key issue 3. why is population increasing at different rates in different countries? ◦ the...
TRANSCRIPT
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
