AP HUGS Unit 2: Demographic Transiton Model & Epidemiological Transition Model

Demographic Transition Model: Stage 1

Stage 1: Low Growth

Birth Rate: Very high and fluctuating

Death Rate: Very high and fluctuating

Natural Increase Rate (NIR): Very low or zero

Societal Characteristics: Pre-industrial societies; no sanitation, poor healthcare, subsistence farming, famine and disease common

Economy Type: Traditional/subsistence economy (primary sector)

Modern Examples: None today (historic stage — hunter-gatherer or early agricultural societies)

Demographic Transition Model: Stage 2

Stage 2: Increasing Growth

Birth Rate: Still very high

Death Rate: Rapidly declining due to better sanitation, medicine, and food supply

Natural Increase Rate (NIR): Very high (population boom)

Societal Characteristics: Industrial Revolution or Medical Revolution begins; urbanization increases; population starts to grow rapidly

Economy Type: Early industrial economy (primary → secondary transition)

Modern Examples: Sub-Saharan Africa, Afghanistan, Yemen

Demographic Transition Model: Stage 3

Stage 3: Moderate Growth

Birth Rate: Rapidly declining due to urbanization, education, and access to contraception

Death Rate: Slowly declining, stabilizes at low level

Natural Increase Rate (NIR): Moderate growth

Societal Characteristics: More women in education/workforce; smaller families; shift to industrial jobs; improved healthcare

Economy Type: Industrial economy (secondary sector dominance)

Modern Examples: Mexico, India, Indonesia, South Africa

Demographic Transition Model: Stage 4

Stage 4: Decreasing Growth

Birth Rate: Low

Death Rate: Low and stable

Natural Increase Rate (NIR): Low or zero (equilibrium)

Societal Characteristics: Highly urbanized, advanced healthcare, high life expectancy, widespread gender equality, delayed marriage and childbirth

Economy Type: Post-industrial economy (tertiary/service sector)

Modern Examples: United States, Canada, Australia, South Korea

Demographic Transition Model: Stage 5

Stage 5: Declining Population

Birth Rate: Very low, often below replacement level

Death Rate: Low but may exceed birth rate

Natural Increase Rate (NIR): Negative (population decline)

Societal Characteristics: Aging population, labor shortages, high dependency ratio, pronatalist policies introduced to boost birth rates

Economy Type: Post-industrial/knowledge-based economy (quaternary/quinary sectors)

Modern Examples: Japan, Germany, Italy, South Korea

Epidemiological Transition Model: Stage 1

Stage 1: Pestilence and Famine

Main Cause of Death: Infectious diseases, famine, and poor sanitation (e.g., Black Plague)

Reason for Declining Birth Rate: Birth rate stays high (no decline yet) because high infant mortality encourages large families

Reason for Declining Death Rate: Death rate fluctuates but remains high due to lack of medicine and food insecurity

Role in NIR: Very low or zero growth; high birth and death rates cancel each other out

Societal Characteristics: Pre-industrial societies, little medical knowledge, poor hygiene, subsistence farming

Examples: No current countries (historical stage)

Epidemiological Transition Model: Stage 2

Stage 2: Receding Pandemics

Main Cause of Death: Epidemics decline due to better sanitation, nutrition, and medicine

Reason for Declining Birth Rate: Birth rates remain high; cultural and economic norms still encourage large families

Reason for Declining Death Rate: Rapid decline because of improved public health, cleaner water, and basic medical advances

Role in NIR: NIR rises sharply as death rates fall but birth rates stay high (population boom)

Societal Characteristics: Industrial or medical revolution; urbanization begins

Examples: Egypt, Nigeria, Afghanistan

Epidemiological Transition Model: Stage 3

Stage 3: Degenerative and Chronic Diseases

Main Cause of Death: Chronic and degenerative diseases like heart disease, cancer, and diabetes replace infectious diseases

Reason for Declining Birth Rate: Declines due to urbanization, education, and access to contraception

Reason for Declining Death Rate: Continues to fall slowly due to medical improvements and better living conditions

Role in NIR: NIR slows down; population grows at a moderate rate

Societal Characteristics: Industrial societies, better healthcare, and rising life expectancy

Examples: Mexico, Turkey, Brazil

Epidemiological Transition Model: Stage 4

Stage 4: Delayed Degenerative Diseases

Main Cause of Death: Chronic diseases remain but are delayed by medical advances and healthier lifestyles

Reason for Declining Birth Rate: Birth rate very low due to changing social roles, economic development, and family planning

Reason for Declining Death Rate: Death rate very low; advanced medicine prolongs life

Role in NIR: NIR is very low or stable (zero population growth)

Societal Characteristics: Post-industrial societies, high life expectancy, aging population

Examples: United States, United Kingdom, South Korea

Epidemiological Transition Model: Stage 5

Stage 5: Reemerging Infections and Parasitic Diseases

Main Cause of Death: Reemergence of infectious diseases due to antibiotic resistance, globalization, and poverty

Reason for Declining Birth Rate: Birth rate very low due to lifestyle choices, high cost of living, and family planning

Reason for Declining Death Rate: Death rate may rise slightly as new and resistant diseases appear

Role in NIR: NIR becomes negative (population decline)

Societal Characteristics: Aging populations, lower fertility, migration used to offset workforce decline

Examples: Japan, Germany, Italy