托福阅读真题+题目+答案：Metabolic Options for Dinosaurs

托福阅读真题+题目+答案：Metabolic Options for Dinosaurs

Whether dinosaurs were ectothermic (cold-blooded, with body temperatures that fluctuate in response to the environment) or endothermic (warm-blooded, with mechanisms for internal temperature regulation) is intriguing. Most paleontologists once assumed that dinosaurs were lethargic, slow moving, and stereotypically ectothermic-like their reptilian ancestors, and exemplified by a lizard. Beginning in 1972, paleontologist Robert Bakker began to advocate that endothermy was present in all dinosaurs. His reasons were based on his interpretation of their anatomy as indicating that they were active, lively creatures, as well as on ecological factors that he interpreted from the fossil record. In one study analyzing the numbers of predators compared to prey dinosaurs currently known, Bakker argued that the ratio mirrored that of ecosystems made up of extant endotherms. Lauded for creativity but soundly criticized for logical flaws in his analysis, Bakker nonetheless inspired a higher level of debate over dinosaur metabolism. He offered other circumstantial evidence for dinosaur endothermy, such as their erect gait (upright manner of walking) and mammal or birdlike microstructure of bones.

1.According to paragraph 1, how were Bakker’s arguments about endothermy in all dinosaurs received by other paleontologists of the time?

A.They dismissed his views because they believed Bakker was mistaken about the microstructure of dinosaur bones

B.They objected to the extent of debate that Bakker's views inspired on the topic of dinosaur metabolism

C.They disagreed with Bakker’s classification of known dinosaurs into predators and prey.

D.They were impressed with the originality of Bakker’s views but regarded his analysis of the data as problematic in its logic

Understanding the metabolic systems of dinosaurs would provide clues to their behavior. If dinosaurs were "cold-blooded, " they may have spent much of their time moving in and out of the sun or shade to regulate their body temperature. If they were“warm-blooded” dinosaurs would have been more active, moving about at will, day and night. Having an answer to this question would also help us understand the relationship of dinosaurs to modern animals, such as birds and other reptiles, as well as help us understand what were important factors in their evolution and extinction patterns.

2.According to paragraph 2, understanding the metabolisms of dinosaur aids in understanding all of the following EXCEPT

A.why dinosaurs were more common in areas with greater sunlight

B.the relationship of dinosaurs to modern birds and reptiles

C.how dinosaurs evolved

D.how active dinosaurs could have been

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