Intense natural selection caused a rapid morphological transition in a living marine snail.
Intense natural selection caused a rapid morphological transition in a living marine snail.
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强烈的自然选择导致活的海洋蜗牛发生快速的形态转变。
DOI：
10.1073/pnas.83.18.6897
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发表时间：
1986
影响因子：
11.1
通讯作者：
R. H. Seeley
中科院分区：
文献类型：
--
作者：
R. H. Seeley
1871 年至 1984 年间，新英格兰北部潮间带蜗牛 Littorina obtusata 的壳形状和壳厚度发生了显着变化。 1900 年之前收集的贝壳为高螺、薄壁，而 1982-84 年收集的贝壳为低螺、厚壁。一种以 L. obtusata 为食的潮间蟹 (Carcinus maenas) 在 1900 年左右将其活动范围扩大到新英格兰北部。这表明蜗牛壳形状的变化是对 Carcinus 捕食的反应。现场和实验室实验表明，在缅因州的一些地区仍然可以找到高螺旋的 L. obtusata，它比低螺旋的 L. obtusata 更容易受到 Carcinus 的捕食。 L. obtusata 的高螺和低螺种群的电泳比较证实，这些种群代表了 L. obtusata 的不同形态形式，而不是不同的物种 [Nei's D（遗传距离的无偏测量）= 0.003]。这些数据表明，经典达尔文选择可以产生快速的形态转变，而无需形成物种。
Shell shape and shell thickness of the intertidal snail Littorina obtusata changed markedly between 1871 and 1984 in northern New England. Shells collected prior to 1900 were high-spired with thin walls, whereas shells collected in 1982-84 were low-spired with thick walls. An intertidal crab (Carcinus maenas) which preys on L. obtusata expanded its range into northern New England around 1900. This suggests that the change in snail shell form was a response to predation by Carcinus. Field and laboratory experiments demonstrated that the high-spired form of L. obtusata, which can still be found in some Maine localities, is more vulnerable to predation by Carcinus than is the low-spired form of L. obtusata. Electrophoretic comparisons of high- and low-spired populations of L. obtusata confirmed that these populations represent different morphological forms of L. obtusata rather than different species [Nei's D (unbiased measure of genetic distance) = 0.003]. These data demonstrate that classical Darwinian selection can produce a rapid morphological transition without speciation.