Cycling in the slow lane: Applications of evolutionary demography to biological anthropology.

摘要

This thesis is made up of four distinct projects.;Chapter 1 first estimates confidence in the geometric rate of increase (λ) for orangutans. Under no set of demographic parameters does λ exceed 1.04, and often λ < 1 indicating population decline. This low value suggests that even modest hunting will have devastating impacts on orangutan persistence. Next, I explore the minimum values of adult and juvenile survival and fertility required for population persistence. Adult survivorship sets an absolute boundary on persistence. Values below 95% annually are incompatible with persistence. Fertility too, has a strong effect on growth rate. Decreasing the interbirth interval by one year could potential increase λ by 1% annually.;Chapter 2 uses simulation methods to incorporate temporal variability in habitat quality, hunting, and habitat loss into a model orangutan life cycle. The long-slow life history of orangutans makes their population dynamics quite robust to environmental variability. Hunting has devastating impacts on persistence. Habitat loss increases the rate of decline as well. Furthermore, the likely density-dependent effects subsequent to habitat reductions increases the average age of the population, thereby increasing the likelihood of extinction.;Chapter 3 presents an analysis of a sample of 23 mammalian life cycles. Using multivariate analyses, I found that most of the variation in the sample can be accounted for by annual fertility and age at first reproduction. In contrast, the variation in fitness elasticities is described primarily by early and late adult survival. Analysis of the convexity of the selection gradient suggests mechanisms by which the derived primate pattern of late and infrequent reproduction could evolve.;Chapter 4 is an analysis of the human life cycle based on a sample of 24 populations of varying economic, geographic, historical and ecological backgrounds. Multivariate analyses suggest that the major axes of demographic variation lie in age-specific survivorship, particularly early survival. Variation in eigenvalue elasticities is primarily accounted for by mid-life and late-life cycle loops. Analysis of the convexity of the selection gradient suggests a hypothesis for the origin of reduced-fertility reproductive strategies.