Argument150 by rodgood两栖动物的减少与污染 谢谢，请留下您的链接，一定回拍

rodgoodUID: 2619326

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."


In this letter, the writer attributes the decline in the number of amphibians to the water and air pollution worldwide. Two studies, indicating the decrease of amphibians’ number in 77 years in Yosemite National Park (YNP), are cited to justify the conclusion. Although the evidence looks cogent and the reasoning seems logical, close scrutiny reveals that both of them suffer flaws that mislead the editor of the magazine.

To begin with, it is a little haste to rule out the factor of trout to the decrease of amphibians in YNP. As mentioned in the letter, "trout are known to eat amphibians eggs," which is fatal to A's propagation. Furthermore, ecological knowledge informs us that an abrupt invasion of a species to a region would influence others' regular life there. The introduction of trout would probably affect the food chain in the YNP that also leads to the Y decline. So, without any concrete reason, denying the effect of trout is irresponsible.

In addition, even granted that trout cannot be the real reason for Y decline as the arguer says, there is little information that is helpful in making the supposition that the reason is pollution. Apart from trout, other factors would also cause the result, climate for example. During 77 years between the two studies, the atmosphere temperature might have changed to some extent. As we all known that amphibian is cold-blooded animal whose body temperature depends mostly on environment, so when the temperature outside changes, their lives would be influenced, which may bring about their decline. Therefore, pollution is not the reason leading to the amphibians decline in YNP unless more supportive evidence is presented.

Finally, even though pollution is the factor causing the decline of amphibians in YNP, no available evidence is offered to prove pollution's effect on the decline on the planet. The writer makes an overgeneralization concerning the problem. There may be many other factors resulting in the tragedies. Hunting, for example, cannot be overlooked since countless animals are killed by people every year. What's more, it is also highly possible that some amphibians are not able to survive because of their inner reasons such as mutation. In general, the arguer is supposed to present more information demonstrating that the worldwide decline of amphibians is because of pollution.

In sum, the author looks anxious to figure out the causes of the decline of amphibians, failing to launch more investigation and analysis that are important in obtaining right answers. Unless more cogent information is presented, the conclusion cannot be made. Otherwise, more extinction of amphibians is possibly followed if impropriate measures are carried out.