argument 84, 求狠拍

zhanghaolin

84. The following is a letter to the editor of an environmental magazine.

"Two studies of amphibians in Xanadu National Park confirm a significant decline in the numbers of amphibians. In 1975 there were seven species of amphibians in the park, and there were abundant numbers of each species. However, in 2002 only four species of amphibians were observed in the park, and the numbers of each species were drastically reduced. One proposed explanation is that the decline was caused by the introduction of trout into the park's waters, which began in 1975. (Trout are known to eat amphibian eggs.)"

Write a response in which you discuss one or more alternative explanations that could rival the proposed explanation and explain how your explanation(s) can plausibly account for the facts presented in the argument.

In the letter, one proposed explanation to the reduction of amphibians is that the decline was caused by the introduction of trout into the park's waters, which began in 1975. The author cites the following as evidence: both the number of species and individuals were drastically reduced from 1975 to 2002 while the trout has been introduced since 1975. The argument seems to be well-presented and reasonable at first glance; however, I am afraid it can hardly bear further consideration because there might be other explanations to the facts provided.

First and foremost, the author only mentions that only four species of amphibians were observed in the park in 2002 but provide no information to substantiate whether the other species are extinct or not. As we know, even though many kinds of animals are not migrating animals, they can still change their location of inhabiting because of the change of climate or environment. It is possible that because the introduction of trout, some species of amphibians gradually leave the places they lived in and move to a more suitable place where there have less natural enemies. To answer whether the species of amphibian still exist or not, the author should collect more data about the observational reports in and near the national park.

Furthermore, the author makes a precipitous assumption that the reduction of amphibians are caused by trout without providing convincible evidence. There are no such reports to illustrate how damage the trout has done to the amphibians. It is possible that even though the trout were deadly threat to amphibians' eggs at first time, during a long period of time, the amphibians have already adjusted such threat and found out effective methods to keep their population steady, which is hardly surprising in the natural world. The author needs to provide data scientific experiments or observations to find out the actuality.

Last but not the least; the author apparently does not take account of some other possible factors in existence which can also influence the survival of amphibians. These factors include something such as change of climate (the change of the climate might trigger the chain effect that cause the extinction of the plants or small animals which are the food of those amphibians), pollution level (the pollution from the industries makes the harmful chemical substance accumulate in the body of amphibians though water or food chains) or the human factors. The author should take such factors into consideration in order to avoid an incomplete conclusion.

To sum up, after pointing out so many obvious flaws in the argument, we can say that the evidence cited by author to support the argument can hardly be relied on. Before reaching a final conclusion, the author should make comprehensive investigation on the situation of survival of amphibians in the park and rule out the influence of other factors such as environmental change, pollution level and change of climate.

普渡哥

First and foremost, the author only mentions that only four species of amphibians were observed in the park in 2002 but provide no information to substantiate whether the other species are extinct or not.

provide要+s吧。