Modelling growth, vital statistics and energy budget of sauropods: key features contributing to gigantism.

不同年龄和大小的死亡率和繁殖力在物种之间表现出相当大的差异。它们反映了生命周期的特征(例如性成熟时的年龄、寿命)，决定了人口统计(例如内在增长率、世代时间)和人口的重要统计数据。繁殖力和体型的增长是联系在一起的，因为有机体的能量吸收是有限的。身体的大小也与死亡率和维持生物体所需的能量吸收比例有关。在这里，我们将通过应用不同的建模方法来建立蜥脚类动物的特定年龄和大小的死亡率和繁殖力。其中包括一种基于备受争议的代谢生态学理论(MTE)的方法。我们还将详细阐述一个简单的模型，用于特定年龄和大小的能量分配到维持、生长和繁殖。这些模型将使我们能够测试目前关于蜥脚类动物生命周期的一些假说，这些假说涉及到它们的生殖生物学、死亡时间表和体重增长。现存分类群(鸟类、鳄鱼、海龟和哺乳动物)的死亡率和繁殖率将被用来验证我们的模型，并以我们对蜥脚类动物的外推结果为基础。关于现存分类群的经验数据将从文献中汇编，但蜥脚类动物的生长曲线将由骨组织学的原始研究产生。我们的项目提供了对MTE的进一步测试，因为对现有分类群的死亡率和繁殖力的估计将比对MTE的分析更大。

Age- and size specific mortality rates and fecundities show considerable variation among species. They reflect characteristics of life-cycles (e.g. age at sexual maturity, longevity), determine the demography (e.g. intrinsic rate of increase, generation time), and vital statistics of populations. Fecundity and growth in body size are linked because the energy uptake of an organism is limited. Body size is also linked to mortality and to the proportion of energy uptake required for the maintenance of the organism. Here, we will establish age- and size specific mortality rates and fecundities for sauropods by applying different modelling methods. These include an approach that is based on the hotly debated metabolic theory of ecology (MTE). We will also elaborate a simple model for age- and size specific allocation of energy to maintenance, growth and reproduction. These models will allow us to test a number of current hypotheses on life-cycles of sauropods with respect to their reproductive biology, mortality schedule and growth in body mass. Mortality and fecundity rates of extant taxa (birds, crocodiles, turtles and mammals) will be used to validate our models and to base our extrapolation of results for sauropods. Empirical data on extant taxa will compiled from the literature, but growth curves for sauropod will be generated by original research on bone histology. Our project provides a further test of MTE because mortalities and fecundity will be estimated for a larger group of extant taxa than those analyzed for MTE.