Key Issue 3. Why is Population Increasing at Different Rates in Different Countries? ◦ The...

Chapter 2: PopulationKey Issue 3

Why is Population Increasing at Different Rates in Different Countries?◦ The demographic transition◦ Population Pyramids◦ Countries in different stages of demographic

transition◦ Demographic transition and world population

growth

Key Issue 3

Countries experience changes in natural increase, fertility and mortality rate at different times & at different rates◦ Differences in local culture and economic

conditions

Demographic Transition

Several stages: beginning, middle & end◦ Stage 1: Low Growth◦ Stage 2: High Growth◦ Stage 3: Moderate Growth◦ Stage 4: Low Growth

Demographic Transition

Describe each of the 4 stages

Early civilization High levels of birth & death rates NIR of zero People depended on hunting & gathering for

food Access to food varied by year, increasing or

decreasing population

Stage 1: Low Growth

Agricultural Revolution People domesticated plants & animals Created a stable source of food

◦ Population began to increase◦ Unfavorable harvests could still result in low food

production War and disease also affected population

growth

Stage 1: Low Growth

No country remains in stage 1 today

Stage 1: Low Growth

Due to Agricultural Revolution, population grew

Around 1750, pop. Inc 10x faster CDR decreased, CBR remains about the

same Margin causes increase in population (NIR)

Stage 2: High Growth

Industrial Revolution Began in England, 1750

◦ Spread to Europe & North America Industrial technology (steam engine, mass

production, powered transportation) Led to wealth:

◦ Improved sanitation◦ Food & water supplies

Stage 2: High Growth

Africa, Asia, Latin America◦ Did not reach stage 2 until 1950s+

Medical Revolution◦ Eliminated traditional causes of death◦ Longer & healthier lives◦ Ex: vaccines, penicillin & insecticides

Stage 2: High Growth

Reached when CBR drops sharply Began in Europe & North America in 1900s Social customs cause CBR to drop

◦ People CHOOSE to have less children◦ Improved probability of infant survival

Economic changes:◦ Large families no longer needed for farms

Families moved to city jobs◦ Children become more expensive in urban areas

Stage 3: Moderate Growth

Where are the sudden spikes of population?

CBR is equal to CDR, NIR approaches ZERO Zero Population Growth (ZPG) A TFR approx 2.1 produces ZPG Immigration can affect ZPG, where TFR

needs to be even lower

Stage 4: Low Growth

TFR of 2.1 or below is needed to reach ZPG. Observations?

Social Customs changing population◦ Women entered work force◦ Shift away from farm jobs◦ Daycare for young children◦ Birth control◦ More wealth Inc. in leisure time, not suitable for

children

Stage 4: Low Growth

Russia (Eastern Europe)◦ Negative NIR, deaths exceed births

Cause: Communist Rule◦ Indadequate pollution control◦ Pessimism about having children

Stage 4: Low Growth

Countries that pass through all four stages have completed a cycle

Stage 1: ZPG to Stage 4: ZPG Stage 1: high CBR & CDR Stage 4: low CBR & CDR

Demographic Transition

Good Case Study:◦ accurate records of population (past 1000yrs)◦ No boundary changes◦ Not greatly affected by migration

The Demographic Transition in England

Explain the Demographic Transition◦ Define each stage◦ Explain what leads to each transition to next

stage◦ Provide examples

Writing Assignment

Stage of Demographic Transition determines what population of a country looks like

Percentage of each age group Gender distribution

Population Pyramids

A bar graph that displays a country’s population by age and gender

◦ Percentage of total populationin 5yr age groups, youngest at bottom, oldest at top

◦ Percentage of males, females represented by length of bars

Population Pyramids

CBR determines shape of pyramid Stage 2 country: high growth

◦ High CBR, large number of children◦ Broad base of pyramid (wide at bottom)

Stage 4 country: low growth◦ Large number of older people◦ Broad top of pyramid

Population Pyramids

Dependency ratio: number of people who are too young or too old to work, compared to people in productive years

Dependents are: 0-14 and 65+yrs old Determine dependency ratio of classroom

Age Distribution

Stage 2◦ 50% of population are dependents (1:2)◦ Young dependents outnumber elder dependents

10:1 Stage 4

◦ 33% of population are dependents (1:1)◦ Amt of young dependents = Elder dependents

How will amount and age of dependents impact a society?

Age Distribution

Sub-Sahara Africa & Stage 2 (high-growth) countries◦ Large percentage of pop. under age 15◦ Strains country’s resources

Hospitals, schools, daycare◦ Job scarcity post high school

Age Distribution

Percentage of elders increases as countries move towards Stage 4 of Dem. Trans.◦ Declining CBRs◦ Improved medical care ◦ Higher incomes

Europe: 65+ is 16% of population Sub-Saharan Africa: 65+ is 3% of population

Age Distribution

United States, Canada, Japan, Europe◦ More than ¼ of gov’t expenditures go to health care, Social

Security & programs for older populations

Stage 3 & 4 countries◦ Higher population of elderly◦ Causes higher CDR

What concerns are there with our aging population?

Age Distribution

Number of males per hundred females in a population

Slightly more males born than female Males have higher death rates Europe & North America 95: 100 (m:f) Rest of world is 102:100 (m:f)

What could be the reason?

Sex Ratio

Read newspaper article and answer questions

Life Expectancy Shrinks for Poor People in the US

United States◦ Under age 15yrs old, 105:100 (m:f)◦ Women outnumber men around age 40◦ Why????◦ 58% of population 65+ are women

Sex Ratio

LDCs High mortality rate during childbirth Larger percentage of young people (males

outnumber females) Lower percentage of older people (females

are more numerous)

Sex Ratio

What could explain these differences in age and gender throughout the United States?

Population Pyramids

What do you know about birth rates for African-Americans and Hispanics?

Similar Population PyramidsWhy???

What do we know about these locations? How does that help explain the age distribution?

Stage 1: low growth: none Stage 2: high growth: Cape Verde Stage 3: moderate growth: Chile Stage 4: low growth: Denmark

Countries in Different Stages of Demographic Transition

12 small islands off the coast of W Africa Famine kept it in Stage 1 until 1950 Antimalarial campaign moved it to Stage 2

Cape Verde: Stage 2

Shifted from rural to urban Moved from Stage 1 to 2 with medical

advancements (smallpox, malaria) Moved to Stage 3 because of gov’t family

planning initiatives, 1966◦ (prevented abortions for unwanted births)

Reversed family planning policies, 1970

Chileans continue to have large families Large Catholic population

Chile: Stage 3

Similar to England’s trends in population Since 1970s, CBR = CDR…ZPG Population is only increasing from

immigration

Denmark: Stage 4