Mortality in AP Human Geography

Deaths as the subtraction side of natural increase

Every population change comes down to three numbers: births, deaths, and migration. Mortality is the deaths side. It sits in Unit 2: Population and Migration, under Topic 2.4: Population Dynamics, which asks you to explain why populations rise and fall, both today and in the past.

The main tool is the rate of natural increase (RNI), which is births minus deaths, ignoring migration. Say a country has a crude birth rate of 30 per 1,000 and a crude death rate of 10 per 1,000. That's a gap of 20 per 1,000, so divide by 10 to get an RNI of 2.0%.

From there you can estimate doubling time with the rule of 70: 70 ÷ 2 = 35 years. The exam doesn't allow a calculator, so expect numbers that divide cleanly. If mortality rises to 20 per 1,000 while births stay at 30, RNI drops to 1.0% and doubling time stretches to 70 years.

Why falling death rates set off population booms

In the historical pattern, population surges usually start when death rates drop while birth rates stay high. That's Stage 2 of the demographic transition model. In industrializing Europe, better food supplies, cleaner water, and sanitation cut deaths well before families started having fewer children.

The gap between births and deaths explains the boom. A common wrong answer says growth came from people having more babies. Usually the birth rate didn't change much. People just stopped dying as young, especially infants and children.

The Epidemiological Transition Model tracks the same shift from the mortality side. It describes how the main causes of death move from infectious disease and famine toward chronic illnesses like heart disease and cancer as a society develops.

Social, cultural, political, and economic causes of death rates

The course says mortality is shaped by human factors as well as biology. Sorting your examples into these four categories makes an explanation easier to score:

• Economic: wealth pays for clinics, clean water systems, and enough food. Poverty limits all three.
• Political: war, genocide, and government collapse raise deaths. Public health programs like vaccination campaigns lower them.
• Social: education levels, especially women's education, affect child health and how families use medical care. This links to Topic 2.8, which says changing roles for women have shaped mortality patterns along with fertility and migration.
• Cultural: beliefs and practices around diet, medicine, and care for the sick or elderly can push death rates up or down.

The strongest answers name a specific mechanism. "Healthcare" by itself is vague. "Expanded childhood vaccination lowered deaths from infectious disease" shows how the factor actually changes the rate.

The crude death rate trap with aging countries

Mortality is the concept. The crude death rate (CDR) is one statistic that measures it, counting total deaths per 1,000 people per year. The CDR doesn't adjust for age, and that sets up a classic trap.

A wealthy country with a very old population, like Japan, can have a higher CDR than a poorer country with a very young population, such as many in Sub-Saharan Africa. Older people die at higher rates even with excellent healthcare. So a high CDR doesn't automatically signal a less developed country.

To judge health conditions, look at infant mortality rate and life expectancy. Topic 7.3 lists infant mortality rate as a development indicator, and life expectancy is one of the components of the Human Development Index. If a question asks which data best shows access to healthcare, infant mortality usually beats CDR.

Reading mortality data in stimulus questions

A table listing birth rate, death rate, infant mortality, and life expectancy for a set of countries is one way mortality shows up in multiple choice. It can also appear on a map or in a question with no stimulus at all. Other questions ask about scale. For example, infant mortality mapped by county for every county in Ohio means the extent of the study is one state, analyzed through county units.

On the free-response section, mortality can show up in Question 1 (no stimulus), Question 2 (One-stimulus question), or Question 3 (Two-stimuli question). A free-response question can draw on more than one unit, so mortality from Unit 2 might be paired with development from Unit 7, such as linking infant mortality to GNI per capita or healthcare access.

Match the task verb. If a part asks you to define mortality, give a clear definition. If it asks you to explain, name a cause or consequence and show how it works, using one of the four factor types above. When there's a stimulus, quote actual numbers from it, and say what a difference in death rates does to natural increase.