Type: 長篇/自然科學類/新舊觀點陳述/作者認同新觀點
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【原文】
A small number of the forest species of lepidoptera (moths and butterflies, which exist as caterpillars during most of their life cycle) exhibit regularly recurring patterns of population growth and decline—such fluctuations in population are known as population cycles. Although many different variables influence population 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 considerable research. 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. Moreover, population ecologists’ attempts to alter cycles by changing the caterpillars’ habitat and by reducing caterpillar (25) populations 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 are predatory birds or parasites. (30)
Recent work suggests that this agent may be a virus. 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. The recent work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environment. Nuclear polyhedrosis viruses are hypothesized to be the driving force behind population cycles in lepidoptera in part because the viruses themselves follow an infectious cycle in which, if protected from direct sun light, they may remain virulent for many years in the environment, embedded in durable crystals of polyhedrin protein. Once ingested by a caterpillar, 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 polyhedron crystals. These crystals reenter the environment after the insect dies and decomposes, thus becoming available to infect other caterpillars.
One of the attractions of this hypothesis is its broad applicability. Remarkably, despite significant differences in habitat and behavior, many species of lepidoptera have population cycles of similar length, between eight and eleven years. Nuclear polyhedrosis viral infection is one factor these disparate species share.
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【題目】
T-9-21:GWD-13-34:
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.
B. New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
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.
T-9-21:GWD-13-35:
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
B. identify behavioral factors in lepidoptera that affect survival rates
C. identify possible methods for controlling lepidoptera population growth
D. provide evidence that lepidoptera populations are self-regulating
E. determine the life stages of lepidoptera at which mortality rates are highest
T-9-22:GWD-13-36:
The primary purpose of the passage is to
A. describe the development of new techniques that may help to
B. determine the driving force behind population cycles in Lepidoptera
C. present evidence that refutes a particular theory about the driving force behind population cycles in Lepidoptera
D. present a hypothesis about the driving force behind population cycles in Lepidoptera
E. describe the fluctuating patterns of population cycles in Lepidoptera
question the idea that a single driving force is behind population cycles in Lepidoptera
T-9-23:GWD-13-37:
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
E. infected birds and parasites that prey on various species of lepidoptera
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Para 1: 毛毛蟲的數量變化，有一個規律的週期性，雖然目前的研究數量已經很多，但對於影響毛毛蟲數量的因子卻還是難以捉摸；常見的影響因子如掠食者、寄生蟲(parasites)都被證明是無關的。此外，population ecologists想要透過改變棲息地或減少毛毛蟲數量來影響群體數量的實驗也都失敗了，總的來說，這些昆蟲的數量如果不是自律的，那麼最少會受制於一個比寄生蟲或掠食者更直接影響的因素。
Para 2: 近年來的研究顯示，影響數量的因子可能是病毒；這是一種population ecologists過去認為有助於減少數量，而不是造成數量減少因子的假說。舉例: 新型病毒Nuclear polyhedrosis 在陽光下不會發病，但隱藏在毛毛蟲體內，最後在沒有陽光的時候一發不可收拾。
Para 3: (點出作者preference) One of the “attractions” of this hypothesis是可以廣泛的應用，即使行為及棲息地的不同，不同品種的毛毛蟲還是有著相同的數量週期，而感染新型病毒Nuclear polyhedrosis是這些品種共有的特徵。
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>Q34 CR Weaken題
題目要打臉” 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.”
>這些昆蟲的數量如果不是自律的，那麼最少會受制於一個比寄生蟲或掠食者更直接影響的因素 (或劃線句前面提到的靠著改變棲息地或是減少毛毛蟲數量也無效)
高分詳解裡面的是用
定位句” Moreover, population ecologists’ attempts to alter cycles by changing the caterpillars’ habitat and by reducing caterpillar populations have not succeeded.”選到正確答案B的，提供給大家參考。
我是用刪去法得到答案的，因為跟病毒有關的理論都間接證明/支持了上面這個論點，所以CE刪掉，D的difficult to assess推不出，A的敘述無關，所以最後選到證明棲息地改變會有效影響數量的(B)選項。但這一題花了2:05..
有強者願意分享一下自己的解題點嘛?
>Q35 Infer題
定位句” 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.”
第一遍掃下來刪掉了選項中沒有population關鍵字的(B)(E)；而(D)的self-regulating離題
剩下AC二選一，然後選錯了，徵求強者分享一下別的解題點
事後諸葛知道定位句中的unproductive跟C選項中的possible methods有衝突，所以這是A選項比較優秀的地方。
不過還是想聽聽其他人的想法!
>Q36 Main Idea題
貫穿第二三段的”Hypothesis”漂亮出現在C選項中，加上最後一段第一句One of the attractions of this hypothesis is its broad applicability作者陳述一個Hypothesis優勢，所以選C
(A) development of new techniques
(B) refutes a particular theory
(C) 正確答案
(D) fluctuating patterns
(E) question the idea
>Q37 Detail題 關鍵字:Beofre
定位句” 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.”
因為population ecologists認為病毒只是contributed to the decline而不是to have initiated it.
(D) already attacked 呼應題目的before也呼應定位句裡的initiated.
其他選項裡面都跟時間點”Before”沒關係，定位好10秒就賭了，事後諸葛其他選項內容不是無關就是時間點不對，若有刪不掉的提出來我們一起討論^^
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