Mortality changes in a Polish rural community (1350--1972) and estimation of their evolutionary significance.

Changes in the mortality profiles of the population of 13 villages in central Poland have been studied for the medieval and nineteenth-century periods. Three measures, derived from the demographic data, were analyzed within an evolutionary context: (1) Im, the opportunity for selection through differential mortality, (2) Rpot, the potential gross reproductive rate, and (3) Ibs, the index of biological state. Changes in these indicators over time denote sharp differences in the opportunity for natural selection through differential mortality. The greatest changes are associated with technological and organizational transformations of the social system, especially during the first half of the nineteenth century.