AP BIOLOGY

Detailed explanation-1: -When demographers attempt to forecast changes in the size of a population, they typically focus on four main factors: fertility rates, mortality rates (life expectancy), the initial age profile of the population (whether it is relatively old or relatively young to begin with) and migration.

Detailed explanation-2: -Many factors such as birth rate, death rate and dispersion affect population density. Death and emigration i.e. individuals moving out of a population tend to decrease population density, while births and immigration i.e. when individuals move into a population tend to increase population density.

Detailed explanation-3: -Physical factors that affect population density include water supply, climate, relief (shape of the land), vegetation, soils and availability of natural resources and energy. Human factors that affect population density include social, political and economic factors.

Detailed explanation-4: -The number of individuals living within that specific location determines the population density, or the number of individuals divided by the size of the area. Population density can be used to describe the location, growth, and migration of many organisms.