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Human population and its impact.

Population Change

An increase or decrease in the size of a population. It is equal to (Births + Immigration) - (Deaths + Emigration).

Birth rate

the number of live births per 1,000 people in a population in a given year

Death rate

the number of deaths per 1,000 people in a population in a given year

Fertility

The number of births that occur to an individual woman or in a population.

Replacement-level fertility

the number of children a couple must have to replace themselves (2.1 in developed countries, 2.5 in developing countries)

Total fertility rate (TFR)

The average number of children born to a woman during her reproductive years.

Life expectancy

The average number of years an individual can be expected to live, given current social, economic, and medical conditions. Life expectancy at birth is the average number of years a newborn infant can expect to live.

Infant mortality rate

the number of babies per 1,000 babies that die before their first birthday

Migration

the movement of people into (immigration) and out of (emigration) a specific geographic area

Factors Affecting Human Population Size

birth rates, death rates, emigration and immigration

Age Structure

the distribution of males and females among different ages in a population

Demographic Transition

The process of change in a society's population from a condition of high crude birth and death rates and low rate of natural increase to a condition of low crude birth and death rates, low rate of natural increase, and a higher total population. There are four stages: preindustrial, transitional, industrial, and postindustrial.

Preindustrial Stage

(demographic transition) birth and death rates high, population grows slowly, infant mortality high

Transitional Stage

(demographic transition) death rate lower, industrialization occurs, food production rises, better health care, population grows fast

Industrial Stage

(demographic transition) decline in birth rate, population growth slows as industrialization, medical advances, and modernization become widespread

Postindustrial Stage

(demographic transition) low birth and death rates, reaching zero population growth

Family Planning

Provides educational and clinical services that help couples choose how many children to have and when to have them.

Zero Population Growth (ZPG)

when births plus immigration equal deaths plus emigration

Reasons for Projected Growth

1. Large number of baby-boom women still in child-bearing years. 2. Increase in number of unmarried mothers (incl. teenagers). 3. Continued higher fertility rates for women in some racial and ethnic groups than for Caucasian women. 4. High levels of legal and illegal immigrants (43% of US pop. growth). 5. Inadequate family-planning services.

Doubling Time

the time required for a population to double in size; equal to 70/% growth rate

China Population Control Policy

Introduced one-child policy in 1978, in which, with various exceptions, having more than one child is discouraged. It is a restrictive policy that aimed at immediately reducing China's birth rate to replacement level and below.

India Population Control Policy

For over five decades, has tried to control population with modest success. Government provides info and advantages of small families. Contraception is encouraged to control child birth. Most population policies have been voluntary.

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