[u'r not alone小组]提纲作业 Argument45

Luise8891UID: 2906459

:p 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."

dreamerdanceUID: 2759402

1. 得出论断的前提是鹿的数目的确在下降。但是论者仅用当地猎人的报告，不足以证明。因为很有可能猎人只是因为打不到鹿，而认为鹿数目在下降。但是这些猎人活动的时间、范围以及习惯是否与鹿相同都会影响到他们是否能看见鹿。

2．即使鹿群数量的确在下降，论断的另一个前提也不一定成立。前提是当地的气温的确在上升。但全球势趋不能代表本地状况，很有可能全球某些地方气温升高很快，使得全球气温上升，但本地的气温仍可能不变，甚至下降。但是论者没有提供任何资料证明当地的气温比以前高了。

3． 即使升高了，但是论者没有提供任何资料证明如果气温上升，环境改变，鹿就会死亡。气温上升或许会使鹿生存的环境发生变化，它们的活动模式或许必需有所改变，但这些都不必造成鹿死亡。

。•论者的结论很武断。他认为是气温上升改变了鹿的迁徒模式，而不是其他原因导致鹿数目下降。但是显然猎人是否有过度猎杀、鹿的某种食物最近是不是大面积减少等等都能使得鹿数目下降。结论：论者若要增加说服力，还因提供目前鹿数目的变化情况，以及当地气温是否有上升。另外鹿的生存环境是否还存在其他的威胁也需要调查。

tingsnowyUID: 2739192

1. the hunters, referred by the arguer, is of highest probability to contribute to the decline in deer population.
2. the remains of deer have not been found larger than before, thus the population is not necessarily on declining. The mass deer maybe confined in one large island where there is enough food for them to live by, so there is less chance for hunters to see them.
3. the world-wide warming does not mean that the temperature is unable to freeze the water on the sea and form the pass for the deer to walk.