評論
打印
The thing about extinction events is that, of course they're very bad for the animals that go extinct, but they open up a door of opportunity for a lot of other animals and plants.
其實就滅絕事件來說，當然對走向滅絕的動物來說很糟糕，不過這也為很多其它動物和植物，打開了機會之門。
And basically once certain species disappear, then other species will evolve and change and take over their place in that particular ecosystem or habitat.
基本上一旦某種物種消失了，其它物種就會進化，改變并取代它在特定生態環境或棲息地的位置。
Ultimately, it would be the giant asteroid that would end the reign of the dinosaurs.
最終，一顆巨大的小行星終結了恐龍的王朝。
But that deadly space missile would take another 250 million years to finally reach the earth.
不過那顆致命的太空導彈還要再花兩億五千萬年才會到達地球。
In the meantime, the dinosaurs waged a savage battle for survival.
在此期間，恐龍發動了一場慘烈的生存之戰。
144 million years ago, at the end of the Jurassic era, many dinosaur species became victims of climate changes that probably brought about their first extinction.
一億四千四百萬年前，在侏羅紀末期，很多恐龍種類成了氣候變化的受害者，這大概帶來了它們的首次滅絕。
But a host of others managed to rise to power.
不過其它一些恐龍設法登上統治地位。
More efficient plant eaters like Gastonia and Tenontosaurus were able to fill the void left by their predecessors, and in turn, new predators appeared along with them.
更多高效的植食者，比如加斯頓龍和腱龍，能夠填補前輩留下的空缺，反過來，新的掠食者也就隨之出現。
At the top of the food chain are the Raptors.
在食物鏈的頂端是迅猛龍。
These predators were more advanced than their earlier cousins.
這些掠食者比它們早期的親戚更加先進。
This is when raptors, like Deinonychus and Utahraptor made their debut.
正是這個時候，迅猛龍，比如恐爪龍和猶他盜龍，初次登場。
Over the next 79 million years, dinosaurs continued as the unchallenged rulers.
接下來的七千九百萬年，恐龍仍是不可動搖的統治者。
No other animals could match their size, power or ferocity.
沒有其它動物能比得了它們的體型、力量或兇殘。
By the end of the Cretaceous period, global environmental changes saw the emergence of tougher, more fibrous species of plants.
到了白堊紀末期，全球的環境變化帶來了更堅韌、纖維更多的植物物種。
To take advantage of these new food sources, specially adapted herbivores evolved.
為了能夠利用這些新的食物來源，進化出了特化的植食動物。
By the end of the Cretaceous, we had some very advanced dinosaurs.
到了白堊紀末期，出現了一些非常先進的恐龍。
There were lots of species of Ceratopsians, these were the horn dinosaurs.
有很多種角龍，這些是長角的恐龍。
And there were an abundance of duckbilled dinosaurs called Hadrosaurs.
還有很多嘴部像鴨喙的恐龍，稱之為鴨嘴龍。
Both of these groups had remarkably advanced teeth and jaw design which allowed them to eat a wider variety of plants.
這兩類恐龍都有相當先進的牙齒和頜部構造，使之能夠吃更多種類的植物。
And the predators also had become more advanced.
掠食者也變得更加先進。
Dinosaurs like Albertosaurus was able to hunt cooperatively with other members of their own family, while raptors took pack hunting to a whole new level.
像阿爾伯特龍這樣的恐龍與家族中的其它成員能夠進行合作狩獵，而迅猛龍更是將群體獵食帶到了全新高度。
But sitting atop all of these was Tyrannosaurus Rex.
不過首屈一指的是雷克斯暴龍。
He was the ultimate predator in earth's history.
它是地球歷史中的終極掠食者。
And yet with all these evolutionary advancements, they literally disappeared in the blink of an eye.
但盡管有著所有這些進化優勢，它們轉瞬間就消失了。
65 million years ago, the giant asteroid that had been hurtling towards earth finally struck.
在六千五百萬年前巨大的小行星經過飛向地球的漫長的歲月終于到達。
Nothing was safe.
沒什么是安全的。
All the dinosaurs in the world at that time became extinct along with a lot of the big reptiles that sort of looked like dinosaurs, things like Mosasaurs and Plesiosaurs in the ocean,
那時全球所有的恐龍都走向滅絕，一起的還有很多看起來有點像恐龍的大型爬行動物，像是海洋里的滄龍和蛇頸龍，
and, on land of course the Tyrannosaurus Rex, and Nanotyrannus, and Triceratops, and all the duck-bill dinosaurs, and all the little raptors and so forth.
當然陸地上的霸王龍，矮暴龍，三角龍和所有的鴨嘴龍，還有所有的小迅猛龍等等。
It was a pretty much extinction of everything.
基本上所有的都滅絕了。
For many years, scientists were baffled by this massive extinction.
很多年來，科學家們為這次大滅絕而困惑。
It seemed incredible that so much carnage could have been caused by a single, sudden, catastrophic event.
似乎很難相信一次單獨突發的災難性事件能帶來那么多的大屠殺。
The time in geological history that separates that end of the Cretaceous from the Tertiary Period is marked with a very distinctive band of clay.
在地質歷史中分開白堊紀末期和第三紀的那段時間被記錄在非常獨特的一層黏土中。
You can see this thin band in locations throughout the world and it clearly marks the spot where something major had taken place.
在全球都能看到這薄薄的一層黏土，它非常清晰地標出發生過重大事件的地點。
Below it we find dinosaurs, pterosaurs and a variety of giant sea reptiles.
在這層黏土之下我們發現了恐龍、翼龍和各種大型海洋爬行動物。
But above that line, we don't see any evidence of these same creatures.
不過在那條線以上，我們沒有看見過任何這些同種生物的證據。
So this layer clearly represents that something dramatic had happened on earth that caused a mass extinction in a very short time.
所以這一層黏土清晰地表明地球上曾發生過劇烈變化，并在很短時間內導致了大規模滅絕。
The layer that separates the periods is called the K-T boundary.
這區分兩個紀元的土層被稱作KT界限層。
