Institute of Biology, University of Kassel, Kassel, Germany.
Plant Biol (Stuttg). 2015 Jan;17 Suppl 1:24-32. doi: 10.1111/plb.12171. Epub 2014 Mar 26.
In evolutionary biology, the term 'Darwinian fitness' refers to the lifetime reproductive success of an individual within a population of conspecifics. The idea of a 'Darwinian Demon' emerged from this concept and is defined here as an organism that commences reproduction almost immediately after birth, has a maximum fitness, and lives forever. It has been argued that duckweeds (sub-family Lemnoideae, order Alismatales), a group containing five genera and 34 species of small aquatic monocotyledonous plants with a reduced body plan, can be interpreted as examples of 'Darwinian Demons'. Here we focus on the species Spirodela polyrhiza (Great duckweed) and show that these miniaturised aquatic angiosperms display features that fit the definition of the hypothetical organism that we will call a 'Darwin-Wallace Demon' in recognition of the duel proponents of evolution by natural selection. A quantitative analysis (log-log bivariate plot of annual growth in dry biomass versus standing dry body mass of various green algae and land plants) revealed that duckweeds are thus far the most rapidly growing angiosperms in proportion to their body mass. In light of this finding, we discuss the disposable soma and metabolic optimising theories, summarise evidence for and against the proposition that the Lemnoideae (family Araceae) reflect an example of reductive evolution, and argue that, under real-world conditions (environmental constraints and other limitations), 'Darwin-Wallace Demons' cannot exist, although the concept remains useful in much the same way that the Hardy-Weinberg law does.
在进化生物学中，“达尔文适合度”一词是指个体在同种群体中的终生繁殖成功率。“达尔文恶魔”这个概念由此产生，这里将其定义为一种在出生后几乎立即开始繁殖、具有最大适合度且长生不老的生物体。有人认为，浮萍科（Lemnoideae 亚科，泽泻目），一组包含 5 属 34 种小型水生单子叶植物，具有简化的身体结构，可以被解释为“达尔文恶魔”的例子。在这里，我们专注于浮萍物种 Spirodela polyrhiza（大浮萍），并表明这些微型水生被子植物具有符合我们称之为“达尔文-华莱士恶魔”的假设生物体的特征，以纪念自然选择进化的两位主要支持者。定量分析（各种绿藻和陆生植物的年干生物量增长与干体质量比值的对数-对数双变量图）表明，浮萍是迄今为止按体重比例增长最快的被子植物。鉴于这一发现，我们讨论了可丢弃体细胞和代谢优化理论，总结了支持和反对浮萍科（天南星科）反映简化进化例子的证据，并认为，在现实世界的条件下（环境限制和其他限制），“达尔文-华莱士恶魔”不可能存在，尽管该概念仍然有用，就像 Hardy-Weinberg 定律一样。
