Section II Reading Comprehension
Part A
Directions:
Read the following four texts. Answer the questions below each text by choosing [A]，[B]，[C] or [D]. Mark your answers on ANSWER SHEET 1. (40 points)
Text 1
Prudent investors learned long ago that putting your eggs into lots of baskets reduces risk. Conservationists have now hit on a similar idea: a population of endangered animals will have a better chance of survival if it is divided into interconnected groups. The prospects of the species will be better because the chance that all the constituent subpopulations will die out at the same time is low. And, in the long term, it matters little if one or two groups do disappear, because immigrants from better-faring patches will eventually reestablish the species' old haunts.
One endangered species divided in just this way is the world's rarest carnivore, the Ethiopian wolf, which lives high in the meadows of the Bale Mountains. Just 350 exist in three pockets of meadow connected by narrow' valleys in the Bale Mountains National Park, with a further 150 outside this area.
Two of the main threats to the Ethiopian wolf come from diseases carried by domestic dogs. One of these, rabies, is of particular concern because it is epidemic in the dog population. At first blush, vaccinating the wolves against rabies seems a simple solution. It would be ambitious, because the prevailing thinking — that all individuals matter and therefore all outbreaks of disease should be completely halted — implies that a large proportion of wolves would need to be vaccinated.
Dan Haydon, of the University of Glasgow, and his colleagues believe that conservation biologists should think differently. With the exception of humans, species are important but individuals are not. Some outbreaks of disease can be tolerated. In a paper published this week in Nature, they recast the mathematics of vaccination with this in mind.
On epidemiologists' standard assumption that every individual counts, vaccination programmes are intended to prevent epidemics by ensuring that each infected animal, on average, passes the disease on to less than one healthy animal. This implies that around two-thirds of all the wolves would need to be vaccinated. A programme that sought to save a species rather than individuals would allow each infected wolf to pass the disease on to more than one healthy animal and hence require fewer vaccinations. Dr Haydon and his colleagues have calculated, using data from a rabies outbreak in 2003, that vaccinating between 10% and 25% would suffice, provided veterinarians gave jabs to those wolves living in the narrow valleys that connect the subpopulations.
If the threat of rabies arose every five years, targeting all the wolves in the corridors would cut the risk of extinction over a 20-year period by fourfold. If this were backed up by vaccinating a mere 10% of the wolves in the three connected meadows, the chance of extinction would drop to less than one in 1,000. Saving a few seems to be an efficient way of protecting the many.
21. By citing prudent investors' idea, the author wants to illustrate that___________.
[A] conservationists got inspirations from it.
[B] endangered animals can be protected in a similar way.
[C] the prospects of some species depend on conservation.
[D] the subpopulations will die without being put into different groups.
22. The Ethiopian wolf___________.
[A] is facing the risk of extinction as the rarest carnivore.
[B] is separated into three groups to achieve survival.
[C] lives in narrow valleys in the Bale Mountains.
[D] has altogether 350 alive in the world.
23. The idea that nearly all the wolves would need to be vaccinated___________..
[A] is due to that rabies carried by dogs is epidemic.
[B] is very easy to be realized by local medical administration.
[C] is based on the thinking that every wolf is necessarily protected.
[D] is supported by Dan Haydon of the University of Glasgow.
24. From the last two paragraphs, we know that___________.
[A] if each individual counts, one-third of wolves have to be vaccinated.
[B] Dr. Haydon proved epidemiologists' standard assumption is right.
[C] to vaccinate 10% to 25% of wolves living in the connected meadows is enough.
[D] it takes 20 years to reduce risk of extinction if all the wolves are targeted.
25. The main purpose of the text is to___________.
[A] show the dangers Ethiopian wolves are facing with.
[B] inform people of the prospects Ethiopian wolves.
[C] teach how to divide Ethiopian wolves into groups.
[D] tell how to protect Ethiopian wolves from rabies.
考研课程试听
