By: MIR AZAD KALAM, SAPTAMITA PAL
Darwinian principles of natural selection highlight fertility and mortality differentials as key drivers of evolutionary change. Quantifying these pressures with demographic selection indices provides insight into how health disparities shape evolutionary dynamics in human populations. This study examines rural–urban differences in the intensity of natural selection in Howrah district, West Bengal, using Crow’s Index and the Johnston and Kensinger Index. A cross-sectional ethnographic field study was conducted among 665 ever-married women, randomly sampled from both rural and urban areas. For analysis, reproductive and mortality data from women aged 45 years and older were evaluated (rural: 113; urban: 169). The results show that rural populations experience stronger evolutionary pressures, primarily due to higher mortality rates and greater fertility variance. These differences reflect the impact of socioeconomic inequality, unequal access to healthcare, and environmental conditions on demographic and evolutionary processes. The study highlights the usefulness of demographic selection indices in assessing health inequalities and evolutionary dynamics in contemporary populations.
