Official 47 Passage 2


Termite Ingenuity


According to paragraph 5, what does the thinness of the ridge walls make possible?

Click on an oval to select your answer. To choose a different answer,

click one different oval.

  • A
    The concentration of cool air in the cellar
  • B
    The construction of exceptionally long tunnels
  • C
    The even distribution of oxygen from attic to cellar
  • D
    The diffusion of gases into and out of the ridges
正确答案: D

我的笔记 编辑笔记

  • 原文
  • 译文
  • Termites, social insects which live in colonies that, in some species, contain 2 million individuals or more, are often incorrectly referred to as white ants. But they are certainly not ants. Termites, unlike ants, have gradual metarnorphosis with only three life stage: egg, nymph, and adult. Ants and the other social members of their order, certain bees and wasps, have complete metarnorphosis in four life stages; egg, larva, pupa, and adult. The worker and soldier castes of social ants, bees, and wasps consist of only females, all daughters of a single queen that mated soon after she matured and thereafter never mated again. The worker and soldier castes of termites consist of both males and females, and the queen lives permanently with a male consort.

    Since termites are small and soft-bodied, they easily become desiccated and must live in moist places with a high relative humidity. They do best when the relative humidity in their nest is above 96 percent and the temperature is fairly high, an optimum of about 79°F for temperate zone species and about 86°F for tropical species. Subterranean termites, the destructive species that occurs commonly throughout the eastern United States, attain these conditions by nesting in moist soil that is in contact with wood, their only food. The surrounding soil keeps the nest moist and tends to keep the temperature at a more or less favorable level. When it is cold in winter, subterranean termites move to burrows below the frost line.

    Some tropical termites are more ingenious engineers, constructing huge above-ground nests with built-in "air conditioning" that keeps the nest moist, at a constant temperature, and well supplied with oxygen. Among the most architecturally advanced of these termites is an African species, Macroternes natalensis. Renowned Swiss entomologist Martin Luscher described the mounds of this fungus-growing species as being as much as 16 feet tall, 16 feet in diameter at their base, and with a cement-like wall of soil mixed with termite saliva that is from 16 to 23 inches thick. The thick and dense wall of the mound insulates the interior microclimate from the variations in humidity and temperature of the outside atmosphere. Several narrow and relatively thin-walled ridges on the outside of the mound extend from near its base almost to its top.

    According to Luscher, a medium-sized nest of Macrotermes has a population of about 2 million individuals. The metabolism of so many termites and of the fungus that they grow in their gardens as food helps keep the interior of the nest warm and supplies some moisture to the air in the nest. The termites saturate the atmosphere of the nest, bringing it to about 100 percent relative humidity, by carrying water up from the soil.

    But how is this well-insulated nest ventilated? Its many occupants require over 250 quarts of oxygen (more than 1,200 quarts of air ) per day. How can so much oxygen diffuse through the thick walls of the mound? Even the pores in the wall are filled with water, which almost stops the diffusion of gases. The answer lies in the construction of the nest. The interior consists of a large central core in which the fungus is grown, below it is "cellar" of empty space, above it is an "attic" of empty space, and within the ridges on the outer wall of the nest, there are many small tunnels that connect the cellar and the attic. The warm air in the fungus gardens rises through the nest up to the attic. From the attic, the air passes into the tunnels in the ridges and flows back down to the cellar. Gases, mainly oxygen coming in and carbon dioxide going out, easily diffuse into or out of the ridges, since their walls are thin and their surface area is large because they protrude far out from the wall of the mound. Thus air that flows down into the cellar through the ridges is relatively rich in oxygen, and has lost much of its carbon dioxide. It supplies the nest`s inhabitants with fresh oxygen as it rises through the fungus-growing area back up to the attic.

  • 白蚁是群居昆虫,有些种类的白蚁会生活在包含200万个或更多个体的群体中,他们通常被错误地称为白蚁。但它们肯定不是蚂蚁。白蚁,不像蚂蚁,它的渐变态只有三个生活期:卵、幼虫、成虫。蚂蚁和其他同种类的群居虫类(某些蜜蜂和黄蜂),有着四个生命阶段的完全变态,卵、幼虫、蛹和成虫。群居蚂蚁、蜜蜂和黄蜂的职蚁和兵蚁的构成中都只有雌性,一个女王所有的女儿在成年后马上交配,并且在那以后不会再次交配。白蚁的职蚁和兵蚁既有雄性也有雌性,并且女王将永远和一个雄性配偶生活在一起。




  • 官方解析
  • 网友贡献解析
  • 标签
    14 感谢 不懂


    选项分析:题干问:根据第五段,墙体薄的地方可以使……变成可能?从原文 Gases easily diffuse into or out of the ridges, since their walls are thin …,可知,墙体薄的地方是为了让气体进入和排出。因此选项D符合。