【每日一題】AP 生物 20180124

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AP Biology精編

During the industrial revolution, a major change was observed in many insect species due to the mass production and deposition of ash and soot around cities and factories. One of the most famous instances was within the spotted moth populations. An ecological survey was performed where the number of spotted moths and longtail moths were counted in 8 different urban settings over a square kilometer in 1802. A repeat experiment was performed 100 years later in 1902. The results of the experiment are shown below.

What type of selection is represented by the results of this study?

(A) Stabilizing selection

(B) Directional selection

(C) Disruptive selection

(D) Divergent selection

題目解析

• Stabilizing selection 穩定選擇：針對某個特征的選擇，處于中間型的性狀被自然選擇保留，而處于兩端的性狀被淘汰，將降低遺傳多樣性
• Directional selection 定向選擇：生存環境的方向性選擇（自然選擇）或品種的人工定向選擇
• Disruptive selection 歧化選擇：針對某個特征的選擇，處于兩端的性狀被自然選擇保留，而處于中間型的性狀被淘汰，將增加遺傳多樣性
• Divergent selection 趨異選擇：由于共同祖先適應于不同環境，向兩個或者以上方向發展的過程。

數據顯示了原來的蛾子是白色為絕大多數，現在變成了黑色為絕大多數（由于城市污染等原因）。這是定向選擇的典型例子。正確答案(B) Directional selection。題目選自Cracking the AP Biology 2015 Edition