Direction：

Arctic deer live on islands in Canada's arctic regions. They search for food by moving over ice from island to island during the course of the 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 purported decline in deer populations is the result of the deer's being unable to follow their age-old migration patterns across the frozen sea.

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.

題目講解：

Arctic deer live on islands in Canada's arctic regions. They search for food by moving over ice from island to island during the course of the 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 purported decline in deer populations is the result of the deer's being unable to follow their age-old migration patterns across the frozen sea.

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.

題目講解

【翻譯】

北極鹿生活在加拿大極地區域的島嶼上。它們全年都通過冰塊在島嶼間移動來尋找食物。它們的棲居地局限在那些溫暖得足以維持它們所需的植物生長，并且在一年的至少某些時候冷到足以讓島嶼間的海面結冰以使它們能夠在島嶼間旅行的地方。然而，根據當地獵人的報告，鹿的數量正在下降。由于這一報告正好與最近導致海洋冰面融化的全球變暖趨勢同時發生，我們可以得出結論：北極鹿數量的下降是它們無法按它們原有的遷移習慣穿越結冰海面的結果。

【分析】

1.沒有證據表明warming trend已經導致北極鹿無法像祖先一樣在冰塊上遷徙

2.也沒有證據顯示馴鹿的數量減少和全球氣候變暖有關

3.其他因素：本地獵人的報告是否準確;沒有說明，如果北極鹿不能夠遷徙就會死亡或者減少

【提綱】

1report。

2同時發生不說明有因果關系(concurrence)。全球趨勢不說明地方。

3即使鹿的數量下降了，也有可能其他因素：基因因素、環境污染、溫度下降食物減少。