On the Mathematics of Populations

Selection acting on unobserved heterogeneity is a fundamental issue in the mathematics of populations. As recognised in disciplines as diverse as demography [11, 23, 24], ecology [10, 9], evolution [21] and epidemiology [1, 4, 5], in any population, individuals differ in many characteristics and it is essential that researchers understand which of these are under selection and how selection processes operate. Here I describe conceptual and methodological developments in demography and ecology, and discuss the importance of adopting similar approaches in evolution and epidemiology.