ARGUMENT150 鳟鱼鳟鱼~好吃的鳟鱼

xiemeng2370UID: 2749773

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: 391
TIME: 00:30:00
DATE: 2010-2-7 10:50:11
主一：无证据排除引进鳟鱼不对
主二：即使不是鳟鱼还有他因
主三：即使Y是因为污染，也不代表全球都是
This letter concludes that the decline in the numbers of amphibians worldwide indicates the global pollution of water and air. To support this argument, the author cites two studies only in Yosemite National Park to confirm his or her conclusion-- the number of species of amphibians and the numbers of each species both dramatically reduced during 77 years. But the reason of that decline not lies in the introduction of trout into the park's waters, because it does not explain the worldwide decline. However, this argument suffers a series of logical problems and critical flaws, and it is therefore wholly unpersuasive.

To begin with, the author fails to substantiate the decline in Yosemite is not due to the introduction of trout. There is nowhere more ridiculous than the reason of eliminating the possibility of the introduction is the worldwide decline of Yosemite. Even though the decline is worldwide, the reason still could result from the introduction in this park. Common sense informs me that the condition of each area varies from each other. There cannot find an exactly common reason to explain whole phenomenon in the worldwide. Furthermore, how the author assures that the worldwide decline cannot attribute to the introduction of trout?

Moreover, even though the decline is not due to the introduction of trout, there still have many other possibilities to explain that reduce, but not the global pollution of water and air. It is possible, for instance, that the park has been repaired their pool during 77 years, and therefore, the decline lies in the amphibians cannot adapt this new circumstance. It is also possible that the tourists who visit the park throw food or rubbish into the pool, so that those junks gravely impact the ecological environment in the pool. Thus, the numbers of amphibians may also reduce.

Finally, even the author could substantiate all the flaws I have mentioned above, it also cannot prove that the worldwide decline only from a single park in California. After all, many factors could influence the numbers of amphibians. Whether the global pollution of water and air is in every area of having amphibians is uncharted.

In conclusion, the argument cannot be taken serious as it stands. To better evaluate it, the writer needs to support that the park is really polluted during those years and the introduction of trout really has no influence for the amphibians. Moreover, if the author desires to demonstrate a worldwide phenomenon, it must show more studies as much as he or she can.