答案是琥珀,樹液的化石。
We find all kinds of prehistoric insects, plants, and even small reptiles trapped within amber.
我們能發(fā)現(xiàn)琥珀里面裹著各種史前昆蟲、植物甚至小型爬行動(dòng)物。
We also find gas balls.
我們還能發(fā)現(xiàn)氣泡。
And so scientists were able to drill into these pieces of amber and extract the oxygen bubbles within them.
所以科學(xué)家們能鉆進(jìn)這些琥珀把里面的氣泡提取出來。
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This is how we know what the percentage of oxygen used to be.
我們就這樣了解到過去空氣中的氧氣百分比。
Higher oxygen levels also allowed plant eaters to be enormous.
更高的氧氣水平同樣讓以植物為食者長得巨大。
Allosaurus was perfectly suited for taking on big game.
異特龍非常適合捕獵大型獵物。
When you look at the foot and the leg of Allosaurus, it's certain quite powerful.
要是看看異特龍的腳和腿,就知道它們相當(dāng)有力。
I mean, Allosaurus was a large therapods of its time, one of the top predators.
我是說,異特龍是當(dāng)時(shí)一種大型獸腳類,頂級(jí)掠食者之一。
So not only was it built to carry the weight of the animal, but also, was no doubt, used to hold down carcasses and things like that.
所以它的身體設(shè)計(jì)不僅要承載體重,毫無疑問也被用于抓住尸體和之類的東西。
We have to remember what was Allosaurus eating.
我們別忘了異特龍都吃什么。
They were eating some of the biggest animals the earth has ever seen.
它們吃的是一些有史以來最大的一些動(dòng)物。
Allosaurus was feeding on sauropods - animals that are multi-times the size of our largest mammals today, the elephant.
異特龍捕食蜥腳類恐龍,這些動(dòng)物的體型是如今最大的哺乳動(dòng)物大象的好幾倍。
And they were bringing these animals down.
異特龍能擊敗這些動(dòng)物。
Allosaurus is an example of how all life adapts and changes to the environment.
異特龍是所有生命根據(jù)環(huán)境進(jìn)行適應(yīng)和改變的范例。
First, you have trees that began to grow to outrageous sizes and it's also when we see the long-necked dinosaurs emerging to take advantage of these tall trees.
首先,樹木開始長得異常茁壯,也是這個(gè)時(shí)候我們看到長頸恐龍開始出現(xiàn)來利用這些高大樹木。
Camarasaurus was the most common and successful dinosaur of that time.
圓頂龍是那一時(shí)期最普遍、最成功的恐龍。
Then Allosaurus had to grow huge because he prey was becoming so huge.
之后異特龍也得長得巨大,因?yàn)樗鼈兊墨C物在變得非常龐大。
So in a sense you could say Allosaurus grew big because trees grew big.
所以在某種程度上可以說異特龍是因?yàn)闃淠咀兇蠖兇蟆?/p>
This was a good all-purpose generalized animal and I think that's one of the reasons for its success.
這真是一種萬能的動(dòng)物,我覺得這是它成功的原因之一。
It was very widely distributed and fairly abundant.
它的分布范圍很廣,數(shù)量也很多。
And that probably was because it was generalized enough that it could adapt to a wide variety of different environments, take a wide variety of prey, and as a result, flourished.
很可能是因?yàn)槭亲銐蛉嫠阅軌蜻m應(yīng)各種不同的環(huán)境,應(yīng)對(duì)個(gè)各種各樣的獵物,結(jié)果,就繁盛了。
Its ability to adapt allowed Allosaurus to become one of the most successful predators of the late Jurassic.
它的適應(yīng)能力讓異特龍變成了晚侏羅紀(jì)時(shí)期最成功的掠食者之一。
Its long stiff tail gave it excellent balance, allowing it to hunt in the open and in dense forests.
又硬又長的尾巴使它擁有出色的平衡能力,在開闊地和密林之中都能狩獵。