0910G【Try Best】第二小组 argument207 by tianshi02

tianshi02UID: 2362794

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.
WORDS: 503          TIME: 00:40:00          DATE: 2009-7-11 12:17:57

In this argument, the arguer gives the facts that the Earth's ozone layer has thinned, and a species of salamander has declined in population. And then he/she unjustifiably concludes that the inceasing ultraviolet radiation caused by the damage of ozone layer hampers the hatching process of salamander and falsely generalize the reason for the declining population of other species.

First of all, it is too hasty for the arguer to ascribe the reason of the decline of the population of a species of salamander to the increasing level of ultraviolet radiation. It is said that ultraviolet radiation is known to be harmful to delicate issues. Even though salamander eggs have no protective shells, it may not follow that the eggs are delicate. It is very likely that these eggs have other protective mechanisms; for example, the protective membranes against ultraviolet radiation. In addition, even if it has a damaging effect on the eggs, we are convinced that they are damaged in such a way that hatching is thwarted. It may be the case that the damage is negligible.

Second, assuming ultraviolet radiation is indeed a reason for the declining population, we are not informed if there are other possible reasons, which play more essential roles on the shrinkage of population. Industrial pollution in recent years has also caused the severe water pollution and air pollution. It the salamander eggs are laid in the water, water pollution is certainly detrimental to the eggs. Moreover, the global temperature change is another factor that might affect the quality of eggs to be hatched. Besides, human exploitation of natural resources may have impaired the ecological system, which might affect the relationship of this kind of salamander with its preys and predators and thus its population. There are many other explanations for the deceasing population of the salamander. Without eliminating the part they play, it is presumptuous to say that ultraviolet radiation is the primary reason.

Lastly, the arguer asserts, without any supporting information,  that the cause of population declines in other species is the same as in salamander species. Even according to the ill-conceived reasoning of the arguer that the eggs without protective shells are delicate, one does not have to go very far to see that damage of ultraviolet radiation might not affect other species as seriously, since many species have eggs with shells. Besides, some other species may not even lay eggs, or they may lay their eggs deep in the water, where ultraviolet radiation is almost unreachable. It's also possible that the expanding predators lead to the declines of the population. Without accounting for such patent differences from the salamander species, any analogy is specious.

In sum, the argument is unconvincing as it stands. In order to strengthen the argument, the arguer would have to provide more facts, give more sound reasoning to show that ultraviolet radiation is one and a primary reason for the decline of salamander species. I personally think it would be very hard to argue that the decline of population of all other species is also due to ultraviolet radiaiton.