問題詳情
Since the Hawaiian Islands have never been connected to other land masses, the greatvariety of plants in Hawaii must be a result of the long-distance dispersal of seeds, aprocess that requires both a method of transport and an equivalence between the ecology ofthe source area and that of the recipient area.There is some dispute about the method of transport involved. Some biologists arguethat ocean and air currents are responsible for the transport of plant seeds to Hawaii. Yetthe results of flotation experiments and the low temperature of air currents cast doubt onthese hypotheses. More probable is bird transport, either externally, by accidentalattachment of the seeds to feathers, or internally, by the swallowing of fruit and subsequentexcretion of the seeds. While it is likely that fewer varieties of plant seeds have reachedHawaii externally than internally, more varieties are known to be adapted to external than tointernal transport.
【題組】46. The author of the passage is primarily concerned with _______.
(A) discussing different theories about the transport of plant seeds toHawaii
(B) discussing the extent to which air currents are responsible for thedispersal of plant seeds to Hawaii
(C) resolving a dispute about the ability of birds to carry plant seedslong distances
(D) resolving a dispute about the adaptability of plant seeds to birdtransport
參考答案
答案：A
難度：適中0.681818
統計：A(45),B(8),C(6),D(7),E(0)
用户評論
【李明哲】評論
由於夏威夷群島從未被連接到其它陸地，在夏威夷種類繁多的植物必須是種子的長距離擴散，同時需要傳輸的方法和的生態之間等價的過程的結果源區和收件人區。有關於運輸所涉及的方法的一些爭議。一些生物學家認為，海洋和氣流負責植物種子運輸到夏威夷。然而的浮選試驗和空氣流的低溫的結果在這些假設產生懷疑。更有可能的是鳥類運輸：或者是通過外部，由種籽偶然粘附在羽毛，或內部，由水果和隨後將種籽排泄吞嚥。雖然這是可能的品種少的植物種子已經外部比內部達到夏威夷，多品種已知適於外部比內部運輸。