Evolutionary ecology of human life history

Abstract

The human life history is characterized by several unusual features, including large babies, late puberty and menopause, and the fact that there is a strong cultural influence on reproductive decisions throughout life. In this review I examine human life history from an evolutionary ecological perspective. I first review the evidence for life history trade-offs between fertility and mortality in humans. Patterns of growth, fertility and mortality across the life span are then discussed and illustrated with data from a traditional Gambian population. After outlining the stages of the human life course, I discuss two phenomena of particular interest in evolutionary anthropology, both of which are apparently unique to humans and neither yet fully understood. First, I discuss the evolution of menopause, the curtailing of female reproduction long before death. The evidence that this evolved because investment in existing children's future reproductive success is more important than continuing child bearing into old age is reviewed, along with data relating to the biological constraints that may be operating. Second, I discuss the demographic transition. Declining fertility at a time of increasingly abundant resources represents a serious challenge to an evolutionary view of human life history and behaviour, and is thus examined in detail. Parental investment in children in competition with each other may be key to understanding both of these unusual human phenomena. Copyright 2000 The Association for the Study of Animal Behaviour.