argument150 【1106G】gelivable小组 第1次作业

luohuiroseUID: 2995407

The author of this letter assert that the decline in the numbers of amphibians worldwide is an indication of the global pollution of water and air.To support the conclusion,the author first notes a decline in Yosemite National Park in California between 1915 and 1992,and acknowledged that trout,which was began to be introduced into the park in 1920,are known to eat amphibian eggs.Nevertheless,the author willy-nilly claims that the introduction of trout cannot be the real reason for the Yosemite decline because it does not explain the worldwide decline.At first glance,the author's assertion seems to be appealing,while clearly examining the reasoning,we may find the reasoning contain some facts which are unconvincing.

Firstly,the author failed to proved that global pollution cause the decline in the numbers of amphibians,meanwhile ruling out other environmental factors which may influence the habitat of amphibians.Other phenomenon may have effect on the numbers of amphibians.With all other possible explanations the author cannot convince me the pollution is the cause of the worldwide amphibian decline--or even the decline in Yosemite alone.

Secondly,even if I concede that pollution is the cause of amphibian decline,the author doesn't prove affirmative evidence ruling out and prematurely ignore the relationship between the decline of amphibians and the introduction of trout.As it infers,trout are known to eat amphibian eggs,which can be an element cause the decline.This is an fallacious reasoning unless the author can provide persuasive evidence to refute that the decline in Yosemite was indeed cause by trout.

Thirdly,with the instance--two studies of amphibians in Yosemite Park between 1915 and 1992,it does not follow that pollution is the cause of the decline.This comparison of numbers of amphibians reveals the sharp decline,but the single sample is insufficient to draw any general conclusion about the reason for a worldwide amphibian decline.Without other samples from diverse geographic locations,I cannot accept the author's sweeping generalization about the decline of amphibians and global pollution.

To sum up,the conclusion lacks of credibility,the author has overlooked or chosen to ignore many aspects of the conclusion.To strengthen the reasoning,the author should find more links between the decline of amphibians and the environmental pollution.

luohuiroseUID: 2995407

分论点的提纲：
1.除了环境污染，还有可能是其他环境因素造成amphibian数量锐减。
2.Trout也有可能是Y Park中amphibian数量减少的原因。
3.文章中举的例子是特殊样本，不能得出全球环境污染导致amphibian减少的结论。因为公园中可能有某些特殊的环境因子。