Argument91
Threeyears ago, because of flooding at the Western Palean Wildlife Preserve, 100lions and 100 western gazelles were moved to the East Palean Preserve, an areathat is home to most of the same species that are found in the westernpreserve, though in larger numbers, and to the eastern gazelle, a closerelative of the western gazelle. The only difference in climate is that theeastern preserve typically has slightly less rainfall. Unfortunately, afterthree years in the eastern preserve, the imported western gazelle populationhas been virtually eliminated. Since the slight reduction in rainfall cannot bethe cause of the virtual elimination of western gazelle, their disappearancemust have been caused by the larger number of predators in the easternpreserve.
The argument introduces the fact that 100 western gazelles were moved to the East Palean Preserve because of a recent flooding but they soon disappeared in the eastern preserve, and then the arguer concludes that such a diminishing is due the larger number of predators in this area. To substantiate this view, the speaker cites the similarity of climate between the two regions to exclude the possible impact brought by climate. Further, he claims that because the slight differences in rain fall could be ignored, predators must be the determining factor for the extinction. However, the whole argument is filled with holes, and the arguer should re-think his view with more logical consideration.
To begin with, the argument does not convince us that the rain fall, or water supply cannot be a vital cause for the elimination of western gazelle. From the passage, we can only know that the amount of water supply between eastern and western areas is close to each other. However, we have no idea on the specific water demand on the western preserve because the arguer totally overlooks such a crucial factor. If the number of native animals in the western area is far more than that in the east, water resources would be extremely demanding for the settlers in this area. As a result, even a slight reduction may lead to water shortage, especially for herbivorous animals which are not so aggressive. Moreover, if the completion for water in the western area is so fierce, while in the eastern preserves animals do not to care about such a problem, it is very likely that these newly comers from the east could be competed enough to survive here. Therefore, unless we obtain sufficient evidence to show the water demand between the two areas could match with each other, the potential effect of the different in climate should not be simply excluded.
Moreover, even if we can assure that the change in climate is negligible, it goes too far to assert that the predator causes the elimination. For one thing, the speaker fails to offer us any information about the predator, and therefore, we are even not sure whether these predators are exist in the western area, or could become a serious threat. If the population of herbivorous is the mainstream in the western, such a conclusion would naturally be belied. For another, there are many alternative explanations for the above phenomenon, but the speaker ignores them intentionally or unintentionally. As an illustration, the immigrating population of eastern gazelles may at degenerating stage, and most of the group members are too old to get through such a immigration. Besides, these gazelles may suffer from a prevalent but fatal disease, but we just do not know. In that case, the speaker must conduct investigation on how these gazelles eliminates, and provide reliable information to prove that the predators in this area are indeed a threat for gazelles.
Taking all factors into consideration, we could see that the credibility of the passage is vulnerable from the lack of essential evidences and logical links. A careful analysis of all the factors mentioned above is necessary for the author to double-consider the case, and make a convincible for explanation for the real cause of the gazelle’s elimination
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