SAT阅读话题分类——生物环境

      That large animals require a luxuriant vegetation, has
　　been a general assumption which has passed from
　　one work to another; but I do not hesitate to say that
　　it is completely false, and that it has vitiated the
　　5 reasoning of geologists on some points of great
　　interest in the ancient history of the world. The
　　prejudice has probably been derived from India, and
　　the Indian islands, where troops of elephants, noble
　　forests, and impenetrable jungles, are associated
　　10 together in every one's mind. If, however, we refer to
　　any work of travels through the southern parts of
　　Africa, we shall find allusions in almost every page
　　either to the desert character of the country, or to the
　　numbers of large animals inhabiting it. The same
　　15 thing is rendered evident by the many engravings
　　which have been published of various parts of the
　　interior.
　　Dr. Andrew Smith, who has lately succeeded in
　　passing the Tropic of Capricorn, informs me that,
　　20 taking into consideration the whole of the southern
　　part of Africa, there can be no doubt of its being a
　　sterile country. On the southern coasts there are some
　　fine forests, but with these exceptions, the traveller
　　may pass for days together through open plains,
　　25 covered by a poor and scanty vegetation. Now, if we
　　look to the animals inhabiting these wide plains, we
　　shall find their numbers extraordinarily great, and
　　their bulk immense. We must enumerate the elephant,
　　three species of rhinoceros, the hippopotamus, the
　　30 giraffe, the bos caffer, two zebras, two gnus, and
　　several antelopes even larger than these latter
　　animals. It may be supposed that although the species
　　are numerous, the individuals of each kind are few.
　　By the kindness of Dr. Smith, I am enabled to show
　　35 that the case is very different. He informs me, that in
　　lat. 24', in one day's march with the bullock-wagons,
　　he saw, without wandering to any great distance on
　　either side, between one hundred and one hundred
　　and fifty rhinoceroses - the same day he saw several
　　40 herds of giraffes, amounting together to nearly a
　　hundred. At the distance of a little more than one
　　hour's march from their place of encampment on the
　　previous night, his party actually killed at one spot
　　eight hippopotamuses, and saw many more. In this
　　45 same river there were likewise crocodiles. Of course
　　it was a case quite extraordinary, to see so many great
　　animals crowded together, but it evidently proves that
　　they must exist in great numbers. Dr. Smith describes
　　the country passed through that day, as 'being thinly
　　50 covered with grass, and bushes about four feet high,
　　and still more thinly with mimosa-trees.'
　　Besides these large animals, every one the least
　　acquainted with the natural history of the Cape, has
　　read of the herds of antelopes, which can be
　　55 compared only with the flocks of migratory birds.
　　The numbers indeed of the lion, panther, and hyena,
　　and the multitude of birds of prey, plainly speak of
　　the abundance of the smaller quadrupeds: one
　　evening seven lions were counted at the same time
　　60 prowling round Dr. Smith's encampment. As this able
　　naturalist remarked to me, the carnage each day in
　　Southern Africa must indeed he terrific! I confess it is
　　truly surprising how such a number of animals can
　　find support in a country producing so little food. The
　　65 larger quadrupeds no doubt roam over wide tracts in
　　search of it; and their food chiefly consists of
　　underwood, which probably contains much nutriment
　　in a small bulk. Dr. Smith also informs me that the
　　vegetation has a rapid growth; no sooner is a part
　　70 consumed, than its place is supplied by a fresh stock.
　　There can be no doubt, however, that our ideas
　　respecting the apparent amount of food necessary for
　　the support of large quadrupeds are much
　　exaggerated.
　　75 The belief that where large quadrupeds exist, the
　　vegetation must necessarily be luxuriant, is the more
　　remarkable, because the converse is far from true. Mr.
　　Burchell observed to me that when entering Brazil,
　　nothing struck him more forcibly than the splendour of
　　80 the South American vegetation contrasted with that of
　　South Africa, together with the absence of all large
　　quadrupeds. In his Travels, he has suggested that the
　　comparison of the respective weights (if there were
　　sufficient data) of an equal number of the largest
　　85 herbivorous quadrupeds of each country would be
　　extremely curious. If we take on the one side, the
　　elephants hippopotamus, giraffe, bos caffer, elan,five
　　species of rhinoceros; and on the American side, two
　　tapirs, the guanaco, three deer, the vicuna, peccari,
　　90 capybara (after which we must choose from the
　　monkeys to complete the number), and then place
　　these two groups alongside each other it is not easy to
　　conceive ranks more disproportionate in size. After the
　　above facts, we are compelled to conclude, against
　　95 anterior probability, that among the mammalia there
　　exists no close relation between the bulk of the
　　species, and the quantity of the vegetation, in the
　　countries which they inhabit.

1. The author is primarily concerned with
　　A. discussing the relationship between the size of mammals and the nature of vegetation in their habitats
　　B. contrasting ecological conditions in India and Africa
　　C. proving the large animals do not require much food
　　D. describing the size of animals in various parts of the world
　　E. explaining that the reasoning of some geologists is completely false

　　2. The word ‘vitiated’ (line 4) most nearly means
　　A. infiltrated
　　B. occupied
　　C. impaired
　　D. invigorated
　　E. strengthened

　　3. According to the author, the ‘prejudice’ (line 7) has lead to
　　A. errors in the reasoning of biologists
　　B. false ideas about animals in Africa
　　C. incorrect assumptions on the part of geologists
　　D. doubt in the mind of the author
　　E. confusion in natural history

　　4. The author uses information provided by Dr. Smith to
　　I supply information on quality and quantity of plant life in South Africa
　　II indicate the presence of large numbers of animals
　　III give evidence of numbers of carnivorous animals
　　A. I only
　　B. II only
　　C. III only
　　D. I and II only
　　E. I, II and III

　　5. The flocks of migratory birds (line 55)are mentioned to
　　A. describe an aspect of the fauna of South Africa
　　B. illustrate a possible source of food for large carnivores
　　C. contrast with the habits of the antelope
　　D. suggest the size of antelope herds
　　E. indicate the abundance of wildlife

　　6. The ‘carnage’ (line 61) refers to the
　　A. number of animals killed by hunters
　　B. number of prey animals killed by predators
　　C. number of people killed by lions
　　D. amount of food eaten by all species
　　E. damage caused by large animals

　　7. To account for the ‘surprising’ (line 63) number of animals in a ‘country producing so little food’ (line 64), Darwin suggests all of the following as partial explanations except
　　A. food which is a concentrated source of nutrients
　　B. rapid regrowth of plant material
　　C. large area for animals to forage in
　　D. mainly carnivorous animals
　　E. food requirements have been overestimated

　　8. The author makes his point by reference to all of the following except
　　A. travel books
　　B. published illustrations
　　C. private communications
　　D. recorded observations
　　E. historical documents

　　9. Darwin quotes Burchell’s observations in order to
　　A. counter a popular misconception
　　B. describe a region of great splendor
　　C. prove a hypothesis
　　D. illustrate a well-known phenomenon
　　E. account for a curious situation

　　10. Darwin apparently regards Dr. Smith as
　　A. reliable and imaginative
　　B. intrepid and competent
　　C. observant and excitable
　　D. foolhardy and tiresome
　　E. incontrovertible and peerless

　　11. Darwin’s parenthetical remark (line 83-84) indicates that
　　A. Burchell’s data are not reliable
　　B. Burchell’s ideas are not to be given much weight
　　C. comparison of the weights of herbivores is largely speculative
　　D. Darwin’s views differ from Burchell’s
　　E. more figures are needed before any comparison can be attempted

　　12. Anterior probability (line 95) refers to
　　A. what might have been expected
　　B. ideas of earlier explorers
　　C. likelihood based on data from India
　　D. hypotheses of other scientists
　　E. former information

查看正确答案和解析

• 有疑问在线咨询老师

  咨询时间:9:00-23:00
  非咨询时间也可留言

• 400-618-0271

  咨询时间:
  9:00-23:00