Demographic processes are the fundamental mechanisms through which human populations change in size, composition, and distribution. In the study of biological diversity in human populations, fertility, mortality, and migration are significant because they influence genetic variation, population structure, adaptation, and evolutionary patterns. These processes interact with environmental, cultural, social, and biological factors to shape human diversity. Fertility refers to the actual reproductive performance of individuals or populations, usually measured by the number of live births. It is one of the primary determinants of population growth. Fertility is influenced by biological factors such as age at puberty, reproductive health, nutrition, hormonal balance, and genetic traits. Social and cultural factors including marriage patterns, educational attainment, religious beliefs, family planning practices, economic conditions, and government policies also affect fertility rates. Populations with high fertility generally experience rapid growth and a younger age structure, whereas populations