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| Description: Total fertility rate (TFR) = average number of children born per female member of a population during her lifetime Replacement fertility = the TFR that keeps the size of a population stable For human replacement fertility is equal to a TFR of 2.1 Increasing urbanization decreases TFR Children now go to school, and increase costs With social security, elderly parents need fewer children to support them Greater education allows women to enter the labor force, with less emphasis on child rearing Whether a population grows, shrinks, or remains stable depends on: Rates of birth, death, and migration Birth and immigration add individuals Death and emigration remove individuals Crude birth rate (nativity or natality) = number of births per 1000 individuals Crude death rate (mortality) = number of deaths per 1000 individuals Technological advances led to dramatic decline in human death rates widening the gap between crude birth rates and crude death rates and resulting in population expansion Growth rates in many countries have been declining, even without population control policies Decline due in part from a steep drop in birth rates Picture Stats: Views: 342 Filesize: 89.41kB Height: 801 Width: 875 Source: https://biology-forums.com/index.php?action=gallery;sa=view;id=35710 |