Chapter 2 AP Human Geography

Overpopulation

When a population is too large for the available resources to adequately support it.

• Can result in shortages of food, water, housing, and medical care.

• Depends on available resources and technology, not just the number of people.

Ecumene

The portion of Earth's surface that is permanently inhabited by people.

• Includes cities, farms, and settled rural areas.

• Excludes or has very little permanent settlement in places such as Antarctica and extremely harsh environments.

Arithmetic density

The average number of people per unit of total land area.

Physiological density

The number of people per unit of arable (farmable) land.

Agricultural density

The number of farmers per unit of arable land.

CBR — Crude Birth Rate

The number of live births per 1,000 people in a population per year.

CDR — Crude Death Rate

The number of deaths per 1,000 people in a population per year.

TFR — Total Fertility Rate

The average number of children a woman is expected to have during her lifetime, based on current age-specific fertility rates.

• Higher TFR generally means faster potential population growth.

• Replacement-level fertility is about 2.1 children per woman in many developed countries.

NIR — Natural Increase Rate

The rate at which a population grows from births minus deaths, excluding migration.

Doubling Time

The estimated number of years it takes a population to double if its growth rate remains constant.

World Life Expectancy

The average number of years a newborn is expected to live under current mortality conditions

developing countries population trends

Higher birth rates in many countries, Often higher TFR, Population tends to grow faster, Younger population, Often higher infant mortality

developed countries population trends

Lower birth rates, Often lower TFR, Population growth tends to be slow or negative, Older population, Often lower infant mortality, Life expectancy tends to be higher

IMR — Infant Mortality Rate

The number of deaths of infants under age one per 1,000 live births in a given year.

Expansive

expansive pyramid

stationary Pyramid

Constructive pyramid

Stage 1 — Low growth (DTM)

• High birth rate.

• High death rate.

• Little natural increase because births and deaths are both high.

Stage 2 — Rapid growth (DTM)

• Birth rate remains high.

• Death rate drops rapidly.

• Population grows quickly.

Improvements in sanitation, food supply, and healthcare reduce deaths before birth rates decline.

Stage 3 — Slowing growth (DTM)

• Birth rate declines.

• Death rate stays relatively low.

• Population continues growing, but more slowly.

Education, urbanization, contraception, and changing family preferences contribute to smaller families.

Stage 4 — Low growth (DTM)

• Low birth rate.

• Low death rate.

• Population growth is slow or stable.

Associated with highly developed economies and smaller families.

Thomas Malthus

argued that population could grow faster than the food supply.

• Population grows exponentially in his model.

• Food production grows arithmetically, or in a linear pattern.

• Eventually, population could exceed the food supply, causing shortages and hardship.

Stage 1 — Pestilence and famine (ETM)

• Infectious diseases, malnutrition, and famine are major causes of death.

• Life expectancy is low and unpredictable.

Stage 2 — Receding pandemics (ETM)

• Epidemics become less frequent or deadly.

• Improved sanitation, nutrition, clean water, and medical care reduce deaths.

• Life expectancy rises.

Stage 3 — Degenerative and human-created diseases (RTM)

• Chronic diseases become more prominent causes of death.

• Examples include heart disease, cancer, and diabetes.

• Longer life expectancy means more people live to ages when chronic illnesses are common.

Stage 4 — Delayed degenerative diseases (ETM)

• Medical advances help people live longer with chronic diseases.

• Death from some chronic diseases is delayed.

• Life expectancy tends to be high.

Carrying capacity

Carrying capacity is the number of people an environment can sustainably support with its available resources and technology.