Population Growth Curves and Carrying Capacity

Population growth changes with births, deaths, immigration, and emigration. When birth rates and immigration are higher than death rates and emigration, a population increases. When deaths and emigration are higher, the population decreases. These changes can be shown on a graph of population size over time.

Population growth is an increase in the number of individuals in a population, and many factors can limit this growth.

For example, the size of a puffer fish population changes over time. Individuals move into an area through immigration and leave through emigration. The population also changes when new fish are born, and others die.