Adaptation and the cost of complexity
Adaptation and the cost of complexity
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DOI：
10.1111/j.0014-3820.2000.tb00002.x
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发表时间：
2000-02-01
期刊：
影响因子：
3.3
通讯作者：
Orr, HA
中科院分区：
文献类型：
--
作者：
Orr, HA
适应的特点是种群朝着多特征最佳状态移动，这种移动会导致适应性的增加。在这里，我计算了适应过程中适应度增加的速率，并描述了当种群接近费舍尔适应模型中的最佳值时适应度与时间的关系曲线。结果确定了影响适应速度的几个因素。最重要的因素之一是生物体的复杂性——当使用相同表型大小的突变时，复杂的生物体比简单的生物体适应得更慢。因此，正如费舍尔所预见的那样，生物体付出了一种复杂性的代价。然而，这一成本的规模远大于费舍尔的分析所暗示的。事实上，适应率的下降速度至少与 n(-1) 一样快，其中 n 是构成有机体的独立特征或维度的数量。目前的结果还表明，人们可以定义表征适应物种的有效维度数。
Adaptation is characterized by the movement of a population toward a many-character optimum, movement that results in an increase in fitness. Here I calculate the rate at which fitness increases during adaptation and describe the curve giving fitness versus time as a population approaches an optimum in Fisher's model of adaptation. The results identify several factors affecting the speed of adaptation. One of the most important is organismal complexity-complex organisms adapt more slowly than simple ones when using mutations of the same phenotypic size. Thus, as Fisher foresaw, organisms pay a kind of cost of complexity. However, the magnitude of this cost is considerably larger than Fisher's analysis suggested. Indeed the rate of adaptation declines at least as fast as n(-1), where n is the number of independent characters or dimensions comprising an organism. The present results also suggest that one can define an effective number of dimensions characterizing an adapting species.