Human Population: Growth & Distribution Chapter 11 Human Population: Growth & Distribution © Brooks/Cole Publishing Company / ITP

Outline 1. Factors Affecting Human Population Size birth & death rates 2. Population Age Structure age structure diagrams, developing vs. developed countries 3. Solutions: Stabilizing Human Population computer models, demographic transition 4. Case Studies United States, India, China 5. Human Population & Sustainability © Brooks/Cole Publishing Company / ITP

Human Population Growth How would you describe the population before 1700?

Human Population Growth How would you describe the population after 1700?

Human Population Growth What kinds of historical events were taking place in the 1700s and 1800s?

Human Population Growth How has the amount of time it takes for the population to grow by 1 billion changed?

Human Population Growth Year Reached Years to Reach 1 billion 1850 Tens of thousands 2 billion 1930 80 3 billion 1960 30 4 billion 1974 14 5 billion 1987 13 6 billion 1999 12

Factors Affecting Human Population Size Human population is currently growing exponentially: What will be the ultimate size of the human population? What is Earth's carrying capacity? (How many humans can Earth support?) © Brooks/Cole Publishing Company / ITP

Factors Affecting Human Population Size Population change is calculated as the difference between individuals entering and leaving a population: Population Change Births + Immigration Deaths + Emigration – = Birth rate – is the number of births per thousand people Death rate – is the number of deaths per thousand people Zero population growth (ZPG) occurs when factors that increase and decrease population size balance © Brooks/Cole Publishing Company / ITP

Crude Birth & Death Rates Developed countries tend to have lower birth rates & death rates than developing countries. Why? © Brooks/Cole Publishing Company / ITP

Population Change The annual rate of population increase is generally expressed as a percentage. What information can you gather from this map? © Brooks/Cole Publishing Company / ITP

Population Size by Country The world's ten most populous countries in 1998, with projections of population size in 2025. © Brooks/Cole Publishing Company / ITP

Population Size by Continent Population size by region in 1998, with projections of population size in 2025. There are about 84 million births each year. (97% of new births are in developing countries) © Brooks/Cole Publishing Company / ITP

Birth & Death Rates Over Time In developed countries, decreases in death rates are being accompanied by decreases in birth rates over time. © Brooks/Cole Publishing Company / ITP

Birth & Death Rates Over Time In developing countries, decreases in death rates have not been accompanied by as large of decreases in birth rates over time, leading to major population increase. © Brooks/Cole Publishing Company / ITP

Average TFR (births per woman) Population Size Fertility Rates Measure of the number of children that will be born Replacement Fertility - Number of children needed to replace the parents (2.1 in developed countries, 2.5 in some developing countries) 2) Total Fertility Rate (TFR) - Average number of children each woman has in a population Average TFR (births per woman) 2.8 - Developing Countries 2.4 - Middle Income Countries 1.7 - Upper Income Countries © Brooks/Cole Publishing Company / ITP

Total Fertility in the United States Total fertility in the United States had a major increase during the "baby boom" (1946–1964) & is now hovering just below replacement level. © Brooks/Cole Publishing Company / ITP

Factors Affecting Fertility Rates What factors decrease human fertility levels? What causes people to have fewer children? How do you get a baby astronaut to fall asleep? You rocket. © Brooks/Cole Publishing Company / ITP

Factors Affecting Fertility Rates The following are significant factors that decrease human fertility levels: increase in average level of education & affluence decrease in importance of child labor increased urbanization increased cost of raising & educating children increased educational & employment opportunities for women decreased infant mortality higher average age of marriage greater availability of private & public pensions greater availability of reliable birth control greater availability of legal abortions change in religious beliefs, traditions, & cultural norms away from encouraging large families © Brooks/Cole Publishing Company / ITP

TFR (births per woman)

Teen Pregnancy Which industrialized country has the highest teenage pregnancy rate? How many teenage girls become pregnant each year? What percentage of those pregnancies were unplanned? The United States 872,000 78%

Birth Control Typical effectiveness of birth control methods in the United States: © Brooks/Cole Publishing Company / ITP

Birth Control Typical effectiveness of birth control methods in the United States (continued): © Brooks/Cole Publishing Company / ITP

Death Rates “It’s not as if people suddenly started breeding like rabbits; it’s just that they stopped dying like flies.” Peter Adamson Life expectancy - The number of years a newborn can expect to live. Developing Countries - 64.6 years Middle Income Countries - 69.6 years Upper income Countries - 78.2 years © Brooks/Cole Publishing Company / ITP

Death Rates “It’s not as if people suddenly started breeding like rabbits; it’s just that they stopped dying like flies.” Peter Adamson Infant mortality - Number of babies out of every 1,000 that die within a year of birth Angola – 182.3 India – 32.3 United States – 6.3 Singapore – 2.3 World Average – 42.1 © Brooks/Cole Publishing Company / ITP

Infant Mortality Rate vs. GDP

Death Rates Infant death rates are lower in developed countries than developing countries © Brooks/Cole Publishing Company / ITP

Birth & Death Rates Over Time The rapid growth in the world's population has not resulted from an increase in birth rates, but rather a major decrease in death rates. death rates have decreased markedly during the past 100 years birth rates have also decreased, but not as fast as death rates the increasing difference between birth & death rates is what has lead to exponential population growth the patterns of change in birth & death rates over time are different for developed vs. developing countries © Brooks/Cole Publishing Company / ITP

Think About It Which age group do you think has the biggest population in Chester County?

Chester County, PA

Population Age Structure Age structure refers to the proportion of the population in each age class: prereproductive (0–14 years) reproductive (15–44 years) postreproductive (45 & up) © Brooks/Cole Publishing Company / ITP

Population Age Structure Age structure of a rapidly growing vs. a slower growing population. Rapidly growing populations have pyramid–shaped age structures, with large numbers of prereproductive individuals. Slower growing populations have a more even age distribution. © Brooks/Cole Publishing Company / ITP

Population Age Structure Age structure of populations with zero growth vs. negative growth. Populations with zero population growth have nearly equal proportions of prereproductive & reproductive individuals; whereas populations with negative growth have a greater proportion of reproductive than prereproductive individuals. © Brooks/Cole Publishing Company / ITP

Population Age Structure Population age structure of the United States continues to show a bulge as the “baby boom” generation ages. This has been compared to watching a boa constrictor swallow a pig. © Brooks/Cole Publishing Company / ITP

Matching Review B C A D Rapid Growth Zero Growth Negative Growth Slow Growth

Demographic Indicators Fig.11–15 © Brooks/Cole Publishing Company / ITP

Population Age Structure Developing countries are expected to continue to have a pyramid shape through the year 2025, although the age structure will become somewhat more evenly distributed. Fig.11–14a © Brooks/Cole Publishing Company / ITP

Population Age Structure Populations of developed countries are expected to have an increasingly even age distribution through the year 2025. Fig.11–14b © Brooks/Cole Publishing Company / ITP

Developed vs. Developing

Demographic Transition A generalized model of demographic transition (four stages): © Brooks/Cole Publishing Company / ITP

Demographic Transition Preindustrial Stage: Birth rate and death rates are high & approximately equal population does not increase population size is small Death rate Birth rate Total pop. © Brooks/Cole Publishing Company / ITP

Demographic Transition 2) Transitional Stage: death rate decreases because of industrialization, increased food production, & improved health care birth rate remain high population grows rapidly © Brooks/Cole Publishing Company / ITP

Demographic Transition 3) Industrial Stage: birth rate drops & eventually approaches a balance with death rate slowing of population growth Total pop. Birth rate Death rate © Brooks/Cole Publishing Company / ITP

Demographic Transition 4) Postindustrial Stage: birth rate & death rates approximately balance zero population growth population stabilizes at a size much higher than the preindustrial size if birth rate declines below death rate negative population growth may even be attained Total pop. Death rate Birth rate © Brooks/Cole Publishing Company / ITP

Computer Models of Human Population This computer model projects what might happen if the world's population & economy continue to grow exponentially at 1990 levels. © Brooks/Cole Publishing Company / ITP

Computer Models of Human Population This computer model projects how we can avoid overshoot & collapse to make a fairly smooth transition to a sustainable future by stabilizing fertility at two children per couple. © Brooks/Cole Publishing Company / ITP

Case Studies – Population Control in India In 1952, India began the first national family planning program The program has been disappointing because of poor planning, low status of women, extreme poverty, & lack of funds Couples still have an average of 3.5 children because of the belief that they need children to work & care for them in old age India © Brooks/Cole Publishing Company / ITP

Case Studies – Population Control in China Since 1970, China has initiated efforts to better feed its people & control population growth Strict population control measures prevent couples from having more than one child Although considered coercive, the policy is significantly slowing population growth China © Brooks/Cole Publishing Company / ITP

Case Studies – Immigration in the U.S. As fertility decreases, immigration has become a major source of population increase in the U.S. In 1998, the U.S. received about 935,000 legal immigrants & 400,00 illegal immigrants Increasing levels of legal & illegal immigrants are expected © Brooks/Cole Publishing Company / ITP

Immigration in the U.S.A.! © Brooks/Cole Publishing Company / ITP

Immigration in the United States Should the U.S. reduce the number of immigrants allowed into the country? Is the U.S. (or other wealthy countries) obligated to accept immigrants from very poor countries?

Human Population & Sustainability How can governments reduce population growth? improve access to family planning & reproductive health care improve heath care for infants, children, & pregnant women encourage development of national population policies improve equality between men & women increase access to education, especially for girls increase the involvement of men in child rearing & family planning reduce poverty reduce & eliminate unsustainable patterns of production & consumption © Brooks/Cole Publishing Company / ITP