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First, what we call a chance mutation. A tiny genetic change occurred in that one Notothenioid species.
第一個(gè)是我們稱為的偶然突變。在那種南極魚的基因中發(fā)生了微小的改變。
Its DNA allowed for the production of a special protein, a protein that prevents the fish from freezing.
它的基因產(chǎn)生了一種特殊的蛋白質(zhì)，這種蛋白質(zhì)能保護(hù)南極魚不受凍。
The way this...this anti-freeze protein works is: it binds to any ice crystals that form inside the fish.
這種抗凍蛋白工作的原理是：它會(huì)附在魚類體內(nèi)的每一個(gè)冰晶上。
This binding action prevents the ice crystals from growing larger. And this is what prevents Notothenioids from freezing.
這種粘附能防止冰晶變大。這就能保護(hù)南極魚不受凍了。
Now, at that time, the waters the Notothenioids inhabited were still not freezing cold, so the protein didn't really make a difference as far as the fish's survival.
在那時(shí)候，南極魚所在水域還沒有那么冷，所以這種蛋白對(duì)于魚類生存來說，并沒有起很大作用。
But this would change, because in the same period of geologic time there was a shift in the earth's continental plates.
但這很快就會(huì)改變，因?yàn)樵谕坏刭|(zhì)時(shí)期，地球的大陸板塊發(fā)生了變化。
Continental drift caused Antarctica to move apart from the landmass of South America
大陸漂移導(dǎo)致南極洲從南美大陸中分離出來，
and to drift into the Southern Polar Region. This resulted in a powerful water current encircling Antarctica,
漂流到南極區(qū)域。這導(dǎo)致南極洲被一股強(qiáng)水流環(huán)繞，
which prevented the Antarctic waters from mixing with warmer water.
阻止了南極洲水域和溫度更高的水融合。
So the southern ocean, isolated from that warm airflow from the north, cooled down drastically,
所以，南部海域與來自北方的暖氣流隔絕了，大幅度降溫，
to the kinds of sub-freezing temperatures we associate with it today.
達(dá)到了低于結(jié)冰點(diǎn)的溫度，也就是今天的溫度。
Now, most fish species couldn't survive in this frigid environment and they became extinct.
大部分魚類在如此寒冷的環(huán)境下都無法生存，很快滅絕了。
But that one Notothenioid species, with its unique ability to produce that anti-freeze protein, thrived.
但那種南極魚，有了獨(dú)一無二的制造抗凍蛋白的能力，茁壯成長。
It had virtually the entire southern ocean to itself! So? Well, there was little or no competition for food or space.
基本上整個(gè)南部海域都是它的了！所以？那兒幾乎沒有關(guān)于食物和生存空間競爭。
You might think of it as...um...as a...a kind of ecological vacuum. And the Notothenioids exploited fully.
你大概能把它當(dāng)成……一種生態(tài)真空。南極魚充分利用了這一點(diǎn)。
The species migrated into different habitats throughout the southern ocean.
這種魚遷徙到不同的棲息地，遍布整個(gè)南部海域。
And its population increased dramatically, with various sub-populations migrating into different parts of the ocean.
魚類數(shù)量大幅增加，發(fā)展出很多不同的亞種，遷徙到海洋的不同區(qū)域。
