Population Size, Vital Rates and Demography
This historical Ecology URL remains available for compatibility. Its principal concepts are now developed across Lectures 08 and 09 of the current course.
Population size changes through births, deaths, immigration, and emigration. Demography describes the structure and vital rates of a population, including natality, mortality, age structure, sex ratio, survivorship, and movement. These variables help explain whether a population is growing, stable, declining, or being reshaped by migration and differential survival.
A useful population-change framework is to treat births and immigration as additions, and deaths and emigration as losses. Interpretation still depends on time interval, population boundary, sampling design, and whether all demographic processes are measured consistently.
Continue with Lecture 09: Natality, Mortality, Migration, Age Structure and Life Tables.