【Big Fish】3月26号 Argument207 by 星

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Based on the fact that a species of salamander declined while the amount of ultraviolet radiation was increasing, the author claims that it is no doubt that other species will also decline. Careful examination of this supporting evidence, however, reveals that it lends little credible support to the author’s claim.

A threshold assumption upon which the claim relies is that the whole salamander species ‘（？）reduction occurred in the first place. The argument fails to substantiate this crucial assumption. It is mentioned in the argument that one species of salamander that lays its eggs in the mountain lake declined. However, it was only carried out in this species， the author applies its result to all species of salamander while not showing us whether this species is representative of the overall species of salamander. It is entirely possible that the other species increase. For that matter, perhaps the total numbers of the salamander on versa enhance. Therefore, without ruling out those possibilities, the author‘s conclusion that the population decline in the salamander species is untenable.

Even assuming that the total numbers of the salamander decline, the additional assumption that the reductions are due to the increasing amount of the ultraviolet radiation lends no significant support to the claim. It is true that the ultraviolet radiation has a chilling effect on the salamander’s eggs, however, there may be other factors that could be instead responsible for the salamander’s reductions. Such factors might be that the environment of the mountain lake changed for some reasons and was not suitable for the salamander’s survive. It is equally possible that the salamander’s eggs were eaten by another animal—which was a freshman in the mountain lake. Hence, lacking sufficient evidence to demonstrate those factors, the author can not draw a firm conclusion that ultraviolet radiation attributes to the salamander’s reductions.

Even assuming that the ultraviolet radiation causes the whole species of salamander’s diminution, the author’s assumption that all species in the world will decline is doubtful. The argument mentions that not having protective shells leads the ultraviolet radiation to damage the salamander’s eggs. Nevertheless, as we know, every species on the earth is different. Do all the species’ eggs in the world not have protective shells? （The answer is ） Definitely not. It might be tempting to agree that the ultraviolet radiation has no harmful effect on the species owning dear protective shells. In sum, since the author has not adequately responded to this concern, his claim is greatly unconvincing.

To wrap up, the author’s claim is unpersuasive as it stands, to make it logically acceptable, the author need to provide clear evidence that the whole species of salamander decline and not some other factors, are responsible for the salamander’s diminution. To better evaluate the claim, the author must demonstrate that the ultraviolet radiation damages all species no matter owning protective shells or not.

让步是好用，但是所有中国学生都这么用就不好了，试试新的方法。
同时，有的太口语的要改改。
每一段的论证还是挺清楚地
加油：）