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  3. The Relationship Between Dinesaurs and Birds The once radical notion that birds descended from dinosaurs—or may even be dino

The Relationship Between Dinesaurs and Birds The once radical notion that birds descended from dinosaurs—or may even be dino

admin2014-06-13  60
问题             The Relationship Between Dinesaurs and Birds
    The once radical notion that birds descended from dinosaurs—or may even be dinosaurs, the only living branch of the family that ruled the earth eons ago—has got stronger and stronger since paleontologists first started taking it seriously a couple of decades ago. Remarkable similarities in bone structure between dines and birds were the first clue. Then came evidence, thanks to a series of astonishing discoveries in China’s Liaoning province over the past five years, that some dinosaurs may have borne feathers. But a few scientists still argued that the link was weak; the bone similarities could be a coincidence, they said. And maybe those primitive structures visible in some fossils were feathers, but maybe not. You had to use your imagination to see them.
    Not anymore. A spectacularly preserved fossil of a juvenile dinosaur announced by a team of paleontologists from the Chinese Academy of Geological Sciences and New York City’s American Museum of Natural History in the latest issue of Nature, is about as good a missing link as anyone could want.
    "It has things that are undeniably feathers," exults Richard Prum, of the University of Kansas Natural History Museum, an expert on the evolution of feathers. "But it is clearly a small, vicious theropod similar to the velo-ciraptors that chased the kids around the kitchen in Jurassic Park."
    The find helps cement the dinosaur-bird connection, but it also casts new light on the mystery of why nature invented feathers in the first place. For the better part of a century, biologists have assumed that these specialized structures evolved for flight, but that’s clearly not true. "The feathers on these dinosaurs aren’t flight-worthy, and the animals couldn’t fly," says paleontologist Kevin Padian, of the University of California, Berkeley. "They’re too big, and they don’t have wings." So what was the original purpose of feathers? Nobody knows for sure; they might have been useful for keeping dines dry. distracting predators or attracting mates, as peacocks do today.
    But many biologists suspect that feathers originally arose to keep dinosaurs warm. The bone structure of dinosaurs shows that, unlike modem reptiles, they grew as fast as birds and mammals—which dovetails with a growing body of evidence that dines were, in fact, warm-blooded. Says Padian: "They must have had a high basal metabolic rate to grow that fast. And I wouldn’t be surprised if they had some sort of skin covering for insulation when they were small." Says Norell. "Even baby tyrannosaurs probably looked like this one."
    At the rate feathered dinosaurs are turning up, it shouldn’t take long to solidify scientists’ understanding of precisely how and why feathers first arose and when the first birdlike creature realized they were useful for flight. Meanwhile, kids had better get used to the idea that T-rex may have started life looking an awful lot like Tweety Bird.
We learn from the beginning of the passage that______.
选项 A、scientists are split as to whether birds descended from dinosaurs
B、the bone similarities between birds and dinosaurs are a coincidence
C、fossils have proven that birds evolved from dinosaurs
D、the idea that birds are connected with dinosaurs has always been taken seriously
答案A
解析 推理判断题。文章开头用“me once radical notion”来说明这个观点曾经被视为极端学说，接着在下文中作者写道：“But a few scientists still argued that the link was weak”。由此可见对于鸟类是否起源于恐龙，科学家们有不同的看法。
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