英语听力:探索发现 2012-06-15 恐龙是怎样的炼成的—12(在线收听) |
It’s an incredible idea. But most experts now believe that today’s birds are the direct descendants of ancient dinosaurs. So does that mean birds actually are dinosaurs?
Yes. Absolutely.
How can you be sure about that?
You have evidence from the skeletal anatomy. You have evidence from the shape of the eggs and the microstructure of the eggshell, the discovery about a wealth of feathered dinosaurs, animals that are unquestionably dinosaurs and yet have feathers. They looked just like the feathers on modern birds.
It’s a discovery that revolutionizes the way we see dinosaurs. Even some tyrannosaurs were feathered. But the relationship between birds and dinosaurs can tell us much more than simply what they may have looked like.
So does this mean that we can use living birds to help us understand dinosaurs?
Absolutely. You know you have 10,000 living species of birds that are providing you an enormous amount of information that you can use to understand the biology of the ancient dinosaurs.
It’s quite amazing. But it also makes a certain degree of sense when really you look at them.
If we want to learn about how the ancient dinosaurs moved and even how quickly they ran, few animals can tell us more than ostriches. They evolved on an early branch of the avian family tree. And like dinosaurs they are related to, they are large, bipedal and flightless.
I have some living dinosaurs here to take a look at.
Hello, ladies.
They’re all ladies, are they?
Yes. Yes. They are a bit more manageable when they are females.
Dr John Hutchinson is based at the Royal Veterinary College just outside London. He’s one of the world’s leading experts on dinosaur movement and Luis has been consulting him to make sure his T. Rexes reflect the latest theories.
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原文地址:http://www.tingroom.com/lesson/yytltsfx/2012/244662.html |