World Geography / Unit 3: Human Geography
3.2 Population Growth and Change
Notes
Population changes through births, deaths and migration.
- Birth rate and death rate are births or deaths per 1,000 people per year. Natural increase = birth rate minus death rate. Example: 30 births and 10 deaths per 1,000 gives 20 per 1,000, or 2.0 percent growth.
- Fertility rate is the average number of children per woman. About 2.1 is the replacement level needed to keep a population stable in a country with low child mortality.
- The demographic transition model has stages: (1) high birth and death rates, (2) falling death rates and rapid growth, (3) falling birth rates and slower growth, (4) low birth and death rates and stable population. Some countries now have birth rates below replacement and an aging population.
- A population pyramid with a wide base shows many children and fast growth; a narrow base shows low birth rates.
Practice
A country has 25 births and 7 deaths per 1,000 people per year, with no migration. What is its natural increase?
$25 - 7 = 18$ per 1,000, which is 1.8 percent.
In which stage of the demographic transition model does the population grow fastest?
Falling death rates with high birth rates produce rapid growth.
A population pyramid has a very narrow base and a wide top. What does this suggest?
Few children and many older adults describe an aging population.
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