[Big Fish]03月03日argument150--By rokre2tt

rokre2ttUID: 2714355

依然第一次，希望大家狠狠拍砖

The author of the letter concludes that the global water and air pollution leads to the reduction in the number of amphibians worldwide. To support his conclusion, the author lists two studies' result. First, the species of the amphibians have declined from seven to four between 1915 and 1992 in Yosemite National Park in California, at the same time the numbers of each species have diminished largely. Second, the introduction of trout results the reducing of amphibians in the park for the trout eats the eggs of amphibian. But the author indicates that the introduction of trout won't be the reason for the Yosemite decline because the worldwide decline can't be explained by it. However, I find there are some flaws in the argument of the author.

First of all, there are not sufficient evident to prove the introduction of trout leads to the decline in Yosemite even we know that the trout may eat amphibian eggs. The decline may be caused by other reasons, such as the predators of these amphibians are increasing during these years, the climate has been changing, but the author doesn't mention. Since we can't judge whether the introduction of trout is the reason, it's uncertain that it will lead to the global decline of course.

Second, the decline of the species and the numbers of each species can't represent the decline in the worldwide. The author only notes the sample of Yosemite National Park, probably the species of amphibians in other area of the world is increasing. Even in another park of California, there may be more amphibians than before. But the author doesn't supply more data about this.

Third, even the global amphibians decline during these years, no one can be sure that the reason is the global pollution of water and air without sufficient evidence. There may be other reasons which are ignored by the author. For example, the market needing to the amphibians may increase so that more of them are preyed by people. As the author doesn't consider it, the conclusion that the worldwide water and air pollution results the decline of the global amphibians is not creditable.

All in all, since the author doesn't offer sufficient evidence that the global amphibians decline these years, and couldn't prove there is contact between the decline of global amphibians and the worldwide pollution of water and air, the conclusion of the author is not substantial. To get a right result, there should be more messages about the worldwide data of amphibians and how the pollution of water and air cause the decline of amphibians.