The problem with the above explanation is that the Japanese starry flounder population is almost exclusively left-eyed, and natural selection never promotes a purely less advantageous variation. As other explanations proved equally untenable, biologists concluded that there is no important adaptive difference between left-eyedness and right-eyedness, and that the two characteristics are genetically associated with some other adaptively significant characteristic. This situation is one commonly encountered by evolutionary biologists, who must often decide whether a characteristic is adaptive or selectively neutral. As for the left-eyed and right-eyed flatfish, their difference, however striking, appears to be an evolutionary red herring.
1. According to the text, starry flounder differ form most other species of flatfish in that starry flounder
[A] are not basically bilaterally symmetric.
[B] do not become asymmetric until adulthood.
[C] do not all share the same asymmetry.
[D] have both eyes on the same side of the head.
2. Which of the following best describes the organization of the text as a whole?
[A] A phenomenon is described and an interpretation presented and rejected.
[B] A generalization is made and supporting evidence is supplied and weighed.
[C] A contradiction is noted and a resolution is suggested and then modified.
【2014考研英语阅读经典试题及答案(12)】相关文章:
★ 2013年6月英语六级考试备考快速阅读试题模拟与解析(2)
最新
2016-10-18
2016-10-11
2016-10-11
2016-10-08
2016-09-30
2016-09-30