我们星球上的生命（2023）

The latest model is built for speed.
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.
如果按照人类的比例放大
If scaled up to human proportions,
它的奔跑速度
it would run
超过每小时1000公里
at over 1,000 kilometers per hour.
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.
它的大脑跟不上
His brain can't keep up.
在追逐猎物的过程中
He must frequently stop to get his bearings
它必须经常停下来确认方向
while hunting down his next victim.
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...
因为有时候猎手也会成为猎物
because sometimes the hunter can also be the hunted.
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.
它更喜欢等待猎物靠近
She prefers to wait for prey to come to her.
在节肢动物的争斗中
In the battle of the arthropods,
飞行往往能决定生死
flight would often make the difference between life and death.
3亿多年前
More than 300 million years ago,
一群节肢动物
one group of arthropods
成为率先上天的生物
were the first creatures to take to the skies.
翅膀的进化
And the evolution of wings
最终将使它们在全球范围内取得成功
would eventually launch them to global success.
昆虫
The insects.
今天地球上的昆虫
Today, for every human on the planet,
超过人类数量的10亿倍
there are more than a billion insects.
它们是地球上数量最多的动物
They are the most abundant group of animals on Earth.
（3.1亿年前）
尽管它们如今非常成功
Despite their current success,
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.
蜻蜓
Dragonflies.
它们的飞行几乎堪称完美
Their flight is as close to perfect as it gets.
四片灵活的翅膀
Four flexible wings,
可以独♥立♥控制
independently controlled,
使它们拥有无与伦比的机动性
give them unparalleled mobility.
它们可以朝任何方向飞行
They can fly in any direction,
完成最急的转弯
pull off the tightest turns...
加速比战斗机更快
and accelerate faster than a fighter jet.
如此成功的设计
A winning design
已经保持了数亿年 几乎不变
that has remained almost the same for hundreds of millions of years.
然而在同一片史前沼泽之中
And yet, living in the same prehistoric swamps,
另一群动物正在经历巨变
another group of animals were undergoing their own radical change.
在水面下方
Beneath the surface,
脊椎动物继续进化
vertebrates had continued to evolve...
一种新型鱼类蓬勃发展
and a new type of fish was thriving,
叶鳍鱼
the lobe-finned fish.
有一些长成了巨大而可怕的捕食者
Some grew to be monstrous predators.
在这个鱼吃鱼的世界
In this fish-eat-fish world,
大就是好
it pays to be big.
较小的鱼 可以在浅海寻求庇护
For the smaller ones, there's refuge in the shallows...
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.
它们肌肉发达且随机应变
Muscular and highly versatile,
叶鳍与其他鱼的鳍不同
they are different to those of other fish.
不仅有助于游泳
Not only do they help them swim...
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...
帮助它们从水中爬出
and help them crawl out of the water.
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...
呼吸空气的能力
the ability to breathe air.
不是通过腮 而是通过原始的肺呼吸
Not through gills but through primitive lungs.
这些进化一起作用
Together, these evolutionary advances
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.
争夺新世界的竞赛已经开始
The race was on to colonize this new world.
但对于这些叶鳍鱼来说
But it was already too late
已经太晚了
for these lobe-finned fish.
其他动物先它们一步完成了这种转变
Others had made this transition before them.
比如三米长的石炭鲵
Like the three-meter-long Anthracosaurus...
已经长出腿来
...that had already found its feet.
从鳍到肢的进化用了数百万年
The evolution from fin to limb took millions of years.
但一旦完成
But once completed,
陆地上的生活将永远改变
life on land would never be the same again.
两栖动物的时代
The age of amphibians
已经开始
had begun.
今天有超过8000个两栖动物物种
Today, there are more than 8,000 species of amphibian.
这是一个奇怪却多样的种群
A peculiar but diverse group...
有蝾螈
...of newts,
青蛙
frogs,
火蝾螈
salamanders,
还有蟾蜍
and toads.
虽不再是曾经的巨兽
Not quite the giants they once were,
但仍然是成功的猎手
but still successful hunters...
拥有独特的杀手风格
...with their own killer style.
石炭鲵出现之后几亿年
Hundreds of millions of years after Anthracosaurus,
沼泽仍然是两栖动物的根据地
swamplands remain a stronghold for amphibians.
在欧洲的多瑙河三角洲
Here in Europe's Danube delta,
湖侧褶蛙成千上万
marsh frogs live in their thousands
已经成为专业的昆虫猎手
and have become expert insect hunters...
尤其喜欢捕食蜻蜓
with a particular taste for dragonflies.
蜻蜓有全方位视觉
Thanks to their wraparound vision,
要抓住它可不容易
catching one isn't easy.
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.
蹼有助于腾空
Webbed feet help them get airborne.
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.
即便如此
Even so,
飞行中的蜻蜓仍然很难捕获
dragonflies in flight can be just too hard to catch.
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.
是时候换一种方法了
Time to take a different approach.
一只雌性蜻蜓在水上产卵
A female laying eggs in the water.
半浸在水中
Half-submerged,
它应该是一个比较容易对付的目标
she should be an easier target.
但蜻蜓实在太快了
The dragonflies are just too fast.
还会翻滚动作
And they can barrel-roll.
又没抓住
Missed again.
但青蛙生性坚持不懈
But frogs are nothing if not persistent.
虽然命中率低
Despite the low hit rate,
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.
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...
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.
水
Water.
这是哥斯达黎加的草莓箭毒蛙
This is the strawberry dart frog of Costa Rica.
它的蝌蚪危在旦夕
Her tadpoles are in mortal danger.
小水洼几乎快要干涸
Their tiny puddle, almost dry.
唯一的逃生方法
Their only means of escape
就是爬到母亲的背上
is on their mother's back.
难点在于找到水
The hard part is finding water.
幸运的是
Luckily...
它知道该去哪里
...she knows exactly where to go.
在它上方20米处
Twenty meters above her,
一株凤梨科植物蓄集雨水
a bromeliad collects rainwater.
对它珍贵的蝌蚪来说 是完美的池塘
The perfect pool for her precious tadpole.
但是它首先必须上去
But first, she must get there...
一次跳一步
one hop at a time.
它仅有人类指甲般大小
Barely the size of a human thumbnail,
这对它来说是珠穆朗玛峰
this is her own personal Everest.
终于安全了
Safe at last.
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...
它们永远无法摆脱与水的联♥系♥
they never escaped their tie to water...
当地球上的环境剧变时
a tie that would be their undoing when conditions on Earth...
这种联♥系♥将使它们毁灭
radically changed.
（3亿年前）
在石炭纪
During the period known as the Carboniferous,
地球各大♥陆♥合为一体
Earth's great land masses merged,
超级大♥陆♥“盘♥古♥大♥陆♥”诞生
and the supercontinent of Pangaea was born.
随着陆地变干
As the land dried,
广阔的沼泽开始消失
the vast swamps began to disappear.
由于缺水 多数两栖动物苦苦挣扎