题目内容

收藏纠错

题目材料：

During the Pleistocene epoch, several species of elephants isolated on islands underwent rapid dwarfing. This phenomenon was not necessarily confined to the Pleistocene, but may have occurred much earlier in the Southeastern Asian islands, although evidence is fragmentary. Several explanations are possible for this dwarfing. For example, islands often have not been colonized by large predators or are too small to hold viable predator populations. Once free from predation pressure, large body size is of little advantage to herbivores. Additionally, island habitats have limited food resources, a smaller body size and a need for fewer resources would thus be favored. Interestingly, the island rule is reversed for small mammals such as rodents, for which gigantism is favored under insular conditions.

The primary purpose of the passage is to

Aquestion the plausibility of one explanation sometimes offered for the dwarfing of certain species living on islands
Bargue that dwarfing of certain species living on islands occurred prior to the Pleistocene
Ccite evidence suggesting that dwarfing may have adverse consequences for some species living on islands
Dpresent some possible explanations for the dwarfing of certain species living on islands
Econtrast the effects of insular conditions on species with large body size and species with small body

D显示答案

登录后才可以添加做题笔记哦，还没有账号？马上注册

· 相关考点

主旨目的题

以上解析由考满分老师提供。

题目讨论

已经输入 0 个字标记为提问，会有更多小伙伴帮你解答提交

全部讨论

只看提问

按时间排序

按点赞数排序

拓展练习

练习记录

最新提问

题目内容

题目讨论