[請益] TPO-31閱讀 #6

看板TOEFL_iBT (TOEFL_iBT托福)作者annieag (ㄚ君)時間11年前 (2014/11/27 14:35)推噓1(1推 0噓 8→)

留言9則, 3人參與討論串1/1

Geographic isolation also can proceedslowly, over great spans of time. We find evidence of such extended events in the fossil record, which affords glimpses into the breakup of formerly continuousenvironments. For example, during past ice ages, glaciers advanced down through North America and Europe and gradually cut off parts of populations from one another. When the glaciers retreated, the separated populations of plants and animals came into contact again. Some groups that had descended from the same parent population were no longer reproductively compatible— they had evolved into separate species. In other groups, however, genetic divergences had not proceeded so far, and the descendants could still interbreed— for them, reproductive isolation was not completed, and so speciation had not. 題目: Q6 According to paragraph 3, separation of subpopulations by glaciers resulted in speciation in those groups of plants and animals that A. were reproductively isolated even after the glaciers disappeared B. had adjusted to the old conditions caused by the glaciers C. were able to survive being separated from their parent population D. had experienced some genetic divergences from their parent population 解答給A 想請問一下為什麼不能選D 我的理解是冰河撤退後造成兩種group 一種:genetic divergence所以分離後的物種無法和另一物種reproductvely compatible 另一種:因reproductive isolation不完全所以一樣可interbreed A和D兩選項文章都有題及但為什麼答案是A 有請板上高手們幫忙解答謝謝! -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 114.44.71.237 ※ 文章網址: http://www.ptt.cc/bbs/TOEFL_iBT/M.1417070101.A.85C.html