鳍状肢可能确实是水生生物的必要反应,海龟、鲸鱼和儒艮也有鳍状肢。
Flippers may indeed be a necessary response to aquatic life, turtles, whales, and dugongs also have them.
它们向我们展示了进化过程中半成品的样貌,而完全进化的结果是鲸鱼和儒艮。
They show us what the intermediates might have been like, on the way to extreme cases such as whales and dugongs.
然而,从某种程度上讲,海龟并没有像鲸鱼或儒艮一样完全回到水中生活,因为它们依旧在海滩上产卵。
However, they are, in one respect, less fully given back to the water than whales or dugongs, for turtles still lay their eggs on beaches.
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