Others are barely larger than a grain of sand.

有些僅僅比沙粒大一些。

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

有些能釋放出地球上最致命的毒液。

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

有些則握有能使生物學得到重大突破的秘密。

They've inhabited the ocean for at least half a billion years, and they're still flourishing as the sea changes around them.

牠們棲息在海中起碼超過 5 億年，而且在不斷變化的海洋中，仍舊繁盛不衰。

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

水母是軟體海洋生物，牠們不是真的魚類。

They're part of a diverse team of gelatinous zooplankton, zooplankton being animals that drift in the ocean.

他們是「凝膠狀浮游生物」，這個多樣化家族的成員之一，浮游生物是指漂浮在海洋的動物。

There are more than 1,000 species of jellyfish, and many others that are often mistaken for them.

世界上的水母種類超過 1,000 種，還有很多經常被誤認為水母的生物。

A noted feature of jellyfish is a translucent bell made of a soft delicate material called mesoglea.

水母有個顯而易見的特徵，就是半透明的鐘形身驅是由一種稱做「中膠層」的柔軟精緻材質組成。

Sandwiched between two layers of skin, the mesoglea is more than 95% water held together by protein fibers.

像三明治般夾在兩層皮膚中間，中膠層內含超過 95% 的水份，並透過蛋白質纖維結合在一起。

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

水母可以透過收縮、放鬆牠們的鐘形身驅來推進。

They don't have a brain or a spinal cord, but a neural net around the bell's inner margin forms a rudimentary nervous system that can sense the ocean's currents and the touch of other animals.

牠們沒有腦袋或脊髓，但在鐘形結構的內緣有一組神經網，形成一個基本的神經系統，可以讓牠們感知到海洋的潮流以及其他動物的觸動。

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 through a hole in the underside of their bells.

這些凝膠狀的食肉動物以浮游生物及其他小型海洋生物為食，藉由牠們的鐘型結構下的一個孔洞。

The nutrients are absorbed by an inner layer of cells with waste excreted back through their mouths.

營養物質被細胞內層吸收後，剩餘廢棄物就再次從牠們的嘴巴排泄出來。

But the jellyfish's relatively simple anatomy doesn't prevent it from having some remarkable abilities.

但水母相對簡單的解剖構造不妨礙牠具備一些特殊能力。

One kind of box jellyfish has 24 eyes.

有一種箱型水母身上有 24 隻眼睛。

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

科學家認為牠能透過簡單的神經系統看見顏色並形成圖像。

Four of its eyes are curved upward on stalks.

其中 4 隻眼睛向上彎曲長在肉柄上。

This allows the jellyfish to peer through the surface of the water, looking for the canopy of the mangrove trees where it feeds.

這讓水母得以穿過水面窺視尋找牠賴以為生的紅樹林樹冠。

In fact, this may be one of the only creatures with a 360-degree view of its environment.

事實上，牠可能是唯一一種能夠 360 度環視周遭環境的生物。

The jellyfish's sting, which helps it capture prey and defend itself, is its most infamous calling card.

水母的蜇刺，幫助牠們捕捉獵物以及自我防衛是牠們最聲名狼藉的絕招。

In the jelly's epidermis, cells called nematocysts lie coiled like poisonous harpoons.

在水母的表皮有著刺絲囊的細胞環繞，就像一堆有毒的魚叉。

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

當牠們被碰到時就會觸發有如爆炸般的強力射擊，

It exerts over 550 times the pressure of Mike Tyson's strongest punch to inject venom into the victim.

這樣的射擊壓力大約是拳王 Tyson 最強一擊的 500 倍，將毒液注入受害者中。

Some jellyfish stings barely tingle, but others cause severe skin damage.

一些水母的蜇刺幾乎不會被感覺到，但有一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, making it one of the most potent poisons of any animal in the world.

一種箱型水母的毒液可以在 5 分鐘內使一個成人死亡，讓牠成為世界上最毒的動物之一。

Other jellyfish superpowers are less lethal.

其他水母的能耐就沒那麼致命了。

One species of jellyfish glows green when it's agitated, mostly thanks to a biofluorescent compound called green fluorescent protein, or GFP.

有一種水母在激動的時候會發出綠光，主要多虧一種生物螢光化合物，「綠色螢光蛋白」 簡稱 GFP 。

Scientists isolated the gene for GFP and figured out how to insert it into the DNA of other cells.

科學家將 GFP 的基因獨立出來並搞清楚如何將它插入其他細胞的 DNA。

There, it acts like a biochemical beacon, marking genetic modifications, or revealing the path of critical molecules.

作為一種生化信標標示出基因修飾處，或顯示出關鍵分子的路徑。

Scientists have used the glow of GFP to watch cancer cells proliferate, track the development of Alzheimer's, and illuminate countless other biological processes.

科學家已經利用 GFP 的亮光來觀察癌細胞的增殖、追蹤阿茲海默症的發展，並照亮無數其他生物學的發展進程。

Developing the tools and techniques from GFP has netted three scientists a Nobel Prize in 2008, and another three in 2014.

從 GFP 發展出來的工具與技術讓 3 位科學家在西元 2008 年，還有另外 3 位在西元 2014 年都獲得諾貝爾獎。

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

但水母可能是地球上最成功的生物。

Ancient fossils prove that jellyfish have inhabited the seas for at least 500 million years, and maybe go back over 700 million.

古化石顯示出水母已經棲息在海中起碼 5 億年，或許達到 7 億年之久。

That's longer than any other multiorgan animal.

這比任何其他多器官生物都還久。

And as other marine animals are struggling to survive in warmer and more acidic oceans, the jellyfish are thriving, and perhaps getting even more numerous.

而且當其他海洋動物正奮鬥存活在逐漸暖化與酸化的海洋中時，水母正成長茁壯，可能數量會變得更加龐大。

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

有些水母一個晚上就能產下多達 45,000 個卵。

And there's some jellyfish whose survival strategy almost sounds like science fiction.

還有一些水母的生存策略聽起來就像是科幻小說的劇情 。

When the immortal jellyfish is sick, aging, or under stress, its struggling cells can change their identity.

當一隻永生水母生病、變老或處於壓力之下時，牠的奮鬥細胞可以改變牠們的特性。

The tiny bell and tentacles deteriorate and turn into an immature polyp that spawns brand new clones of the parent.

微小的鐘型身驅跟觸手就會退化返回未成熟的水螅形態，產出全新的母體複製體。

As far as we know, these are the only animals who found a loophole when facing mortality.

據我們所知，這是唯一一種面對死亡時，能找到漏洞的生物。

That's pretty sophisticated for species that are 95% water and predate the dinosaurs.

對一個全身含有 95% 水份並比恐龍還早存活於世上的物種來說，牠們真的是很精明老練。