黑暗版阅读真题解析2006 Text 3
作者: 来源:沪江考研 时间:2007-12-04 16:40
2006 Text 3
When prehistoric man arrived in new parts of the world, something strange happened to the large animals. they suddenly became extinct. Smaller species survived. The large, slow-growing animals were easy game, and were quickly hunted to extinction.Now something similar could be happening in the oceans.
That the seas are being overfished has been known for years. What researchers such as Ransom Myers and Boris Worm have shown is just how fast things are changing. They have looked at half a century of data from fisheries around the world. Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time. According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) in a new fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then.
Dr. Worm acknowledges that these figures are conservative. One reason for this is that fishing technology has improved.Today's vessels can find their prey using satellites and sonar, which were not available 50 years ago. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes. In the early days, too, lonelines would have been more saturated with fish. Some individuals would therefore not have been caught, since no baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past. Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around now.
Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. They believe the date support an idea current among marine biologists, that of the "shifting baseline". The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past. That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels. Most fisheries are well below that, which is a bad way to be business.
31、The extinction of large prehistoric animals is noted to suggest that
A、large animal were vulnerable to the changing environment
B、small species survived as large animals disappeared
C、large sea animals may face the same threat today.
D、Slow-growing fish outlive fast-growing ones
32、We can infer form Dr. Myers and Dr. Worm's paper that
A、the stock of large predators in some old fisheries has reduced by 90%
B、there are only half as many fisheries are there were 15 years ago
C、the catch sizes in new fisheries are only 20% of the original amount
D、the number of larger predators dropped faster in new fisheries than in the old
33、By saying "these figures are conservative"(line 1 ,paragragf-3), Dr. worm means that
A、fishing technology has improved rapidly
B、the catch-sizes are actually smaller than recorded
C、the marine biomass has suffered a greater loss
D、the data collected so far are out of date.
34、Dr. Myers and other researchers hold that
A、people should look for a baseline that can‘t work for a longer time
B、fisheries should keep their yield below 50% of the biomass
C、the ocean biomass should be restored to its original level.
D、people should adjust the fishing baseline to the changing situation.
35、The author seems to be mainly concerned with most fisheries'
A、management efficiency
B、biomass level
C、catch-size limits
D、technological application.
猜你喜欢
- 出国留学中介前十名介绍 沪江是最好的选择
想要出国留学却没有时间没有精力去办理出国留学的手续,这个时候寻找一个好的出国留学中介就成了最好的办法,好的中介可以让自己更合理的去挑选自己喜欢的国家和学校,而且中介还有出国培训相关的内容,这...
- 日本动漫游戏:学校的圣域
feng社第9作第1弹《彼女のセイイキ(她的圣域)》,而系列的第2弹《妹的圣域》已于2015年08月28日发售,系列第3弹《学校的圣域》在2016年11月发售。
- 日本惊悚恐怖电影《裸体之夜:掠夺狂爱》
《裸体之夜2:掠夺狂爱》是由石井隆执导,竹中直人、佐藤宽子等领衔主演日本惊悚情色电影。该片讲述了主人公红次郎替年轻女孩加藤怜寻找叫“多绘”的救命恩人,结果踏入充满危机的“粉红”漩涡中。
- 秒变单身狗:哪些话不能对恋人说
恋爱初期总是美好而甜蜜的,然而两人长期处下来,就会发现对方的不足之处。生气起来口不择言,结果深深的伤害到两人的感情。这期给大家介绍一些对恋人可不能说的一些话。
- 「こんにちわ」是个啥?你知道吗?
常逛日站或是和日本朋友聊天的小伙伴们肯定经常会听到一句:こんにちわ,从发音上我们可以猜出来是こんにちは,但是这个こんにちわ是怎么来的呢?他又是什么呢?下面就让沪江日语教研君来告诉你吧!
- 日本礼仪:你真的会斟酒吗?
走进社会,我们不仅要在工作上努力努力再努力,还要一边学习一些社交礼仪。酒会作为一种常见的社交活动,学会其中的斟酒礼仪也是一门学问。今日,小编给大家整理了日本的斟酒礼仪供大家参考学习。
- 汉字词和成语 - 속담_뜻이 비슷한 속담
가재는 게와 생김새가 비슷하기 때문에 게 편을 든다는 말로, 서로 인연이 있는 것끼리 한편이 된다는 뜻이다. 비슷한 속담으로 '초록은 동색', … 가재는 게와 생김새가 비슷하기 때문에 게 ...