The cheetah may be a gorgeous, sleek sports car among mammals, able to sprint at speeds approaching seventy miles an hour, yet it has not been able to run away from its many miseries. Once the cat ranged throughout the African
5 continent, the Near East, and into southern India; now it is extinct almost everywhere but in scattered patches of sub-Saharan Africa. Farmers in Namibia shoot cheetahs as vermin. On reserves, where cheetahs are often forced into unnatural proximity with other predators, they are at the
10 bottom of the meat eaters’ grim hierarchy; lions will go out of their way to destroy cheetah cubs, while hyenas, leopards, and even vultures can easily chase away a cheetah from its hard-caught prey. To make the magnificent cat’s story more poignant still, many scientists have concluded that the
15 species is severely inbred, the result of a disastrous population crash thousands of years ago from which the poor animals have hardly had a chance to recover.
Studies of cheetah chromosomes show a surprising lack of genetic diversity from one individual to the next, and as
20 a result the cheetah is widely portrayed as sitting under an evolutionary guillotine, the population so monochromatic that, in theory, a powerful epidemic could destroy many if not all of the approximately fifteen thousand cheetahs that currently exist in the wilderness.
25 Some zoos have complained that cheetahs are infertile, and they attribute the problem to the cheetah’s bleak genetic makeup, calling into question the long-term prognosis even for cats living in the pampered confines of a park. Now some maverick biologists argue that this widely held notion of
30 the inbred cheetah may be wrong, an artifact of test-tube manipulations with little relevance to the cat’s workaday world. They insist that, far from displaying the negative effects of lethargy and feebleness seen in other animals known to be genetically homogeneous, cheetahs are in
35 many ways quite robust.
The significance of the debate extends far beyond the cat itself. Scientists are seeking to calculate the odds that any number of endangered or threatened species are likely to survive into the twenty-first century, and among the many
40 questions they ask is how much genetic diversity a creature requires if it is to rebound from the brink of extinction. Inbreeding is thought to be harmful to a species for two reasons: first, it allows hazardous recessive traits to come to the fore, resulting in physical problems and, in some
45 cases, infertility; and second, it leads to a genetically uniform population without the diversity to resist epidemics and environmental changes.
But the scientists who resist the inbred cheetah dogma point out that many zoo cats bear healthy cubs, are
50 perfectly fertile and vigorous, and have great variation in their immune systems. While the cheetah may look genetically tenuous when its DNA is appraised, by such real-life measurements as litter size, cub health, and immune response, the cheetah is perfectly fit for the millennium. The work of
55 these scientists calls into question the validity of a strictly molecular approach to the sometimes murky science of species preservation, and it strongly suggests that scientists do not yet understand why certain genetic patterns detected in laboratory tests translate into the genuine strengths and
60 weaknesses of a wild animal. The work also indicates that zoos having trouble propagating cheetahs in captivity perhaps should not blame the animal’s DNA, but rather their own ineptitude at the science of animal breeding.
In the final analysis, the cheetah’s long-term future very
65 likely rests not on genetic research, but on old-fashioned remedies like preserving its remaining habitat and enlisting the help of those who live alongside it. In Namibia, where the cheetah does not have to compete with many other carnivores, as it does elsewhere in Africa, the feline fares
70 reasonably well, and its biggest problem is ranchers who shoot it in the belief that the cat threatens their livestock. Biologists in Namibia are seeking to convince the cattle owners that cheetahs in fact kill very few livestock animals, and to establish a compensatory program should
75 a calf occasionally be lost. With its sizeable free-ranging population now confined to Namibia, the cheetah is being pitched as a uniquely Namibian cat and thus a source of national pride. More than an ideal genetic profile, the cheetah needs a bit of panting room and all the public
80 relations its noble bearing can buy.
Ingore the numbers those are just the line numberings.
- The aspect of the “debate” (line 36) that the author is
most concerned with is
(A) the idealistic belief that something can still be
done to save endangered species from extinction
(B) the increasingly apparent differences in genetic
diversity between cheetahs and other mammals
(C) the acceptance of a species’ genetic profile as an
accurate indicator of its
chances for survival
(D) that scientists who argue against the inbreeding
theory offer no valid alternative explanations
for the cheetahs’ problems (E) that manipulating a species’ genetic makeup will yield unpredictable results and is potentially dangerous
I want to know why its not A. (the answer is c.)
- In line 80, “bearing” most nearly means (A) relationship or interconnection (B) the power of producing offspring (C) something that supports weight (D) demeanor or presence (E) awareness of a situation
The answer is D. Please explain why.
- In lines 54-63, the author’s discussion of the “science of species preservation” primarily suggests that (A) a focus on trivial details has sidetracked scientists from their chief aim (B) a sterile laboratory setting is an unlikely place to observe wild animals (C) genetic research is the key to enhancing a species’ ability to reproduce (D) scientists would be unwise to tamper with natural patterns of evolution (E) much remains to be learned about what factors determine a species’ survival
Why is it not B. the answer is E.