argument207 小鸡快跑第一次作业

tina2010UID: 2240650

第一次写，感觉废话太多，希望大家猛拍~

TOPIC: ARGUMENT207 - It is known that in recent years, industrial pollution has caused the Earth's ozone layer to thin, allowing an increase in the amount of ultraviolet radiation that reaches the Earth's surface. At the same time, scientists have discovered, the population of a species of salamander that lays its eggs in mountain lakes has declined. Since ultraviolet radiation is known to be damaging to delicate tissues and since salamander eggs have no protective shells, it must be the case that the increase in ultraviolet radiation has damaged many salamander eggs and prevented them from hatching. This process will no doubt cause population declines in other species, just as it has in the salamander species.

In this argument, the arguer concludes that the increase in ultraviolet radiation (UR) is the cause of the population decline of salamander. And the arguer assumes that the same problem will exist in other species just as in the salamander. This conclusion is based on the observation that scientists have discovered the population of a species of salamander that lays its eggs in mountain lakes has declined. A careful scrutiny of this argument would reveal how groundless it is.

First, the author unfairly assumes that the increase in ultraviolet radiation bears definite relation to the population decline of salamander. This assumption comes from the discovery of those scientists who found out that the population of a species of salamander that lays its eggs in mountain lakes has declined. However, the arguer provides no evidence that this is the case, nor does the arguer establish a causal relationship between ultraviolet radiation and population decline of salamander. It is highly possible that other factors might contribute to the decline. For example, it is also likely the decline just resulted from the environment change, such as climate, soil, water, or the advent of new predator which can decrease the number of female salamander sharply. Lacking evidence that links the increase in UR to the decline of salamander, it is presumptuous to suggest that the increase in UR was responsible for the decline.

Second, although it is known that UR can damage delicate tissue, such as salamander eggs which have no protective shells, the author can not simply draws the conclusion that the increase in UR has damaged many salamander eggs and prevented them from hatching by his/her imagination. Maybe the increase in UR just contributes to the aberrance of those salamander eggs, rather than damaging them and preventing them from hatching. In fact, in face of such unwarranted reasoning, it is fallacious to draw any conclusion at all. Unless it can be shown that the increase in UR is the only reason that causes the decline, the conclusion that the decline is caused by the increase of UR is completely unwarranted.

Last but not the least, even if the increase in UR is the reason which resulted in the population decline of salamander, the author can not simply assumes that it will cause population decline in other species. As we know, different species differ conspicuously. The population of one species depends on many factors, such as climate, food, the type and number of predators, and migration, etc. As a result, salamander and other species do not establish a warranted analogy, so we can not safely assume that.

In summary, this argument is not persuasive as it stands. Before we accept the conclusion, the arguer must present more facts to demonstrate that the increase in UR is responsible for the population decline of salamander and other species. To solidify the argument, the arguer would have to provide enough evidence to rule out other possible causes of the decline.

[ 本帖最后由 tina2010 于 2007-2-21 23:54 编辑 ]

xrsdbUID: 2222298

灰常不错啊，都挑不出什么毛病了
就是那个食肉动物使得雌性蜥蜴数目下降的举例有点怪。雌性不用写么吧？

tina2010UID: 2240650

呵呵，谢谢xrsdb
那个想法是突然灵光一现出来的，现在看来觉得可以不用特别指明是雌的哦，呵呵，当时主要是脑子里老在想egg,egg,egg,所以就写了female.
再次感谢:loveliness: