Changes in Population

"The size of any population doesn't stay the same for long"

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Births and Deaths

Populations change all the time, This is is due to birth rate. The word birth rate means the number of births in a population in a certain amount of time. Suppose a wolf pack of 50 produces 100 cubs in a year, the birth rate is 100 cubs a year. Eventually the circle of life happens, and the wolves will die, this is death rate. The main way wolves leave a population.

Population Statement

A population statement can be written as a mathematical statement using the less than or greater than sign.

If birth rate > death rate, population size increases


If death rate > birth rate, population size decreases

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Immigration and Emigration

Another way populations can change is when individuals move into a population, this is called immigration. Populations decrease in size when individuals leave a population, this is called emigration. Immigration means moving into a population, emigration means moving out a the population