Scientists studying the physiology of dinosaurs have long debated whether dinosaurs were warm- or cold-blooded. Those who suspect they were warm-blooded point out that dinosaur bone is generally fibro-lamellar in nature; because fibro-lamellar bone is formed quickly, the bone fibrils, or filaments, are laid down haphazardly. Consistent with their rapid growth rate, warm-blooded animals, such as birds and mammals, tend to produce fibro-lamellar bone, whereas reptiles, which are slow-growing and cold-blooded, generally produce bone in which fibrils are laid down parallel to each other. Moreover, like the bone of birds and mammals, dinosaur bone tends to be highly vascularized, or filled with blood vessels. These characteristics, first recognized in the 1930’s, were documented in the 1960’s by de Ricqlès, who found highly vascularized, fibro-lamellar bone in several groups of dinosaurs. In the 1970’s, Bakker cited these characteristics as evidence for the warm-bloodedness of dinosaurs. Although de Ricqlès urged caution, arguing for an intermediate type of dinosaur physiology, a generation of paleontologists has come to believe that dinosaur bone is mammalianlike. In the 1980’s, however, Bakker’s contention began to be questioned, as a number of scientists found growth rings in the bones of various dinosaurs that are much like those in modern reptiles. Bone growth in reptiles is periodic in nature, producing a series of concentric rings in the bone, not unlike the growth rings of a tree. Recently, Chinsamy investigated the bones of two dinosaurs from the early Jurassic period (208-187 million years ago), and found that these bones also had growth rings; however, they were also partially fibro-lamellar in nature. Chinsamy’s work raises a question central to the debate over dinosaur physiology: did dinosaurs form fibro-lamellar bone because of an innately high metabolic rate associated with warm-bloodedness or because of periods of unusually fast growth that occurred under favorable environmental conditions? (Although modern reptiles generally do not form fibro-lamellar bone, juvenile crocodilesraised under optimal environmental conditions do.) This question remains unanswered; indeed, taking all the evidence into account, one cannot make a definitive statement about dinosaur physiology on the basis of dinosaur bone. It may be that dinosaurs had an intermediate pattern of bone structure because their physiology was neither typically reptilian, mammalian, nor avian.
GWD-9-Q33
The author of the passage would be most likely to agree that the “caution” (line 29) urged by de Ricqlès regarding claims about dinosaur physiology was
A. unjustified by the evidence available to de Ricqlès
B. unnecessary, given the work done by Bakker and his followers
C. indicative of the prevailing scientific opinion at the time D. warranted, given certain subsequent findings of other scientists
E. influential in the recent work of Chinsamy
文中这句话是什么意思？A错在什么地方？不是说“This question remains unanswered; indeed, taking all the evidence into account, one cannot make a definitive statement about dinosaur physiology on the basis of dinosaur bone.”么。。。作者: suners 时间: 2011-5-23 22:50
选项A说caution被dR的证据证明是无根据的。文中没有提到。文章只说了dR发现了highly vascularized, fibro-lamellar bone in several groups of dinosaurs。虽然有如此发现，dR并没有下结论，而是在B下了warm-bloodedness结论后，urged caution。
dR提醒学者们要谨慎下结论，说会有一个intermediate type of dinosaur physiology，虽然有dR的上述观点，一代学者还是认为恐龙的骨头是类似mammal的。之后，对于B的观点开始有不同意见。
一直到最后，文章总结说这个问题无答案，也许是有一个intermediate pattern of bone structure。也就是说，dR的caution还是有根据的。那些之后反对B的研究发现都是支持这个intermediate pattern的证据。作者: arthurman 时间: 2011-5-24 06:33
Although de Ricqlès urged caution, arguing for an “intermediate” type of dinosaur physiology与后文探讨的新研究结果所揭示的过渡性、可变性是一致的，说明它对后来的研究起了一定的作用作者: thinkingape 时间: 2011-5-24 20:17
