APHG Unit 3 - Population

agricultural density

the number of farmers per unit of arable land. Example: a country with 1 million farmers and 500,000 hectares of arable land has an agricultural density of 2 farmers per hectare.

arithmetic density

the total number of people per unit of land area (total population ÷ total land area). Example: Bangladesh has a very high arithmetic density.

antinatalist policy

a government policy that discourages or limits births to slow population growth. Example: China’s one child policy.

arable land

land suitable for growing crops.

carrying capacity

the maximum population an area can support sustainably given its resources and environment.

census

an official, usually periodic count of a country’s population that also collects demographic information. Example: the U.S. conducts a census every 10 years.

climate

the long term average weather patterns of a region. It is a physical factor that influences where people live. Example: people avoid extreme deserts and polar regions.

contraception

methods used to prevent pregnancy. Wider access is a major reason fertility rates fall.

Cornucopians

people who believe technology and innovation will solve resource shortages and that population growth is manageable or beneficial.

crude birth rate (CBR)

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

crude death rate (CDR)

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

demographic

relating to the characteristics of a population, such as age, sex, birth rates, and death rates.

demographic transition

the process by which a country shifts from high birth and death rates to low birth and death rates as it develops.

demographic transition model

a model with 4 or 5 stages that shows how a country’s CBR, CDR, and population growth change over time as it industrializes.

demography

the scientific study of human populations, including their size, structure, and change.

dependency ratio

the number of dependents (people under 15 and over 64) compared to the working age population (ages 15 to 64). Example: a high ratio means fewer workers supporting more dependents.

distribution

the arrangement of something across space. In population geography, it is where people live across Earth’s surface.

doubling time

the number of years it takes a population to double at its current growth rate (70 ÷ NIR). Example: at an NIR of 2%, doubling time is 35 years.

ecological footprint

the amount of land and resources a person or population needs to sustain its consumption and absorb its waste.

economic

relating to the production, trade, and use of money and resources. Economic factors such as jobs and trade influence where people settle.

ecumene

the portion of Earth’s surface that is permanently inhabited by humans.

epidemic/epidemiology

an epidemic is the rapid spread of a disease within a region. Epidemiology is the study of the causes, spread, and control of diseases.

Epidemiologic Transition Model (ETM)

a model describing how the main causes of death in a country change over time as it develops. Example: from infectious disease to chronic, degenerative diseases.

eugenics

the discredited belief in improving a population by controlling reproduction, often by encouraging or preventing certain groups from having children.

fertility

the ability to produce children. In geography it usually refers to the rate of births in a population.

gendercide

the systematic killing of members of a specific sex. Example: sex selective abortion of female fetuses in China and India.

infant mortality rate (IMR)

the number of deaths of infants under 1 year old per 1,000 live births.

landforms

physical features of Earth’s surface, such as mountains, plains, and plateaus. Example: people tend to cluster in flat, fertile river valleys.

life expectancy

the average number of years a person is expected to live, based on current death rates.

Malthus

Thomas Malthus, the English economist who argued population grows faster than food supply.

Malthusian theory

the idea that population grows geometrically while food supply grows arithmetically, so famine, disease, and war will eventually check population growth.

maternal mortality rate

the number of women who die from pregnancy or childbirth complications per 100,000 live births.

mean center of population

the average location of a population’s distribution. Example: the U.S. mean center has shifted west and south over time.

medical revolution

the improvements in medicine, sanitation, and public health (especially after 1750 and spreading widely after World War II) that sharply lowered death rates.

Megacity

a city with more than 10 million people.

Metacity

a city with more than 20 million people.

mortality

death. It is often measured as a death rate, such as the CDR or IMR.

national increase rate (NIR)

the percentage a population grows in one year, calculated as CBR minus CDR (divided by 10), not counting migration. Example: CBR 30 and CDR 10 gives an NIR of 2%.

Neomalthusians

modern followers of Malthus who argue that growing populations strain resources and environments, and who support population control.

overpopulation

when a population exceeds the carrying capacity of its environment, so resources cannot support everyone.

pandemic

a disease outbreak that spreads across multiple countries or continents, affecting a large part of the world. Example: COVID 19.

physiological density

the number of people per unit of arable land. It shows the pressure a population puts on farmland.

politics

the activities and decisions of governments and how power is used. Political factors such as war, laws, and policies influence where people live and population change.

population pyramid

a bar graph showing a population’s age and sex structure. Example: a wide base means high birth rates.

pronatalist policy

a government policy that encourages higher birth rates. Example: Russia and Denmark offer financial incentives for having children.

sex ratio

the number of males per 100 females in a population.

Super aged countries

countries where a very large share of the population (about 20% or more) is age 65 and older. Example: Japan.

total fertility rate (TFR)

the average number of children a woman is expected to have in her lifetime. The replacement level is about 2.1.

zero population growth (ZPG)

a state where a population is neither growing nor shrinking, usually when TFR is about 2.1 and the NIR is about 0.