AP Human Geography Test Unit 2 Pt. 2

Crude Birth Rate (CBR):

Number of live births per 1,000 people per year.

Crude Death Rate (CDR):

Number of deaths per 1,000 people per year.

Rate of Natural Increase (NIR):

Birth rate minus death rate, converted into a percentage. Does not include migration.

Doubling Time:

How long it takes for a population to double. Divide 70 by the NIR percentage.

Total Fertility Rate (TFR):

Average number of children a woman is expected to have in her lifetime.

TFR of 2.1:

Replacement-level fertility; the average number of children needed to replace the parents and keep the population stable over time, without migration.

Zero Population Growth (ZPG):

When a population stays about the same size because births and deaths are balanced, accounting for migration.

Life Expectancy:

Average number of years a person is expected to live.

Population Pyramid:

A graph showing a population's age groups and the number of males and females.

Sex Ratio:

Comparison of the number of males to females in a population.

Dependency Ratio (0–14 and 65+):

Compares the number of children and elderly people to the working-age population (usually ages 15–64).

Youth Dependency Ratio (0–14):

Compares the number of children to the working-age population.

Elderly Dependency Ratio (65+):

Compares the number of people age 65 and older to the working-age population.

Pyramid Shapes and Growth Patterns:

The shape of a population pyramid helps predict whether a population will grow, stay stable, or decline.

Pyramid Shape for Rapidly Growing Population:

Triangle; a wide base shows many young people and high birth rates.

Pyramid Shape for Steady Population:

Rectangle; age groups are more evenly distributed, suggesting slow or stable growth.

Pyramid Shape for Declining Population:

Upside-down triangle; a narrow base shows low birth rates and fewer young people.