The ferocious predatory dinosaurs of Cretaceous Sahara - Nizar Ibrahim

1,957,235 views ・ 2017-06-06

TED-Ed


请双击下面的英文字幕来播放视频。

翻译人员: Cherry Zhou 校对人员: Lipeng Chen
00:08
There are few places on Earth less hospitable to life
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地球上很少有这么不适合生物生存的地方
00:11
than the bone-dry Sahara Desert.
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能比得上极其干燥的撒哈拉沙漠了。
00:14
Yet it wasn't always this way.
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但它本来并不是这样的。
00:17
100 million years ago, during a period known as the Mid-Cretaceous,
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1亿年前的白垩纪中期,
00:22
a gargantuan river system flowed across the region
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有一个庞大的河流体系流经这个区域,
00:25
from modern day Egypt to Morocco.
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从现代埃及延伸至摩洛哥。
00:28
The whole world at that time would look rather different to us.
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那时的世界面貌跟我们如今所看到的截然不同。
00:32
The continents had yet to assume their current positions.
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各大洲还没有呈现出现时的地理位置。
00:35
Extreme temperatures were common
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极端温度的出现是很常见的事情,
00:37
and fierce storms made life unpredictable.
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还有猛烈的暴风雨让生存变得不可预测。
00:41
Dinosaurs flourished on land,
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恐龙在陆地上繁衍不息,
00:43
pterosaurs roamed the skies,
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翼龙漫游在天空中,
00:45
and giant marine reptiles and sharks swam in warm seas.
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大型海洋爬行动物和鲨鱼在温暖的大海中畅游。
00:51
Small mammals, our ancestors, lived quite literally in the shadow
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我们的祖先即小型的哺乳动物生活在
00:56
of these extraordinary creatures.
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这些非凡生物的阴影里。
00:59
In this world of huge predators,
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这个大型捕食者的世界,
01:02
the River of Giants,
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还有巨人之河,
01:03
which is what some call this region of what is now northern Africa,
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有人说这里就是现在的北非地区,
01:07
stood out as particularly dangerous.
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因极其危险而引人关注。
01:10
In most ecosystems, it's lonely at the top of the food chain.
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在绝大多数生态系统中, 位于食物链顶端的生物是孤寂的。
01:14
There usually isn't enough prey to sustain many predators.
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通常没有足够的猎物能够供养那么多捕食者。
01:18
Yet an incredible variety of aquatic prey species in the river-based ecosystem
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然而,在以河流为基础的生态系统中 有各种各样的水生猎物,
01:23
may have allowed a large and diverse population of apex predators to coexist.
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得以让数量庞大品种多样 而且处于食物链顶端的捕食者共存。
01:30
We know this thanks to a wealth of fossils we found in an area
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多亏了我们在某个区域里发现的大量化石, 我们才知道了这一切,
01:34
called the Kem Kem Beds.
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这个区域名字叫卡玛卡玛地层。
01:36
Many of the predators we've discovered had head and body shapes
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我们所发现的许多捕食者都具有头部和身体形态,
01:39
that made them uniquely adapted to hunt the different types and sizes
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这使它们能特异性适应于不同类型和大小
01:44
of aquatic prey.
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的水生生物的猎捕。
01:46
This allowed many Kem Kem predators to take full advantage
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这让卡玛卡玛捕食者能充分利用
01:49
of the one abundant food source in this environment: fish.
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在这个环境里一种充足的食物来源:鱼。
01:55
This also allowed them to avoid direct competition
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这得以让它们避免直接的竞争,
01:58
with the predators going after land-loving animals.
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不用跟其他捕食者一起追逐陆地动物。
02:03
Prey species in the river system had to contend with attacks from all sides,
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河流体系中的猎物需要应对来自四面八方的攻击,
包括天上飞的捕食者的攻击。
02:08
including from above.
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02:10
Flying reptiles dominated the skies.
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飞行类爬行动物在天空中占支配地位。
萨哈瑞卡翼龙的翅膀展开后可达九米,
02:13
Alanqa Saharica had a wingspan of up to nine meters,
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02:17
and long slender jaws that helped it snatch fish
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还有它细长的下颚能够协助它捕捉鱼类
02:20
and small terrestrial animals.
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和小型的陆生生物。
02:24
At least seven different types of crocodile-like predators
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至少有七种不同类型的鳄鱼类捕食者
02:27
patrolled the waterways,
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在水域中巡视,
02:29
including the roughly ten-meter-long Elosuchus.
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其中包括了身长大概10米的埃罗鳄。
02:33
And multiple species of T-rex-sized carnivorous dinosaurs called theropods,
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还有一类被统称为是兽脚亚目恐龙的 有着霸龙王体型的肉食性恐龙,
02:38
lived side by side.
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它们和平共存着。
02:41
In the River of Giants, Spinosaurus was king.
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在巨人之河中,棘龙是国王。
02:45
This 15-meter-long dinosaur was even longer than T-rex,
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这种恐龙身长15米,比霸王龙还要长,
02:49
with short muscular hind legs,
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它有强壮的短小后腿,
02:51
a flexible tail,
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一条灵活自如的尾巴,
和宽大的脚。
02:53
and broad feet.
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02:54
It's two-meter-high sail warned other creatures of its fearsome size
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它两米高的帆翼让其他生物惧怕于它的体型,
02:59
and may have also been used to attract mates.
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或许还被用来吸引雌性恐龙。
03:03
Spinosaurus' long slender jaws were spiked with conical teeth,
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棘龙细长的下颚中长满了锥形牙齿,
03:07
perfect for swiftly clamping down on slippery aquatic prey.
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能快速地将表面光滑的水生猎物完美制服。
03:13
This apex predator, as well as its ecosystem,
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这种位于食物链顶端的捕食者, 还有它赖以生存的生态系统,
03:16
is unparalleled in the history of life on Earth.
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在地球的生命史上是前所未有的。
03:21
All that's left of these fearsome predators are fossils.
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但这些可怕的捕食者最后剩下的只有化石。
03:25
About 93 million years ago, sea levels rose,
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大约在9300万年前,海平面上升,
03:28
submerging the Kem Kem region in a shallow sea.
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将卡玛卡玛地区淹没成一片浅海。
03:32
Tens of millions of years later,
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数千万年后,
03:34
an asteroid impact,
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小行星撞击,
火山爆发,
03:36
volcanic eruptions,
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03:37
and associated changes in climate
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气候随之改变,
03:40
wiped out the dinosaurs, pterosaurs, and many other groups of animals and plants,
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恐龙、翼龙、还有许多动植物都因而灭绝,
03:45
including their unique ecoysystems.
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这其中包括了它们独一无二的生态系统。
这种大规模的灭绝为新物种如鸟类,
03:49
That mass extinction paved the way for the rise of new kinds of birds,
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03:53
larger mammals,
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还有大型哺乳动物的诞生创造了条件,
03:54
and eventually us.
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最终人类得以诞生。
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