小学6年级 - 议论文 阅读指导

　In on the origin of species survival of the fittest in natural selection.
　survival of the fittest, rabbit ancestors living in the wild, because of its small needs a sensitive hearing, so that the first time to escape to preserve their lives in distress, and long ears helps to collect sound, and short ears rabbit is eliminated, long ears of generations of breeding, the ear is more and more long … …
　Today, the rabbits were domesticated, do not need long ears to collect the information of what, so gradually also appeared a short eared rabbit, and there are some remains long ears.