2. 考研
  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  41
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 last paragraph that______.
选项 A、a baby dinosaur looks like a bird
B、T-rex is a kind of dinosaur figure familiar to kids
C、living feathered dinosaurs can still be found in certain parts of the world
D、scientists understand precisely how and why feathers first arose
答案B
解析 推理判断题。本文全文都在讲鸟类与恐龙之间的关系，并在最后一段预测随着越来越多长羽毛的恐龙的化石的出现，科学家们将能够了解第一个像鸟一样的生物何时知道羽毛可用于飞翔的。然后作者说孩子们最好习惯T．rex may have started life looking an awful lot like Tweety Bird这样的想法。显然，T．rex应该是一个恐龙，而且既然要让孩子们习惯恐龙长得像小鸟，那么显然孩子们是熟悉T．rex这个形象的。
转载请注明原文地址:https://kaotiyun.com/show/p2K4777K
0

考研英语一

相关试题推荐
随机试题
最新回复(0)