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标题: GWD TN24 T-4-Q5-Q7 [打印本页]

作者: napoleon8424    时间: 2010-9-25 20:08     标题: GWD TN24 T-4-Q5-Q7

Although many lines of evidence indicate that birds evolved from ground-dwelling theropod dinosaurs, some scientists remain unconvinced. They argue that theropods appeared too late to have given rise to birds, noting that Archaeopteryx lithographica – the oldest known bird – appears in the fossil record about 150 million years ago, whereas the fossil remains of various nonavian maniraptor theropods – the closest known relatives of birds – date only to about 115 million years ago. But investigators have now uncovered bones that evidently belong to nonavian maniraptors dating to the time of Archaeopteryx. In any case, failure to find fossils of a predicted kind does not rule out their existence in an undiscovered deposit. Skeptics also argue that the fused clavicles (the “wishbone”) of birds differ from the unfused clavicles of theropods. This objection was reasonable when only early theropod clavicles had been discovered, but fossilized theropod clavicles that look just like the wishbone of Archaeopteryx have now been unearthed. Finally, some scientists argue that the complex lungs of birds could not have evolved from theropod lungs, an assertion that cannot be supported or falsified at the moment, because no fossil lungs are preserved in the paleontological record.
Q5答案是E吗?我怎么觉得D也对呢?
Q7是D吗?想不明白为啥是 D


作者: stucashS    时间: 2010-9-26 06:40

同问,尤其是Q7,我怎么都闹不明白!请求哪位大牛给些指导!谢谢!
作者: 小月潇湘    时间: 2010-9-26 20:33

Skeptics also argue that the fused clavicles (the “wishbone”) of birds differ from the unfused clavicles of theropods

关于Q7 定位这句话

不过同问Q5
作者: msufcufou    时间: 2010-9-27 06:38

同问7
怎么会是D?




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