03,932 --> 00:46:08,645
But they owe their rise
to the fall of their greatest rivals.
456
00:46:20,240 --> 00:46:21,909
[mysterious music playing]
457
00:46:26,747 --> 00:46:29,041
Back in the ancient seas,
458
00:46:29,124 --> 00:46:33,378
and Dunkleosteus had reigned
for 20 million years.
459
00:46:34,379 --> 00:46:36,423
[sinister music playing]
460
00:46:37,591 --> 00:46:41,678
So vicious a predator
that not even early sharks could compete.
461
00:46:47,559 --> 00:46:51,522
But Dunkleosteus was to suffer
from a devastating quirk of fate…
462
00:46:54,817 --> 00:46:56,819
[mysterious music playing]
463
00:46:57,653 --> 00:46:59,613
…caused by plankton.
464
00:47:02,825 --> 00:47:04,827
Billions of years earlier,
465
00:47:04,910 --> 00:47:07,704
plankton had been the catalyst
for animal life.
466
00:47:11,083 --> 00:47:14,795
But now,
they would almost bring it to an end.
467
00:47:20,008 --> 00:47:22,678
A sudden surge in ocean nutrients
468
00:47:23,262 --> 00:47:27,057
caused the population of plankton
to increase…
469
00:47:30,477 --> 00:47:32,479
on an unprecedented scale.
470
00:47:32,563 --> 00:47:34,565
[ominous music playing]
471
00:47:40,737 --> 00:47:46,702
As it spread through the sunlit shallows,
this thick soup began to rot…
472
00:47:49,580 --> 00:47:52,499
causing the ocean's oxygen to plummet.
473
00:48:02,426 --> 00:48:08,140
Without this critical ingredient for life,
animals started to suffocate.
474
00:48:08,223 --> 00:48:10,225
[mournful music playing]
475
00:48:18,317 --> 00:48:23,780
For those unable to escape the sludge,
there was only one possible outcome.
476
00:48:26,617 --> 00:48:27,951
Extinction.
477
00:48:31,038 --> 00:48:35,375
Dunkleosteus was one of many
to be lost from our planet.
478
00:48:43,050 --> 00:48:45,052
[mournful music continues]
479
00:48:47,095 --> 00:48:51,099
Across the world,
coastlines became littered with the dead.
480
00:49:03,779 --> 00:49:08,033
Only the lucky few,
including early sharks,
481
00:49:08,116 --> 00:49:09,660
were able to survive.
482
00:49:21,922 --> 00:49:27,010
In all, 80% of marine life
was wiped out in this,
483
00:49:27,094 --> 00:49:30,305
the world's second mass extinction.
484
00:49:32,474 --> 00:49:34,476
[music fades]
485
00:49:35,102 --> 00:49:38,981
And yet this is only half the story.
486
00:49:43,485 --> 00:49:46,530
The nutrients that caused
the plankton explosion
487
00:49:48,073 --> 00:49:50,283
didn't start out in the sea.
488
00:49:50,367 --> 00:49:52,369
[uplifting music playing]
489
00:49:53,996 --> 00:49:56,790
They were carried there from the land…
490
00:50:01,628 --> 00:50:07,759
…released by plants during one
of the most amazing events of all time…
491
00:50:15,559 --> 00:50:18,603
…the greening of planet Earth.
492
00:50:19,688 --> 00:50:21,690
[majestic music playing]
493
00:50:24,401 --> 00:50:26,987
What was once a volcanic wasteland
494
00:50:28,321 --> 00:50:32,075
was now overflowing with life.
495
00:50:32,784 --> 00:50:35,287
-[music fades]
-[creatures chirping]
496
00:50:36,455 --> 00:50:40,125
And this new world offered opportunity.
497
00:50:42,627 --> 00:50:44,921
For where plants had paved the way,
498
00:50:45,881 --> 00:50:48,133
animals would follow.
499
00:50:48,216 --> 00:50:50,218
[chirping continues]
500
00:50:51,970 --> 00:50:58,060
And before long,
the race to dominate the land would begin.
501
00:50:59,019 --> 00:51:03,273
-[dramatic music playing]
-[low growling]
502
00:51:06,735 --> 00:51:08,737
[growling, roaring]
503
00:51:08,820 --> 00:51:10,447
[dramatic music intensifies]
504
00:51:10,530 --> 00:51:12,074
[music ends]
505
00:51:13,575 --> 00:51:15,368
[rousing music playing]
37435
Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.