Human Population Growth Through Time Current world population: 7.35 Billion (Nov. 2016) http://www.worldometers.info/world-population/ 2012 7 billion 13 years 1999 12 years 13 years 1974 14 years 33 years 1927 123 years 1804 Tens of thousands of years Birth and Death Rates Birth rate is reported as the number of births per __________ people Death rate is reported as the number of deaths per _________ people Calculating Population Change Immigration Emigration Population Change = { Births + _____________} – {Deaths + _______________} zero population growth (ZPG) occurs when factors that increase and decrease population size are in balance. Population Change Birth rates are higher in ______________ nations (highest on the _________ continent) Annual rate of population increase is expressed as a percentage. Country A has a birth rate of 12 per 1000 in 2000, and a death rate of 9 per 1000 in the same year. What is its rate of growth in the year 2000 (assuming no net immigration or emigration), as a percent? Since the birth and death rates are given per 1000, need to convert the difference to a percent. ____________________ Doubling time of a population can be calculated by the rule of 70: Doubling time = 70/percentage growth rate If a population of howler monkeys increases by 3.5% per year, how long will it take the population to double? ____________ Fertility Rates Replacement Fertility: Number of children a couple must have to replace themselves. ____ in developed nations ____ in developing nations (due to higher infant mortality) Total Fertility Rate (TFR): Average number of children a woman will have in her child-bearing years. Global average: ____ Developed nations: _____ Developing nations: _____ National Geographic: Population density map http://www.nationalgeographic.com/earthpulse/population.html http://metrocosm.com/history-of-cities/ https://ourworldindata.org/fertility/#total-fertility-rate-from-1950-to-2015 Population Momentum Although the average fertility rate has gone down dramatically in the past few decades (from 5 in 1950 to 2.5 in 2015), because of the large number of people (esp. below the age of 15) the population is still greatly increasing, due to the ____________ between birth and age of ______________ Singapore: Global Population Growth Through Time • World human population is now starting to show ____________ growth instead of exponential growth • Highest rates of growth—increases above _____per year— were seen briefly during the __________ • Growth rate peaked at _______in 1963, and declined to 1.1% by 2009. • Annual births have reduced to 140 million since their peak at 173 million in the late 1990s • Deaths number 57 million per year and are expected to increase to ____ million per year by ___________. • Current projections show a continued increase of ___________ (but a steady decline in the population ___________) with the population to reach between 7.8 and 10.8 billion by the year 2050. Factors That Can Decrease Fertility Rates • greater availability of reliable _______________ • greater availability of legal ______________ • change in religious beliefs, traditions, & cultural norms away from encouraging _______________. • increased ________________; • higher average ________________; • increased _________ of raising & educating children; • _____________ infant mortality (larger families if infant death common) • increase in average level of education & __________; • increased educational & employment opportunities for _______________; • greater availability of private & public ___________; • decrease in importance of _______________; Two Primary indicators of overall health of a country 1. _________________ (higher in developing nations) 2. ______________ ________________ (lower in developing nations) Birth & Death Rates Over Time • Death rates have decreased substantially during the past 100 years, due to: Improved _______________ (Green Revolution) and __________________ • birth rates have also decreased, but not as fast as death rates • the increasing difference between birth & death rates is what has led to _____________________ population growth In ____________ countries decreases in death rates are being accompanied by decreases in birth rates over time. In ______________ countries decreases in death rates have not been accompanied by as large of decreases in birth rates over time, leading to major population increases. Demographic Transition Model 1) Preindustrial Stage: ● both birth & death rates are relatively __________, ● the population does not ______________, & the population size is small. 2) Transitional Stage: ● _________ rate drops due to industrialization, increased food production, & improved health care; ● birth rates remain relatively ___________, ● the population ______________. • Many _____________ nations are in this stage. Demographic Transition 3) Industrial Stage: ● _______ rate drops & eventually approaches a balance with death rate, ● leading to a ___________ population growth. 4) Postindustrial Stage: ● birth rate & death rates approximately balance, ___________ population growth is attained, & the population stabilizes at a size much _____________ than the preindustrial size; ● if birth rate declines below death rate ______________ population growth may even be attained. http://www.cbsnews.com/news/italys-birth-dearth/ Population Age Structure Age structure refers to the proportion of the population in each age class: Examples: Examples: Examples: Spain Italy Examples: Male Female Guatemala Finland USA Russia Saudi Arabia Australia Pre-reproductive Reproductive Post-reproductive Rapidly growing Slower growing Age 0-14 Age 14-45 Age > 45 populations: populations: Zero population Negative growth: pyramid–shaped more even age growth: ___________ age structures, distribution. nearly _______ proportion of with large proportions of pre- reproductive than numbers of ____ reproductive & pre-reproductive _____________ reproductive individuals. individuals. individuals; 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. Populations of developed countries are expected to have an increasingly even age distribution through the year 2025. India vs. Japan • India: developing nation, so a wide base = fast-growing population • Japan: developed nation, narrow base = negative population growth Japan World Population Pyramid: Past, Present and Future Projections http://www.worldlifeexpectanc y.com/world-population- pyramid Case Studies: United States Census Stats: 2010: 310 mill (+8.4%) 2000: 286 mill (+13%) 1990: 253 mill (+9.8%) 1980: 231 mill (+11.43% 1970: 203 mill (+13.37%) 1960: 179 mill U.S. Immigration History Immigration in the U. S.: • as fertility ____________, immigration has become a major source of population _____________ in the U.S.; • The arrival of new immigrants and the births of their children and grandchildren account for _____ of the U.S. population increase from 1965 to the 2015 (Pew Research Center) • increasing levels of legal & illegal immigration have been happening since the 1960’s • working immigrants boost the national ______________ in the long run; but states often bear most of the cost Total Fertility in the United States Total fertility (TFR) Baby in the United States Boom had a major increase during the "baby boom" (1946– 64) & is now hovering near _______________. TFR of major racial groups in the US, 1980-2010 Baby Boom Generation Population age structure of the United States continues to show a bulge as the baby boom generation ages. As the generation leaves the workforce, there will be less competition for ______, but there will be an increased demand for _______________ for the elderly (i.e. Social Security and Medicaid). Demographic Change in the United States • By 2050, the US will see a more ___________ youth population, and the disappearance of the Baby Boom generation, which was largely __________ US Dept of Human and Health Services Case Studies: India • Early efforts at lowering population growth were unsuccessful because of poor planning, inefficiency, low status of women, extreme poverty, and lack of funds • Large regional differences exist in population and TFR. • Issues include gender imbalance, high poverty, pollution issues…see text and movie questions. • India’s total fertility rate fell to 2.3 in 2013, a significant slowdown in population growth, compared to 3.6 in 1991. • Large _______________ divide: women in villages have a fertility rate of 2.5, while that of urban residents is 1.8. • Large population _______________ • Projected to surpass China before ______. Case Studies: China • The One Child Only policy was implemented in 1979 to control growth. At the time, the population was 970 million. Part of the reason for this was a massive __________ that started in the late 1950’s. • Incentives or rewards for families who adhered to the policy included better employment opportunities, higher wages and government assistance. Those who don’t were subjected to ______, and less access to government assistance, and ______. • There have been some exceptions to the policy since the 1980’s. • China’s current population is almost _____ billion (2015) • The one child policy is believed to have prevented up to ___________births. • By 2030, China population is expected to reach its maximum, around _______billion Case Studies: China • By 2050, China is projected to have _____________ population growth