argument150 [0710G 戴三个表冲刺小组] 第16次作业

pinuoUID: 2328081

150The following is a letter to the editor of an environmental magazine.
"The decline in the numbers of amphibians worldwide clearly indicates the global pollution of water and air. Two studies of amphibians in Yosemite National Park in California confirm my conclusion. In 1915 there were seven species of amphibians in the park, and there were abundant numbers of each species. However, in 1992 there were only four species of amphibians observed in the park, and the numbers of each species were drastically reduced. The decline in Yosemite has been blamed on the introduction of trout into the park's waters, which began in 1920 (trout are known to eat amphibian eggs). But the introduction of trout cannot be the real reason for the Yosemite decline because it does not explain the worldwide decline."

1. 作者没有给出证据说明trout不是Yosemite的amphibians减少的原因，即使trout不是原因也可能有其他的原因，
1> Park管理不善，
2> 有人非法猎杀
2. 即使Yosemite的原因是pollution，并不能解释全球的amphibians减少是pollution造成的。

TOPIC: ARGUMENT150 - The following is a letter to the editor of an environmental magazine.
"The decline in the numbers of amphibians worldwide clearly indicates the global pollution of water and air. Two studies of amphibians in Yosemite National Park in California confirm my conclusion. In 1915 there were seven species of amphibians in the park, and there were abundant numbers of each species. However, in 1992 there were only four species of amphibians observed in the park, and the numbers of each species were drastically reduced. The decline in Yosemite has been blamed on the introduction of trout into the park's waters, which began in 1920 (trout are known to eat amphibian eggs). But the introduction of trout cannot be the real reason for the Yosemite decline because it does not explain the worldwide decline."

WORDS: 442          TIME: 00:30:24          DATE: 2007-8-11 0:25:49

In the letter, the author asserted that it is the global pollution of water and air that cause the decline in the numbers of amphibians worldwide. To support his argument, the author cite the studies of amphibians in Yosemite National Park. The argument are problematic in several aspects, thus render the conclusion unconvincing as it stands.

To begin with, the author provided absolute no evidence to role out the possibility that trout in the Yosemite National Park declined lead to the decline of  amphibians there. Since trout , which are know to eat amphibian eggs,are intriductedd to park's waters in1920. It is highly possible it is trout that contribute to the decline of amphibian from 1915 to 1992.

In addition, even the author provide evidence trout is not the cause, there are other factors may cause the decline of amphibians rather than the pollution which the auther claimed responsible for the decline. First, the poor management of park can inflict on the animals in the park, perhaps there are decline of other animals along with amphibian. Second, the illegal hunting may greatly theat the life of amphibian, for economic interests, the illegal hunting of amphibian may increased in the past several years, thus the previewing hunting can be one cause of decline of amphibian.  Without ruling out this factors, the author cannot blindly conclude it is pollution cause the decline.

And the author fail to present evidence there were water and air pollution in the park during the period in which the specieds of amphibian declined and the numbers of each species were drastically reduced. If there were no significant pollution in the park , the study may lend absolutely no support to author's final argument.

Finally, even the author provide evidence that there were pollutions in the past several years and it is these pollutions that lead to the decline of amphibians in Yosemite National Park, it is unconvincing pollution caused the decline of maphibians worldwide. The conditions in the other areas of the world may far different from the one in Yosemite National Park. In some areas there may be less serious pollutions but dramatic decline of amphibian while in other areas the more serious pollution and increasing of amphibian coexists.

In sum, to convince me that it is pollution that are responsible for the decline of amphibian worldwide, the author shoud provide evidence trout is not the cause of decline of amphibian in Yosemite National Park, and instead pollution there is the cause. To better assess the argument, I need the evidence the other area which seen the decline of amphibian share the same condition with Yosemite National Park.

[ 本帖最后由 pinuo 于 2007-8-11 00:37 编辑 ]