Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
PLoS One. 2012;7(5):e37069. doi: 10.1371/journal.pone.0037069. Epub 2012 May 14.
The origin of endothermy is a puzzling phenomenon in the evolution of vertebrates. To address this issue several explicative models have been proposed. The main models proposed for the origin of endothermy are the aerobic capacity, the thermoregulatory and the parental care models. Our main proposal is that to compare the alternative models, a critical aspect is to determine how strongly natural selection was influenced by body temperature, and basal and maximum metabolic rates during the evolution of endothermy. We evaluate these relationships in the context of three main hypotheses aimed at explaining the evolution of endothermy, namely the parental care hypothesis and two hypotheses related to the thermoregulatory model (thermogenic capacity and higher body temperature models). We used data on basal and maximum metabolic rates and body temperature from 17 rodent populations, and used intrinsic population growth rate (R(max)) as a global proxy of fitness. We found greater support for the thermogenic capacity model of the thermoregulatory model. In other words, greater thermogenic capacity is associated with increased fitness in rodent populations. To our knowledge, this is the first test of the fitness consequences of the thermoregulatory and parental care models for the origin of endothermy.
温血动物起源是脊椎动物进化中的一个令人费解的现象。为了解决这个问题，已经提出了几种解释模型。提出的温血动物起源的主要模型有氧能力、体温调节和亲代照顾模型。我们的主要建议是，要比较替代模型，一个关键的方面是确定在温血动物进化过程中，体温以及基础代谢率和最大代谢率对自然选择的影响有多大。我们在三个主要假说的背景下评估这些关系，这些假说旨在解释温血动物的进化，即亲代照顾假说和与体温调节模型（生热能力和更高体温模型）相关的两个假说。我们使用了 17 个啮齿动物种群的基础代谢率和最大代谢率以及体温数据，并使用内在种群增长率（R(max)）作为适应度的总体代理。我们发现，对体温调节模型中生热能力模型的支持更大。换句话说，在啮齿动物种群中，更大的生热能力与更高的适应度相关。据我们所知，这是对体温调节和亲代照顾模型对温血动物起源的适应后果的首次测试。
