The planet’s wild creatures face a new threat from yuppies, empty nesters, singletons and one parent families. Biologists studyi

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问题     The planet’s wild creatures face a new threat from yuppies, empty nesters, singletons and one parent families. Biologists studying the pressure on the planet’s dwindling biodiversity today report on a new reason for alarm. Although the rate of growth in the human population is decreasing, the number of individual households is exploding. Even where populations have actually dwindled—in some regions of New Zealand, for instance—the number of individual households has increased, because of divorce, career choice, smaller families and longer lifespans.
    Jianguo Liu of Michigan State University and colleagues from Stanford University in California re port in Nature, in a paper published online in advance, that a greater number of individual house holds, each containing on average fewer people, meant more pressure on natural resources. Towns and cities began to sprawl as new homes were built. Each household needed fuel to heat and light it; each household required its own plumbing, cooking and refrigeration. "In larger households, the efficiency of resource consumption will be a lot higher, because more people share things," Dr. Liu said. He and his colleagues looked at the population patterns of life in 141 countries, including 76 "hotspot" regions unusually rich in a variety of endemic wildlife. These hot spots included Australia, New Zealand, the US, Brazil, China, India, Kenya, and Italy. They found that between 1985 and 2000 in the "hotspot" parts of the globe, the annual 3.1% growth rate in the number of households was far higher than the population growth rate of 1.8 %.
    "Had the average household size remained at the 1985 level," the scientists report, "there would have been 155m fewer households in hotspot countries in 2000. Paradoxically, smaller households do not mean smaller homes. In Indian River County, Florida, the average area of a one-storey, single family house increased 33 % in the past three decades."
    Dr. Liu’s work grew from the alarming discovery that the giant pandas living in China’s Wolong reserve were more at risk now than they were when the reserve was first established. The local population had grown, but the total number of homes had increased more swiftly, to make greater inroads into the bamboo forests.
    Gretchen Daily of Stanford, one of the authors, said: "We all depend on open space and wild places, not just for peace of mind but for vital services such as crop pollination, water purification and climate stabilization. The alarming thing about this study is the finding that, if family groups continue to become smaller and smaller, we might continue losing biodiversity—even if we get the aggregate human population size stabilised."

选项 A、the amount of wildlife is diminishing.
B、the population of human is decreasing.
C、New Zealanders live an unstable life.
D、the structure of families is changing.

答案D

解析 本题问第一段主要告诉我们什么。第一段主要谈论"虽然人口的增长放慢,但家庭的总数却在激增。即使在人口减少的地区也是如此"。其原因之一是"smaller families",即家庭变小了,也就是说家庭的结构变了。因此,"家庭结构正在改变"正确。野生动植物总量正在减少:本文所说的生物多样性的减少是物种的减少而不是总量的减少,况且这也不是第一段的重点。人口总数正在减少:第一段第三句提到"the rate of growth in the human population is decreasing",增长率在降低,只是说增长速度放慢,但人口的数量仍然在增加。而且在首段讨论的不是人口的数量问题,而是家庭的数量问题。新西兰人的生活不稳定:文中只作为例证提到新西兰某些地区人口减少,并没有说生活不稳定。
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