Jellyfish predate dinosaurs. How have they survived so long? - David Gruber

譯者: Yueh-Lun Huang 審譯者: Helen Chang

有些比藍鯨還長

Some are longer than a blue whale.

Others are barely larger than a grain of sand.

有些則只有沙粒般的大小

One species unleashes one of the most deadly venoms on Earth.

有些能釋放地球上最致命的毒液

Another holds a secret that's behind some of the greatest breakthroughs in biology.

有些則握有突破生物學的最大秘密

They've inhabited the ocean for at least half a billion years,

牠們棲息在海洋至少五億年

and they're still flourishing as the sea changes around them.

並在不斷變化海洋中，持續地繁榮成長

Jellyfish are soft-bodied sea creatures that aren't really fish.

水母是軟體海洋生物，而非魚類

They're part of a diverse team of gelatinous zooplankton,

牠們是多樣化的 「膠質浮游動物」的成員之一

zooplankton being animals that drift in the ocean.

浮游動物指的是漂浮在海洋的動物

There are more than 1,000 species of jellyfish,

總共有 1000 多種的水母

and many others that are often mistaken for them.

還有很多經常被誤認為水母的生物

A noted feature of jellyfish is a translucent bell

水母的一個特徵是牠半透明的傘狀身軀

made of a soft delicate material called mesoglea.

由柔軟細膩的「中膠層」所構成

Sandwiched between two layers of skin,

夾在兩層皮膚之間

the mesoglea is more than 95% water held together by protein fibers.

「中膠層」由超過 95% 的水 和蛋白質纖維所組成

The jellyfish can contract and relax their bells to propel themselves.

水母可藉由收縮傘狀的身體來推進

They don't have a brain or a spinal cord,

牠們沒有腦或脊髓

but a neural net around the bell's inner margin

但在傘狀的內緣有一套神經網

forms a rudimentary nervous system

形成一個粗淺的神經系統

that can sense the ocean's currents and the touch of other animals.

使牠們能感受到海洋的潮流

及其他動物的觸動

Jellyfish don't have typical digestive systems, either.

水母也沒有典型的消化系統

These gelatinous carnivores consume plankton and other small sea creatures

這些膠狀食肉動物以浮游生物

和小型海洋生物為食

through a hole in the underside of their bells.

藉由牠們傘狀身體下的一個口

The nutrients are absorbed by an inner layer of cells

營養物質被細胞內層所吸收

with waste excreted back through their mouths.

廢物同樣由嘴巴排泄出

But the jellyfish's relatively simple anatomy

但水母相對簡單的構造

doesn't prevent it from having some remarkable abilities.

並不抵觸牠一些顯著的能力

One kind of box jellyfish has 24 eyes.

有一種箱型水母具有 24 隻眼睛

Scientists think it can see color and form images within its simple nervous system.

科學家認為牠能在其簡單的神經系統中 看見顏色並形成圖像

Four of its eyes are curved upward on stalks.

其中 4 隻眼睛向上彎曲並追蹤

這可以讓牠穿過水面窺視

This allows the jellyfish to peer through the surface of the water,

looking for the canopy of the mangrove trees where it feeds.

並尋找維生的紅樹林樹冠

In fact, this may be one of the only creatures

事實上，牠可能是唯一的生物

with a 360-degree view of its environment.

擁有 360 度的環境視野

The jellyfish's sting, which helps it capture prey and defend itself,

水母的刺有助於捕捉獵物並保護自己

is its most infamous calling card.

也是最惡名昭彰的連環殺手鐧

In the jelly's epidermis,

水母的表皮中

cells called nematocysts lie coiled like poisonous harpoons.

布滿著如同有毒的魚叉般， 盤繞的「刺絲胞」

When they're triggered by contact, they shoot with an explosive force.

當牠們被接觸時，會觸發爆炸般的射擊

It exerts over 550 times the pressure of Mike Tyson's strongest punch

相當於泰森拳頭的 550 倍壓力

to inject venom into the victim.

將毒液注入受害者

一些水母的蟄刺幾乎不被感覺到

Some jellyfish stings barely tingle,

but others cause severe skin damage.

但有些會造成嚴重的皮膚損傷

The venom of one box jellyfish can kill a human in under five minutes,

一隻箱型水母的毒液 可以在五分鐘內殺死一個人

making it one of the most potent poisons of any animal in the world.

使其成為世界上最毒的動物之一

Other jellyfish superpowers are less lethal.

其他常見的水母就不那麼致命了

One species of jellyfish glows green when it's agitated,

有一種水母會在激動時發出綠光

mostly thanks to a biofluorescent compound called green fluorescent protein,

主要是由於一種生物螢光化合物 名為「綠色螢光蛋白」

or GFP.

簡稱 GFP

Scientists isolated the gene for GFP

科學家分離出 GFP 的基因

and figured out how to insert it into the DNA of other cells.

並弄清楚如何將其插入 其他細胞的 DNA

There, it acts like a biochemical beacon,

當作是生化信標

marking genetic modifications,

標記基因修飾

or revealing the path of critical molecules.

或透露關鍵分子的路徑

Scientists have used the glow of GFP to watch cancer cells proliferate,

科學家們已經使用 GFP 的光芒來 觀察癌細胞的增值

track the development of Alzheimer's,

及追蹤阿茲海默症的發展

and illuminate countless other biological processes.

並照亮其他無數的生物過程

Developing the tools and techniques from GFP

從 GFP 開發的工具和技術

has netted three scientists a Nobel Prize in 2008,

使 2008 年的三位科學家

以及 2014 年的另外三位 獲得諾貝爾獎

and another three in 2014.

But it's jellyfish who may be the most successful organisms on Earth.

但是，水母可能是地球上最成功的生物

Ancient fossils prove that jellyfish have inhabited the seas

古代化石證明水母棲息在海洋

for at least 500 million years,

至少 5 億年

and maybe go back over 700 million.

甚至達 7 億年

That's longer than any other multiorgan animal.

這活得比其他多器官動物都還要長

And as other marine animals are struggling to survive

當其他的海洋動物 在變暖及酸化的海洋中掙扎生存時

in warmer and more acidic oceans,

水母正蓬勃地發展

the jellyfish are thriving,

and perhaps getting even more numerous.

也許會茁壯成更龐大的數量

It doesn't hurt that some can lay as many as 45,000 eggs in a single night.

有些水母能在一晚產下 45,000 顆卵

And there's some jellyfish whose survival strategy

還有一些水母

其生存策略聽起來幾乎是科幻小說

almost sounds like science fiction.

When the immortal jellyfish is sick, aging, or under stress,

當不朽的水母生病、老化或在壓力下時

its struggling cells can change their identity.

體內奮鬥的細胞可以改變其特性

微小的傘狀身體和觸鬚會退化

The tiny bell and tentacles deteriorate

轉變為未成熟的水螅體階段

and turn into an immature polyp

that spawns brand new clones of the parent.

產下全新的母體複製

As far as we know, these are the only animals who found a loophole

據我們所知

這些是唯一在面臨死亡時 發現漏洞的動物

when facing mortality.

That's pretty sophisticated for species that are 95% water

對於含 95% 水且早於恐龍的物種來說， 牠是非常複雜的

and predate the dinosaurs.