Three years ago, because of flooding at the Western Palean Wildlife Preserve, 100 lions and 100 western gazelles were moved to the East Palean Preserve, an area that is home to most of the same species that are found in the western preserve, though in larger numbers, and to the eastern gazelle, a close relative of the western gazelle. The only difference in climate is that the eastern preserve typically has slightly less rainfall. Unfortunately, after three years in the eastern preserve, the imported western gazelle population has been virtually eliminated. Since the slight reduction in rainfall cannot be the cause of the virtual elimination of western gazelle, their disappearance must have been caused by the larger number of predators in the eastern preserve.

Write a response in which you discuss what specific evidence is needed to evaluate the argument and explain how the evidence would weaken or strengthen the argument.

The author of the statement presents the fact that western gazelles, which were transferred to East Palean Preserve from Western Palean Wildlife Preserve, has been nearly eliminated. Acknowledging the slight difference in the amount of rainfall in the two preserves, the author concludes that such elimination was due to the larger number of predators in the eastern preserve. Although in reality predators may be the culprit here, this is not a conclusion that can be safely arrived at given the amount of information offered by the author. It is possible that the elimination was caused by other factors and more evidence is needed to determine what the true cause(s) is/are.

In the first place, although the author claims that the slight reduction in rainfall cannot be the cause of the virtual elimination of western gazelle, we still need more evidence to evaluate this claim. Built upon this conclusion is the assumption that such a slight decrease of rainfall in the East Preserve will not make much change on western gazelles’ lives, but no supporting evidence is presented. It may be the case that the decrease of rainfall caused the availability of drinking water in East Palean Preserve to decline and subsequently led to the drinking difficulty for western gazelles. To solve this uncertain question, a detailed report of western gazelles’ living habits are highly desirable. The author’s recommendation will be bolstered if the report shows western gazelles does not need frequent water drinking and their living habits are not depended on rainfall. In contrast, if the report shows that western gazelles’ survival rate is extremely sensitive to water availability, it is less logically sound to exclude the reduction in rainfall from the causes of elimination, and the author’s argument would be weakened.

Additionally, the elimination of western gazelles might be caused by other natural factors rather than climate factors. For example, the competition between eastern and western gazelles might be the trigger of the elimination for western gazelles. It is possible that western gazelles are less competitive than eastern gazelles and they fail to obtain enough food as a result. In order to clarify the validity for such suggestion, one simple test is to investigate the status of eastern gazelles. On one hand, if eastern gazelles not only survived but also thrived in spite of the fate of western gazelle, the elimination might be caused by the failure of competing for more food resource. The author’s line of reasoning will be less logical. On the other hand, the author’s conclusion will be more valid if both the population of eastern and western gazelles experienced the significant decline.

Lastly, in addition to natural factors, human factors are also plausible causes for the elimination for western gazelles. A reasonable and intuitive candidate for such factors could be the inhumane killings by poachers. If western gazelles’ value is high in the market, it is possible that poachers would try to kill them for higher profits. When western gazelles were in West Palean Preserve, poachers might be strictly monitored so there are few killing. East Palean Preserve, by contrast, might be less strict with poachers so more western gazelles are being killed by them. In this case, we need to investigate the remains of the western gazelles that was killed in the preserve. A natural wound such as biting or tearing wounds would strengthen the conclusion of the author, while a shotgun hole or steel trap would make the author less logical.

To sum up, while it may be logical to conclude that western gazelles’ elimination was connected to the increase of number of predators, the author does not present convincing evidence to eliminate other possible factors. We need more information to make a rational judgment on whether predators are the main reason that cause the elimination for western gazelles.

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