Chapter 7

1. Chapter 7 The Human Population

2. Malthus

3. Green Revolution • In the 1960s, the efforts of agriculture scientists began to be realized in increased crop production in many areas of the world, especially Asia. Selective plant breeding produced high yielding varieties of rice and other crops, particularly maize, sorghum, and wheat. These high yield varieties (HYVs) perfromed best under high applications of fertilizer, and also required more expenditures for pesticides, irrigation, farm machinery, etc. Rice is a particular success story, and as the leading cereal crop, helps to pull the world yield rates upwards. Soybean production also has climbed dramatically overall, and stayed somewhat ahead of population growth. • The overall consequence is that per capita food production has contradicted the doom-sayers of the 1960s: during the greatest episode of population growth in human history, food supply per capita grew. Note that Asia did better than the world average, while Africa did worse. The Green Revolution's great success with rice explains the former; lack of success with breeding new arid-land crop varieties, combined with a large dose of political instability, explain Africa's worsening condition. Per capita grain production in Africa is down 12% since 1981 and down 22% since 1967. Some 20 years ago, Africa produced food equal to what it consumed; today it produces only 80% of what it consumes.

4. Demography – study of human populations and trends Growth Rate = CBR – CDR 10 (for a region add immigr. CBR; add emmigr. to CDR) Rule of 70 (Doubling Time) = 70 growth rate

5. Changes in Population Size Fertility Life Expectancy Infant and child mortality Aging and disease Definition – aver. number of yrs that an infant born in a particular country can be expected to live. (High life expectancy is a good predictor of high resource consumption, high enviro impact, but w/ better health care • TFR – total fertility rate • Replacement-level fertility

6. Age Structure Diagram Wide at the bottom – more younger people More like a column, less like a pyramid – slow or no growth With greater number of older people (bulge in middle or inverted pyramid) – population is shrinking. Population size is on horiz. axis. Age is on vert. axis.

7. Demographic Transition As a country moves from a subsistence economy to an industrialization and increased influence, it undergoes a predictable shift in pop growth. Phase 1 – slow or no growth Phase 2 – rapid growth ex. China or India Phase 3 - pop stabilization ex. USA, Canada Phase 4 – pop decline ex. ome Western Euro countries

8. Phase 1Slow Population Growth • CBR = CDR • Life expectancy short • Infant mortality high because of disease, lack of health care poor sanitation; many children do not live to adulthood • Farming a way of life; children do chores and are expected to care for elderly parents • War, HIV pushing some countries back (CDR increased)

9. Phase 2Rapid Population Growth • Birth rate remains the same, as CDR declines • Improved sanitation, food water, health care, vaccinations • Couples continue to have large families because it takes at least one generation for families to notice decline in infant mortality.

10. Phase 3Stabile Population Growth • Economy and education system improve. • Family size decreases, while income increases • Society shifts from subsistence farming to economic specialization; more time for more members to attend higher education. Women can join the workforce. • CBR and CDR decrease.

11. Phase 4Declining Population Growth • High levels of economic development and affluence • Ex. UK, Germany, Japan and Russia all have CBR well below CDR • Social and economic effects substantial; fewer young people in labor force, and more older people retired strain pension systems and social security, need for health care workers rises.