【每日一题】AP 生物 20180124

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AP Biology精编

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

题目解析

• Stabilizing selection 稳定选择：针对某个特征的选择，处于中间型的性状被自然选择保留，而处于两端的性状被淘汰，将降低遗传多样性
• Directional selection 定向选择：生存环境的方向性选择（自然选择）或品种的人工定向选择
• Disruptive selection 歧化选择：针对某个特征的选择，处于两端的性状被自然选择保留，而处于中间型的性状被淘汰，将增加遗传多样性
• Divergent selection 趋异选择：由于共同祖先适应于不同环境，向两个或者以上方向发展的过程。

数据显示了原来的蛾子是白色为绝大多数，现在变成了黑色为绝大多数（由于城市污染等原因）。这是定向选择的典型例子。正确答案(B) Directional selection。题目选自Cracking the AP Biology 2015 Edition