Limitations of Energy Acquisition and Energy Use in Small Poikilotherms: Evolutionary Implications
Limitations of Energy Acquisition and Energy Use in Small Poikilotherms: Evolutionary Implications
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小型异温动物能量获取和能量使用的局限性：进化意义
DOI：
10.2307/2389261
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发表时间：
1991
影响因子：
5.2
通讯作者：
W. Wieser
中科院分区：
文献类型：
--
作者：
W. Wieser
许多鱼是典型的“高风险物种”，在这种物种中，高繁殖产量抵消了幼鱼的高死亡率(或者，高死亡率是高繁殖产出的结果)。当仔鱼和幼鱼的死亡率达到9999%或更高时，即使是环境因素的随机波动也可能导致种群灭绝，从而决定区域渔业的命运(Sale，1990)。了解是什么使这些动物如此容易受到环境压力的影响，以及种群死亡曲线的形状如何对环境因素的强度和组合的微小变化做出反应，将具有相当大的实践和理论意义。在这里，我从最近关于鲤科幼体和幼体的能量学、发育和生理生态学的工作中解决这个问题，这项工作旨在阐明这个问题。根据形态和生理证据，我认为幼鱼孵化后面临的生态问题与小型后生动物的能量获取和能量使用等基本问题有关。假设有一种选择(如果有足够的遗传变异)倾向于增加动物体内的代谢能量流动，将动物从紧张的能量预算的限制中解放出来。在本次研讨会的框架内，令人感兴趣的是，Nellen(1986)根据生命周期理论提出了一个完全不同的假说来解释硬骨鱼的高繁殖力/死亡率。根据该作者的说法，在鱼类中的招募之所以如此之高，是因为幼虫作为亲代的食物，填补了第二消费者(原生动物、桡足类等)之间潜在猎物生物的大小差距。和第三产业生产者(鱼)。因此，“鱼的生长阶段似乎是生物结合能量沿着体重金字塔向上传递的理想有机体”(Nellen，1986，p.75)。这一理论带有一种群体选择主义的味道，看看它在理论家手中的表现将是有趣的，但毫无疑问，鱼类的高繁殖力和死亡率问题肯定既有生态方面的，也有生理方面的。
Many fish are typical 'high-risk species' in which a high reproductive output balances the high mortality of the young (or, alternatively, high mortality is the result of high reproductive output). When the mortality of larvae and juveniles reaches 99 99% or more, even stochastic fluctuations of environmental factors may drive populations to extinction and thus determine the fate of regional fisheries (Sale, 1990). It would be of considerable practical and theoretical interest to know what makes these animals so vulnerable to environmental pressure, and how the shapes of the mortality curves of populations might respond to even slight changes in the intensity and combination of environmental factors. Here, I address this question from recent work on the energetics, development, and physiological ecology of larval and juvenile cyprinids which was designed to shed some light on this question. On the basis of morphological and physiological evidence, I suggest that the ecological problems that young fish have to face after hatching are linked to fundamental problems of energy acquisition and energy use of small metazoans. A selection is postulated that would (if sufficient genetic variability were available) tend to increase the flow of metabolic energy through animals, liberating the animals from the constraints of tight energy budgeting. Within the framework of this symposium it is of interest that a completely different hypothesis for explaining the high fecundity/mortality of bony fish has been put forward by Nellen (1986), based on life-cycle theory. According to that author, recruitment in fish is so high because the larvae serve as food for the parental generation, filling the size gap of potential prey organisms between secondary consumers (protozoa, copepods, etc.) and tertiary producers (fish). Thus, 'growing life stages of fish appear to be ideal transfer organisms for biologically bound energy up the weight pyramid' (Nellen, 1986, p. 75). The theory has a group selectionist flavour and it will be interesting to see how it fares in the hands of theoreticians, but there can be no doubt that the problems of the high fecundity and mortality of fish must have both an ecological and a physiological aspect.