新gre逻辑阅读 每日一练2

　　新gre考试实施以来，参加了新版gre考试的考生都觉得阅读部分的题难度增加了，这主要是由于新gre考试逻辑阅读需要考生的逻辑反应一定要比以前更快，可能考生还是有点不习惯，或是没有准备充足。那么，接下来的几天，小编将给大家搜索整理一些新gre考试逻辑阅读的练习题，希望考生能从平日的练习中总结规律，找到解题技巧。

　　Many theories have been formulated to explain the

　　role of grazers such as zooplankton in controlling the

　　amount of planktonic algae in lakes.

　　The first theories of such grazer control were merely

　　5 based on observations of negative correlations

　　between algal and zooplankton numbers. A low number

　　of algal cells in the presence of a high number of

　　grazers suggested, but did not prove, that the grazers

　　had removed most of the algae. The converse obser-

　　10 vation, of the absence of grazers in areas of high

　　phytoplankton concentration, led Hardy to propose

　　his principle of animal exclusion, which hypothe-

　　sized that phytoplankton produced a repellent that

　　excluded grazers from regions of high phytoplankton

　　15 concentration. This was the first suggestion of algal

　　defenses against grazing.获得更多gre考试咨询点击进入免费咨询顾问或联系QQ客服：800004500

　　Perhaps the fact that many of these first studies

　　considered only algae of a size that could be collected

　　in a net , a practice that over-

　　20 looked the smaller phytoplankton

　　that we now know grazers are most likely to feed on,

　　led to a de-emphasis of the role of grazers in subse-

　　quent research. Increasingly, as in the individual

　　studies of Lund, Round, and Reynolds, researchers

　　25 began to stress the importance of environmental

　　factors such as temperature, light, and water move-

　　ments in controlling algal numbers. These environ-

　　mental factors were amenable to field monitoring and

　　to simulation in the laboratory. Grazing was believed

　　30 to have some effect on algal numbers, especially after

　　phytoplankton growth rates declined at the end of

　　bloom periods, but grazing was considered a minor

　　component of models that predicted algal population

　　dynamics.

　　35 The potential magnitude of grazing pressure on

　　freshwater phytoplankton has only recently been

　　determined empirically. Studies by Hargrave and

　　Geen estimated natural community grazing rates by

　　measuring feeding rates of individual zooplankton

　　40 species in the laboratory and then computing com-

　　munity grazing rates for field conditions using the

　　known population density of grazers. The high esti-

　　mates of grazing pressure postulated by these

　　researchers were not fully accepted, however, until the

　　45 grazing rates of zooplankton were determined directly

　　in the field, by means of new experimental techniques.

　　Using a specially prepared feeding chamber, Haney

　　was able to record zooplankton grazing rates in natural

　　field conditions. In the periods of peak zooplankton

　　50 abundance, that is, in the late spring and in the summer,

　　Haney recorded maximum daily community grazing rates,

　　for nutrient-poor lakes and bog lakes, respectively, of 6.6

　　percent and 114 percent of daily phytoplankton production.

　　Cladocerans had higher grazing rates than

　　55 copepods, usually accounting for 80 percent of the

　　community grazing rate. These rates varied seasonally,

　　reaching the lowest point in the winter and early spring.

　　Haneys thorough research provides convincing field

　　evidence that grazers can exert significant pressure on

　　60 phytoplankton population.

　　

　　1. It can be inferred from the passage that the first　theories of

　　grazer control mentioned in the first paragraph would have been

　　more convincing if researchers had been able to

　　 observe high phytoplankton numbers under

　　natural lake conditions

　　 discover negative correlations between

　　algae and zooplankton numbers from their

　　field research

　　 understand the central importance of

　　environmental factors in controlling the

　　growth rates of phytoplankton

　　 make verifiable correlations of cause and

　　effect between zooplankton and

　　phytoplankton numbers

　　 invent laboratory techniques that would

　　have allowed them to bypass their field

　　research concerning grazer control

　　2. Which of the following, if true, would call into

　　question Hardys principle of animal exclusion?

　　 Zooplankton are not the only organisms

　　that are affected by phytoplankton

　　repellents.

　　 Zooplankton exclusion is unrelated to

　　phytoplankton population density.

　　 Zooplankton population density is higher

　　during some parts of the year than during

　　others.

　　 Net phytoplankton are more likely to

　　exclude zooplankton than are

　　nannoplankton.

　　 Phytoplankton numbers can be strongly

　　affected by environmental factors.

　　For the following question, consider each of the choices separately and select all that apply

　　3. The author would be likely to agree with

　　which of the following statements regarding

　　the pressure of grazers on phytoplankton

　　numbers?

　　□A Grazing pressure can vary according to the

　　individual type of zooplankton.

　　□B Grazing pressure can be lower in nutrient-poor lakes

　　than in bog lakes.

　　□C Grazing tends to exert about the same

　　pressure as does temperature.

　　4. It can be inferred from the passage that one way

　　in which many of the early researchers on grazer

　　control could have improved their data would

　　have been to

　　 emphasize the effects of temperature, rather

　　than of light, on phytoplankton

　　 disregard nannoplankton in their analysis of

　　phytoplankton numbers

　　 collect phytoplankton of all sizes before

　　analyzing the extent of phytoplankton

　　concentration

　　 recognize that phytoplankton other than net

　　phytoplankton could be collected in a net

　　 understand the crucial significance of net

　　phytoplankton in the diet of zooplankton

　　5. According to the passage, Hargrave and Geen

　　did which of the following in their experiments?

　　 They compared the grazing rates of

　　individual zooplankton species in the

　　laboratory with the natural grazing rates

　　of these species.

　　 The hypothesized about the population

　　density of grazers in natural habitats by

　　using data concerning the population

　　density of grazers in the laboratory.

　　 They estimated the community grazing rates

　　of zooplankton in the laboratory by using

　　data concerning the natural community

　　grazing rates of zooplankton.

　　 They estimated the natural community

　　grazing rates of zooplankton by using

　　data concerning the known population

　　density of phytoplankton.

　　 They estimated the natural community

　　grazing rates of zooplankton by using

　　laboratory data concerning the grazing

　　rates of individual zooplankton species.

　　答案：　D/B/AB/C/E

　　以上即是阅读练习题，对于新gre考试逻辑阅读，考生除了采取题海战术，其实更应该做的就是总结。如果能从平日的练习中找到解新gre考试逻辑阅读题的思路，那么，要比采取题海战术更好。