|
LZ 说的这个“一篇是讲毛毛虫，植物，还有捕捉一种毛毛虫的动物，这三者之间的关系，这篇是最长的”是不是就是GWD里的原文啊？！ A small number of the forest species of lepidoptera (moths and butterflies, which exist as caterpillars Line during most of their life cycle) exhibit (5) regularly recurring patterns of popu- 现象：毛虫有循环的数量变化 lation growth and decline—such 周期。究其原因 fluctuations in population are known as population cycles. Although many different variables influence popula- (10) tion levels, a regular pattern such as a population cycle seems to imply a dominant, driving force. Identification of that driving force, however, has 旧研究方法：不同捕食者造成 proved surprisingly elusive despite 的死亡率。-失败。 (15) considerable research. The com- mon approach of studying causes of population cycles by measuring the mortality caused by different agents, such as predatory birds or parasites, (20) has been unproductive in the case of lepidoptera. Moreover, population 旧研究方法：使毛虫搬家。 ecologists’ attempts to alter cycles -也失败。 by changing the caterpillars’ habitat and by reducing caterpillar popula- (25) tions have not succeeded. In short, the evidence implies that these insect populations, if not self-regulating, may 所以一定另有他因。 at least be regulated by an agent more intimately connected with the insect than (30) are predatory birds or parasites.老观点及其方法 Recent work suggests that this 近期研究发现根源是病毒。以前 agent may be a virus. For many 以为病毒只是推波助澜而非 years, viral disease had been 罪魁祸首。 reported in declining populations (35)
of caterpillars, but population ecolo- gists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it. The recent (40) work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environ- ment. Nuclear polyhedrosis viruses (45) are hypothesized to be the driving 病毒叫Np。它自身有一个感染 force behind population cycles in 周期。先是藏在蛋白质晶体里， lepidoptera in part because the 毛虫吃晶体，病毒释放，虫死， viruses themselves follow an infec- 大量有毒蛋白质晶体又产生并 tious cycle in which, if protected from 渗入大地。如此往复。 (50) direct sun light, they may remain virulent for many years in the envi- ronment, embedded in durable crystals of polyhedrin protein. Once ingested by a caterpillar, (55) the crystals dissolve, releasing the virus to infect the insect’s cells. Late in the course of the infection, millions of new virus particles are formed and enclosed in polyhedrin (60) crystals. These crystals reenter the environment after the insect dies and decomposes, thus becoming avail- able to infect other caterpillars.新观点及其论据 One of the attractions of this 支持病毒论，因为它适用于很多 (65) hypothesis is its broad applicability. 情况。 Remarkably, despite significant differ- ences in habitat and behavior, many species of lepidoptera have population cycles of similar length, between eight (70) and eleven years. Nuclear polyhe- drosis viral infection is one factor these disparate species share.新观点正评价 老新观点 1P: population cycle, identify driving force, however, surprising elusive. Common approach unproductive; ecologist’s attempt, not succeed. In short, population regulated by intimated connected with insects. 2P: recent work suggest virus. Contributed to. Recent work made possible by new techniques. NP hypothesized because… 3P: attractions of hypothesis is …. -------------------------------------------------------------------------------- GWD-13-Q34: Which of the following, if true, would most weaken the author’s conclusion in lines 25-30? A. New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.支持 B. New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles. In short,
the evidence implies that these insect
populations, if not self-regulating, may
at least be regulated by an agent more
intimately connected with the insect than
are predatory birds or parasites. C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.支持 D. Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles. E. Viral disease is typically observed in a large proportion of the lepidoptera population.支持 -------------------------------------------------------------------------------- GWD-13-Q35: It can be inferred from the passage that the mortality caused by agents such as predatory birds or parasites was measured in an attempt to A. develop an explanation for the existence of lepidoptera population cycles The common approach of studying causes of
population cycles by measuring the mortality caused by different agents,
such as predatory birds or parasites,
has been unproductive in the case of
lepidoptera. B. identify behavioral factors in lepidoptera that affect survival rates C. identify possible methods for controlling lepidoptera population growth偏 D. provide evidence that lepidoptera populations are self-regulating E. determine the life stages of lepidoptera at which mortality rates are highest -------------------------------------------------------------------------------- GWD-13-Q36: The primary purpose of the passage is to - describe the development of new techniques that may help to determine the driving force behind population cycles in Lepidoptera新观点中有阐述但不是文章主旨
- present evidence that refutes a particular theory about the driving force behind population cycles in Lepidoptera不是文章重心
- present a hypothesis about the driving force behind population cycles in Lepidoptera
- describe the fluctuating patterns of population cycles in Lepidoptera
- question the idea that a single driving force is behind population cycles in lepidoptera
-------------------------------------------------------------------------------- GWD-13-Q37: According to the passage, before the discovery of new techniques for detecting viral DNA, population ecologists believed that viral diseases
A. were not widely prevalent among insect populations generally B. affected only the caterpillar life stage of Lepidoptera C. were the driving force behind lepidoptera population cycles D. attacked already declining caterpillar populations For many
years, viral disease had been
reported in declining populations of
caterpillars, but population ecologists had usually considered viral
disease to have contributed to the
decline once it was underway
rather
than to have initiated it. E. infected birds and parasites that prey on various species of lepidoptera ------------------------------------------------------------------------------------------------------------ | 
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2009-3-3 18:07:00
楼主