A DEMOGRAPHIC APPROACH TO SELECTION

The concepts or demography provide a means of combining the ecological approach to population growth with the genetical approach to natural selection. We have utilized the demographic theory of natural selectio n developed by Norton and Charlesworth to analyze life history schedul es of births and deaths for populations of genotypes in Drosophila pse udoobscura. Our populations illustrate a stable genetic equilibrium, a n unstable genetic equilibrium and a ease of no equilibrium, We have e stimated population growth rates and Darwinian fitnesses of the genoty pes and have explored the role of population growth in determining nat ural selection, The age-specific races of births and deaths provide in sights into components nf selection, Both viability and fertility are important components in our populations.