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  • Without water, a human can only survive for about 100 hours.

    沒了水,人類最多只能撐 100 小時

  • But there's a creature so resilient that it can go without it for decades.

    但有一種如此強韌的生物,沒水也能存活幾十年

  • This one millimeter animal can survive both the hottest

    這個一毫米長的動物,能夠存活於

  • and coldest environments on Earth,

    地球上最熱和最冷的環境

  • and can even withstand high levels of radiation.

    甚至可以承受高強度的放射線

  • This is the tardigrade,

    見見緩步動物

  • and it's one of the toughest creatures on Earth,

    世界上最強悍的其中一種動物

  • even if it does look more like a chubby, eight-legged gummy bear.

    雖然牠看起來比較像一隻肥嘟嘟的八腳小熊軟糖

  • Most organisms need water to survive.

    絕多數生物需要水才能存活

  • Water allows metabolism to occur,

    水讓新陳代謝得以維持

  • which is the process that drives all the biochemical reactions

    才能驅使細胞中的生物化學反應

  • that take place in cells.

    開始作用

  • But creatures like the tardigrade, also known as the water bear,

    但像緩步動物,或熟知為水熊蟲的這種生物

  • get around this restriction with a process called anhydrobiosis,

    能夠藉由一種稱為脫水生活 (anhydrobiosis) 的過程不受規則束縛

  • from the Greek meaning life without water.

    anhydrobiosis 源自希臘文,意思是無水的生活

  • And however extraordinary, tardigrades aren't alone.

    雖然很特殊,但緩步動物門並非個案

  • Bacteria,

    細菌、

  • single-celled organisms called archaea,

    單細胞生物古菌、

  • plants,

    植物

  • and even other animals can all survive drying up.

    甚至其他動物,都能撐過乾巴巴的環境

  • For many tardigrades,

    對於許多緩步動物來說

  • this requires that they go through something called a tun state.

    這意味著要進入一個叫做大桶狀態的過程

  • They curl up into a ball,

    他們踡縮成一顆球

  • pulling their head and eight legs inside their body

    把他們的頭和八隻腿收進身體裡

  • and wait until water returns.

    等待水再次到來

  • It's thought that as water becomes scarce

    認知是當水源不足

  • and tardigrades enter their tun state,

    緩步動物進入大桶狀態時

  • they start synthesize special molecules,

    他們開始合成特殊的分子

  • which fill the tardigrade's cells to replace lost water

    這些分子藉由組成基質,填滿緩步動物的細胞

  • by forming a matrix.

    代替流失的水分

  • Components of the cells that are sensitive to dryness,

    細胞中對乾燥敏感的組成物

  • like DNA,

    如 DNA、

  • proteins,

    蛋白質、

  • and membranes,

    和細胞膜

  • get trapped in this matrix.

    都被鎖在基質裡

  • It's thought that this keeps these molecules locked in position

    人們認為這能夠讓分子維持狀態

  • to stop them from unfolding,

    以免他們散開、

  • breaking apart,

    分崩離析、

  • or fusing together.

    或融合在一起

  • Once the organism is rehydrated, the matrix dissolves,

    一旦有機體逢遇甘霖,基質就會溶解

  • leaving behind undamaged, functional cells.

    留下完好無損、功能完善的細胞

  • Beyond dryness, tardigrades can also tolerate other extreme stresses:

    不只是乾燥環境,緩步動物也能忍受其他極端壓力:

  • being frozen,

    被冰凍、

  • heated up past the boiling point of water,

    在超過沸點的沸水中加熱、

  • high levels of radiation,

    高強度的放射線

  • and even the vacuum of outer space.

    甚至是外太空真空狀態

  • This has led to some erroneous speculation

    這因此引發一些錯誤的猜測

  • that tardigrades are extraterrestrial beings.

    以為緩步動物是外星物種

  • While that's fun to think about,

    這樣想頗好笑的

  • scientific evidence places their origin firmly on Earth

    因為科學證據確立了他們源自地球

  • where they've evolved over time.

    並且經過了時間演化

  • In fact, this earthly evolution has given rise

    事實上,緩步動物在地球上的演化

  • to over 1100 known species of tardigrades

    至今已有超過 1100 種已知品種

  • and there are probably many others yet to be discovered.

    並且或許還有許多尚未被發現的品種

  • And because tardigrades are so hardy, they exist just about everywhere.

    正因為緩步動物如此硬派,幾乎到處都看得到他們的蹤影

  • They live on every continent, including Antarctica.

    他們遍及各大洲,包括南極洲

  • And they're in diverse biomes including deserts,

    而且他們存在在多元的生物群系,包含沙漠、

  • ice sheets,

    冰原、

  • the sea,

    海洋、

  • fresh water,

    淡水、

  • rainforests,

    雨林、

  • and the highest mountain peaks.

    和山脈頂峰

  • But you can find tardigrades in the most ordinary places, too,

    但你也能在最尋常的地方找到緩步動物

  • like moss or lichen found in yards,

    比如庭院裡的苔蘚和青苔

  • parks,

    以及公園

  • and forests.

    和森林裡的

  • All you need to find them is a little patience and a microscope.

    要找到他們,你只需要一些耐心和一台顯微鏡

  • Scientists are now trying to find out whether tardigrades use the tun state,

    現在科學家還在試著探究緩步動物是否還會利用他們的大桶狀態

  • their anti-drying technique,

    也就是抗乾燥技術

  • to survive other stresses.

    來抵禦其他生存壓力

  • If we can understand how they, and other creatures,

    如果我們能夠了解他們和其他生物

  • stabilize their sensitive biological molecules,

    是如何穩固他們敏感的生理分子

  • perhaps we could apply this knowledge to help us stabilize vaccines,

    或許我們也能將這項技術應用到穩固疫苗

  • or to develop stress-tolerant crops that can cope with Earth's changing climate.

    或是研發出能夠適應地球氣候變遷的抗壓作物

  • And by studying how tardigrades survive

    藉由研究緩步動物

  • prolonged exposure to the vacuum of outer space,

    如何活過長時間的外太空真空狀態

  • scientists can generate clues about the environmental limits of life

    科學家能夠歸究出環境限制生命的線索

  • and how to safeguard astronauts.

    還有如何保護外太空人

  • In the process, tardigrades could even help us answer a critical question:

    在此同時,緩步動物或許甚至能幫助我們回答這個重大問題:

  • could life survive on planets much less hospitable than our own?

    生物是否可以在生存環境劣於地球的星球生存?

Without water, a human can only survive for about 100 hours.

沒了水,人類最多只能撐 100 小時

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B2 中高級 中文 美國腔 TED-Ed 動物 生物 狀態 地球 細胞

【TED-Ed】見識一下地球上最強悍的動物--托馬斯-布斯比 (【TED-Ed】Meet the tardigrade, the toughest animal on Earth - Thomas Boothby)

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    a412087311 發佈於 2021 年 01 月 14 日
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