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Chapter 3. Key Issue 3 Why is population increasing at different rates in different countries?. Demographic Transition Model. All countries have experienced some changes in natural increase, fertility, and morality rates at different times and at different rates.
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Chapter 3 Key Issue 3 Why is population increasing at different rates in different countries?
Demographic Transition Model • All countries have experienced some changes in natural increase, fertility, and morality rates at different times and at different rates. • Although rates vary among countries, a similar process of change is operating • Because of local cultural and economic conditions, the demographic transition diffuses to individual countries at different rates
Demographic Transition Model • Stage 1: Low Growth • HIGH BIRTH and DEATH rates • Most of Humanity’s occupancy on earth • People depended on Hunting/Gathering • Food supplies were unpredictable • War • Disease- no modern medicine • Pre- Industrial Revolution • NO COUNTRY STILL IN STAGE ONE!!!!
Stage 2: High Growth • Death rate drops, Birth Rate stays high • Occurred in most countries during 18th and 19th centuries, during the Industrial Revolution. • Improved sanitation/hygiene • Improved medical practices • More food available/ new technology • CBR high, NIR high = rapid growth • MDC’s went through stage 2 by 1800’s • LDC’s didn’t start in stage 2 until 1950’s • Thanks to medical revolution • Several periphery nations still in Stage 2
Stage 3: Moderate Growth • Birth rate begins to drop, death rate low • Pop still grows because CBR still higher than CDR • NIR slows • MDC’s moved into stage 3 in early 1900’s • Most Asian and Latin American countries today • Sudden drop of birth rates due to changes in social customs • Economic changes • Urban societies
Stage 4: Low Growth • Reaches stage when zero population growth is achieved. • BR=DR • NIR = 0 • Called zero population growth (ZPG) • below replacement level • Mainly Europe and United States • Changes in lifestyle encourage small families • Countries that have NEGATIVE growth: • Russia and other Eastern European Countries • Cause: Communist Rule
5th stage? • Not identified yet • Characterized by higher CDR than CBR • Irreversible population decline • Japan? • Italy? • Russia?
ENGLAND EXAMPLE • Stage 1 • Pre-1750 • Norman invasion 1066 • Population = 1 million • Black death • Famines/ bad harvests • Stage 2 • 1750: CBR and CDR -40 • By 1800: CBR 34, CDR 20 • Industrial Revolution • NIR 1.4% , pop increased from 6- 30 mill • Stage 3 • After 1880 • CBR declined sharply • Between 1880- 1970 pop only increased .7 % per year • Stage 4 • Since 1970s • CBR/ CDR even • TFR below replacement levels
EXAMPLES Cape Verde: Chile: Stage 3 Denmark stage 2 stage 4
WHY ISN”T EVERY COUNTRY AT STAGE 4???? • Demographic change • Sudden decline in CDR • Core nations: • Industrialization led to wealth • Wealth led to scientific innovations • Semi/ Periphery nations: • Diffusion of scientific and technological innovations • All have accepted technology (vaccines, medications, etc.) • BUT….not all countries have “changed” social customs
Demographic Transition and World Population Growth • Huge population explosion during 2nd ½ of 20th century • No country in stage 1, few in stage 4 • Causes • Drop in DR b/c of technology • Drop in BR b/c of change in social custom
Population Pyramids • A population pyramid is a bar graph that displays age and gender of a population • Males on left, females on right • 5 year age groups • Shape determined by CBR • Demographic transition gives a country a distinctive population structure • Influenced by: • % of Population in each age group • Distribution of Male and Females
Age Distribution • Most important factor is dependency ratio: • # of people too old or young to work compared to the # of people in their productive years • Three age groups: • - 0 – 14 • - 15 – 64 • - 65 + • ½ of all people in stage 2 countries (LDCs/ Periphery) are dependent • Mainly young • 1/3 of all people in MDC’s (Core) are dependent • Mainly old
Problems • The large amount of Children in Africa strain resources • “graying” populations of U.S. and Europe are burdens on the government
Sex Ratio • # of males per hundred Females • Stage 2 countries have low % of women due to childbirth deaths
Population Pyramids • Allows demographers to identify changes • Population cohorts • Group of individuals who share a common temporal demographic experience • Example: • Deficit of births after a war