AP BIOLOGY

Detailed explanation-1: -The two main factors affecting population growth are the birth rate (b) and death rate (d). Population growth may also be affected by people coming into the population from somewhere else (immigration, i) or leaving the population for another area (emigration, e).

Detailed explanation-2: -“Summing” It All Up. Overall, population grows or shrinks through two very basic components – natural change (births minus deaths) and migration (domestic plus international).

Detailed explanation-3: -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-4: -Emigration is the movement of individuals out of a population. This decreases the population size and growth rate.