[a习作temp] argument45 [直接冲刺小组]第十三次作业 [复制链接]

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电梯直达

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发表于 2007-7-28 23:20:12 |只看该作者 |倒序浏览

TOPIC: ARGUMENT45 - The following appeared as an editorial in a wildlife journal.

"Arctic deer live on islands in Canada's arctic region. They search for food by moving over ice from island to island during the course of a year. Their habitat is limited to areas warm enough to sustain the plants on which they feed, and cold enough, at least some of the year, for the ice to cover the sea separating the islands, allowing the deer to travel over it. Unfortunately, according to reports from local hunters, the deer populations are declining. Since these reports coincide with recent global warming trends that have caused the sea ice to melt, we can conclude that the decline in arctic deer populations is the result of deer being unable to follow their age-old migration patterns across the frozen sea."

By citing the local hunters' report that the deer populations are decrease and the fact that this event happened along with the global warming trend, the speaker assume that the change of the frozen sea which was used to be the migration patterns account for the decline in arctic deer populations. This argument seems reasonable at first sight, however, a closer examination found that there are some logical flaws in it.

To begin with, the local hunters' report is not objective and thus it can not represent the real change of deer population. Since the hunter feels the declining of deer population by their observie when hunting, it is entirely possible the deer are much more guard than before and thus whenever the hunter invade their areas they may go to other areas to hide. Also, perhaps the deer may have changed their habitat for a long time while the hunter does not find out. Then, the deer will appear less in their usual habitat and were less hunted by people. Either this scenario, if ture, the speaker can not state that the population of deer are decreasing.

Even if the deer population are decreasing, the speaker's conclusion is unwarranted. On the one hand, Since the speaker provide no real evidence to support the globla warming trends has influenced the deer's migration patterns, he can not assume that the deer's age-old migration patterns have changed by the global warming trends. On the other hand, even if the global warming trends have changed their age-old migration patterns, the speaker can not assume that this change account for the decline in arctic deer populations. There is no evidence that their age-old migration patterns still play important role in arcitc deer's life. Perhaps they have found new ways to migrate according to the global climate change. Or perhaps they no longer migrate anymore for the global warming increased their food supply in the island in winter. If these cases are true, then the decline of deer population can not be account for the global warming caused age-old migration patterns' change.

Even if the disappear of age-oldmigration patterns plays a role in the decline of arctic deer, the speaker can not exclude other factors that play a much more important role in this delcine. Perhaps, the hunting is the main reason that caused the decreasing of deer population. Or perhaps the predator population of the deer are increasing dramatically these years. Either case, if ture, the speaker's conclusion is unconving.

To sum up, the speaker should provide more evidence to bloster this argument. For example he should provide evidence that the old-age migration pattern has changed by global warming trends, and also he should prove that thses patterns still plays an important role in the deer's life. In addition, he should exclude other possible explanations for this decline.