How do birth, death, fertility, and migration rates affect population size? What factors can affect these rate


birth: the more births, the faster a population grows.
death: the more deaths, the less populations grows
fertility= the higher the fertility rate, the faster a population grows.
migration rate-= the more people who move into an area, the faster a population grows.

Factors: disease, food, etc.
If the birth rate is faster than the death rate, then the population grows up to a certain point. When the environment can no longer support more individuals (strain on resources), then the population should level out.

Fertility, like he said above. If individuals are more fertile and produce more progeny per birth or reproduce quickly, then the population will increase to the stable level.

Migration can go both ways. Immigration is movement into a new area. Emigration is movement away. So, if immigration is greater than emigration, the population grows.

Population size is capped by a few factors: land, which is especially important for territorial animals like lions; number of mates available (if there's only 1 female but 20 males, then the population can grow only slowly); available food - less food, fewer individuals born; waste products - obvious in bacteria, when the waste they produce prevents more reproduction; water and other nutrient availability; natural disasters and stochastic events, like fire, earthquakes, etc; hunting by man.
note: i'm referring to humans here, of course.

birth rate: adds to the population, somehow dependent on the fertility rate. legislative actions and moral beliefs could affect this (ex. China's one-child policy, the Catholic Church's discouragement of contraceptives)

death rate: reduces the population number

fertility rate: the rate in which a certain number of women are expected to give birth successfully. health of the populace, especially women, could slightly affect it

migration rate: the rate in which people move into or go out of the country for some time, wherein the population size would generally increase or decrease, respectively. the current condition of the country largely determine the migration rates; (ex. wealth/dearth of economic opportunities, security issues)

This article contents is post by this website user, doesn't promise its accuracy.

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