飞蛾和蝴蝶题

xjtufu

43.   GWD-13-Q34 -Q37是谁控制着毛毛虫的生命长度

     A small number of theforest

      species of lepidoptera(moths and

      butterflies, which exist ascaterpillars

Line during most of their lifecycle) exhibit

 (5)       regularly recurring patterns of popu-

lation growth and decline—such

fluctuations in population are known

as population cycles.  Althoughmany

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

proved surprisingly elusive despite

(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

      ecologists’ attempts toalter cycles

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

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 thatthis

agent may be a virus.  For many

      years, viral disease hadbeen

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.  Therecent

(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 polyhedrosisviruses

(45)       are hypothesized to be the driving

force behind population cycles in

lepidoptera in part because the

viruses themselves follow an infec-

tious cycle in which, if protected from

(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.  Thesecrystals 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 ofthis

(65)       hypothesis is its broad applicability.

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.

题目基本相同，可能有变体

T-9-20:GWD-13-34:
Which of the following, if true, would most weaken the author’s conclusion inlines 25-30?
A.    New research reveals that the number of species of birdsand parasites that prey on lepidoptera has dropped significantly in recentyears.
B.    Newexperiments in which the habitats of lepidoptera are altered in previouslyuntried ways result in the shortening of lepidoptera population cycles.
C.    Recent experiments have revealed that the nuclearpolyhedrosis virus is present in a number of predators and parasites oflepidoptera.
D.    Differences among the habitats of lepidoptera species makeit difficult to assess the effects of weather on lepidoptera population cycles.
E.    Viral disease is typically observed in a large proportionof the lepidoptera population.
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T-9-21:GWD-13-35:
It can be inferred from the passage that the mortality caused by agents such aspredatory birds or parasites was measured in an attempt to
       
A.    developan explanation for the existence of lepidoptera population cycles
B.    identify behavioral factors in lepidoptera that affectsurvival rates
C.    identify possible methods for controlling lepidopterapopulation growth
D.    provide evidence that lepidoptera populations areself-regulating
E.    determine the life stages of lepidoptera at which mortalityrates are highest
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T-9-22:GWD-13-36:
The primary purpose of the passage is to
       
A.    describe the development of new techniques that may helpto determine the driving force behind population cycles in Lepidoptera
B.    present evidence that refutes a particular theory aboutthe driving force behind population cycles in Lepidoptera
C.    presenta hypothesis about the driving force behind population cycles in Lepidoptera


D.    describe the fluctuating patterns of population cycles inLepidoptera
E.    question the idea that a single driving force is behindpopulation cycles in Lepidoptera

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T-9-23:GWD-13-37:
According to the passage, before the discovery of new techniques for detectingviral DNA, population ecologists believed that viral diseases
A.    were not widely prevalent among insect populationsgenerally
B.    affected only the caterpillar life stage of lepidoptera
C.    were the driving force behind lepidoptera populationcycles
D.    attackedalready declining caterpillar populations
E.    infected birds and parasites that prey on various speciesof Lepidoptera

by fydaydayup (700，Q51，V32)一种飞蛾，他们的数量有周期性的变化。但是一开始，科学家用常规的方法都没有测量出来引起周期性变化的原因，既不是生存地的条件，也不是捕食者的数量。后来科技发展，科学家发现应该是一种病毒。这个病毒会保存在一种晶体里面，晶体被飞蛾吃掉后，外壳就融化，然后病毒在飞蛾体内繁殖，同时包裹上晶体，等飞蛾死掉，那些晶体就落在土壤里了。然后这个发现很有意义，因为很多别的种类的飞蛾也可能是这个原因

cuiyinggrace

期待新jj出炉

hhmia

顶~

顶一个

这是今天的题吗?

fay1127

这么说GWD一定都要做一遍啦~

bblythe

顶啦！！谢谢~

Bale

怎么负责整理的筒子都没收录这些考古

angxiaoang

为什么看GWD的答案是CDEA