TPO 34综合写作阅读材料 与范文

TPO 34 综合写作

Reading

A huge marine mammal known as Steller’s sea cow once lived in the waters around Bering Island off the coast of Siberia. It was described in 1741 by Georg W. Steller, a naturalist who was among the first European to see one. In 1768 the animal became extinct. The reasons for the extinction are not clear. Here are three theories about the main cause of the extinction.

First, the sea cows may have been overhunted by groups of native Siberian people. If this theory is correct, then the sea cow population would have originally been quite large, but hundreds of years off too much hunting by the native people diminished the number of sea cows. Sea cows were a good source of food in a harsh environment, so overhunting by native people could have been the main cause of extinction.

Second, the sea cow population may have become extinct because of ecosystems disturbances that caused a decline in their main source of food, kelp (a type of sea plant). Kelp populations respond negatively to a number of ecological changes. It is possible that ecological changes near Bering island some time before 1768 caused a decrease of the kelp that the sea cows depend on.

Third, the main cause of extinction of the sea cows could have been European fur traders who came to the island after 1741. It is recorded that the fur traders caught the last sea cow in 1768. It thus seems reasonable to believe that hunting by European fur traders, who possessed weapons that allowed them to quickly kill a large number of t he animals, was the main cause of the sea cow’s extinction.

Sample Answer

According to the reading passage, the author claims that there are three theories elaborating the reasons for the decline of sea cows. However, the lecturer entirely challenges these theories.

First of all, in the reading passage the author believes that overhunting by Siberian for food is the major factor for the decrease of sea cows. In contrast, the lecturer opposes this view and maintains that sea cows, a kind of animal with approximately ten tons, are too enormous for people to eat, and another point refuting the view in the reading is that the population of people was not substantial at that time, which do not have the capacity to kill the majority of sea cows.

Furthermore, the reading passage maintains that the extinction of sea cows is due to the fact that the quantity of Kelp, regarded as the food resource of sea cows, is decreased by the destruction of ecosystem. On the contrary, the lecturer asserts that Kelp also is the food resource for whales, which means if the population of Kelp decreases, the number of whales will decline as sea cows do. But there is no report about the decline of them.

Eventually, the lecturer casts doubt on the point made by the author that the extinction of sea cows may be caused by European fur traders, and he proposes that actually when European fur traders firstly arrived there, the population of sea cows had already been small; therefore, there must be other fatal events causing the decrease in the population of sea cows before fur traders being there.

1