APHUG module 9/10

1. Population dynamics: the big picture

• Population dynamics = how human populations grow and change. Population is fluid, meaning it can increase, decrease, or stay stable.

• Births and immigration add people; deaths and emigration remove people.

• Ending population = starting population + births − deaths + immigrants − emigrants.

• Population grew rapidly after the Industrial Revolution because deaths—especially infant/child deaths—fell while births remained high.

• Better food, sanitation, clean water, and medicine lowered deaths.

• Population measures help reveal a place’s living standards, development, age structure, and future needs.

2. Know these measures and formulas

• Live birth = a baby born alive.

• For CBR/CDR, count births/deaths for the whole year, but use the midyear population.

• “Crude” means the measure uses everyone without adjusting for age/sex differences.

• These measures can apply to countries or smaller areas.

3. Birth-rate categories

• Low: 10–20 per 1,000. Common in developed, industrialized, urbanized areas; North America, Europe, and much of Asia and Latin America. Your class notes also list Oceania.

• Transitional: 20–30 per 1,000. Examples: Algeria, Egypt; Belize, Guatemala, Honduras, Haiti, Bolivia; Jordan, Syria, Israel; most Central Asian countries, Pakistan, Mongolia.

• High: above 30 per 1,000 in the textbook. Common in sub-Saharan Africa. Your class sheet phrases it as 30+.

• CBR varies with age-sex composition, economic development, and expectations about family size.

• More women of childbearing age generally → higher CBR.

4. TFR and replacement fertility

• TFR measures children per woman; CBR measures annual births per 1,000 people.

• TFR is better for comparing reproduction because it focuses on women, indicates average family size, and helps predict population changes.

• Replacement fertility = 2.1: enough children to replace both parents over time.

• It is slightly above two because some children do not survive to adulthood.

• Sustained below-replacement fertility → eventual natural decrease; replacement fertility → eventual stability. Changes are not immediate, and migration also matters.

• Examples: Niger 7.2, compared with Europe 1.6; Bulgaria 1.6, with a textbook projection of 28% population loss by 2050.

5. Five factors affecting fertility

• Economic development: Better contraception access and lower child mortality generally → fewer children. Agricultural families may want children for farm labor.

• Religion/culture: Traditions may encourage large families or discourage birth control. But Italy and Spain had TFRs of 1.3 despite Catholic traditions.

• Education: More education and paid work for women generally → smaller families. Your class notes especially emphasize this.

• Gender roles: Expectations that men/women should have many children can raise fertility.

• Government policies: Birth restrictions lower fertility; financial incentives and maternity leave can encourage births. China’s restrictions since the 1970s are the textbook example.

6. Death rates: watch the age structure

• A high CDR does not automatically mean poor health care. Older populations naturally have more deaths.

• Developed countries may have higher CDRs but better health care than younger, less-developed countries.

• Bulgaria and Latvia: High CDRs associated with aging.

• Sub-Saharan Africa: Higher deaths associated with poverty, disease, and war.

• U.S., Canada, Australia: Young immigrants help keep CDR lower.

• Bahrain, Kuwait, Oman, Qatar, UAE: Textbook CDRs of only 1–2 per 1,000.

• Death rates have generally declined as living conditions and medical technology improve. Your class notes give global life expectancy as approximately 73–74 years.

7. Infant mortality: living standards

• IMR = deaths under age one; child mortality = deaths under age five.

• IMR is considered the best single indicator of living standards because it reflects health, nutrition, sanitation, education, housing, and medical access.

• More-developed countries → lower IMR; less-developed countries → higher IMR.

• Clean water, sanitation, and health care—especially prenatal care—help reduce deaths.

• Textbook examples: about 5 per 1,000 in more-developed countries; commonly 50–70 in sub-Saharan African countries.

• Source difference: Your class notes give average world IMR as 28; the textbook gives 31. Keep the source straight.

8. RNI and zero population growth

• Births > deaths → positive RNI → natural increase.

• Deaths > births → negative RNI → natural decrease.

• Births = deaths → RNI 0% → zero population growth (ZPG).

• RNI excludes ALL migration. Immigration can offset natural decrease.

• Birth rates vary more between countries than death rates, so high birth rates usually explain high RNI.

• China: (12 − 7) ÷ 10 = 0.5%.

• Nigeria: (39 − 12) ÷ 10 = 2.7%.

• ZPG does not mean no births/deaths or an unchanged age structure. Aging can cause labor shortages and slower economic growth.

9. Doubling time and the rule of 70

• Doubling time = result; rule of 70 = calculation method.

• 70 ÷ growth percentage = approximate years to double.

• U.S.: 70 ÷ 0.3 ≈ 233 years.

• Nigeria: 70 ÷ 2.6 ≈ 27 years.

• Use 0.3 for 0.3%, not 0.003.

• Faster growth → shorter doubling time.

• The textbook calculation uses RNI, so it excludes migration and assumes the rate stays constant.

• A doubling population needs services for twice as many people: water, housing, jobs, education, health care.

• The book uses 2.7% for Nigeria’s RNI example but 2.6% for its doubling example.

10. Demographic Transition Model (DTM)

• Shows how birth rates, death rates, and natural growth change as countries industrialize and urbanize.

• Deaths fall first → growth speeds up. Births fall later → growth slows.

• Stage 3 still grows: births remain above deaths, but the gap gets smaller.

• Stages 1 and 4 both have little growth, but Stage 1 has high rates and Stage 4 has low rates.

• Examples: many sub-Saharan countries—Stage 2; developing countries—Stage 3; developed countries—Stage 4; Japan/Germany—likely Stage 5.

• Sweden and Mexico broadly follow the pattern at different times; their real graphs have ups and downs rather than smooth lines.

• Origins: Warren Thompson, 1929; Frank Notestein, 1945; based mainly on Northern Europe.

• Limitations: countries can stall, skip stages, or reverse. Examples: China’s one-child policy accelerated transition; Angola/Afghanistan’s conflicts raised deaths; wealthy Oman retained relatively high fertility.

11. Epidemiological transition

• Abdel Omran’s theory: Better living standards and health care change the main causes of death.

• General shift: infectious/parasitic/nutritional diseases → chronic/degenerative diseases, with more deaths occurring at older ages.

• Originally three phases; scholars added the fourth.

• Black Death: Killed about one-third of Europe in the mid-1300s—an epidemic example.

• Many sub-Saharan countries—Phase 2; textbook examples for Phase 3 include developed countries, South Korea, and South Africa.

• Cancer, heart disease, stroke, dementia illustrate chronic/degenerative diseases.

• COVID-19, HIV/AIDS, Ebola, and measles outbreaks show infectious threats can return; progress is not guaranteed.

• DTM asks: How do birth/death rates and growth change? Epidemiological transition asks: What are people dying from?