5Human Population Growth Historically Early Hunter GatherersNomadic, With a Strong Sense of the EarthPracticed Intentional Birth ControlRise of AgricultureNecessary for SurvivalAnimals became extinct via predation and altered habitatHumans began to cultivate own food
6C. Agriculture Gives Rise to Cities Food Produced in Country, Consumed in CityFood wastes are no longer returned to soilSoil becomes less productiveWaste of Populations Concentrated in CitiesPopulation Control in Medieval SocietiesInfanticidePlagues
7D. IndustrializationView of Children During Early Phases of Industrial GrowthValued as cheap source of income and cheap laborExponential growth of populationsBy 1900s, Birth Rate in Industrialized World DroppedRise in standards of livingSafe and inexpensive means of birth control introducedIncrease in the cost of child rearing
9Current World Population Population Clock Vital Events (per time unit)Global population was 6,669,203,826On February 27, 2007 at 6:13 amThe global population grows by:Nearly 2.3 persons per secondsNearly 8,343 persons per hourOver 200,234 persons per dayOver 73 million persons per year
18Population Pyramids Graphic device: bar graph shows the age and gender composition of a regionhorizontal axis: gendermale: left-hand female: right-handabsolute number of people or %vertical axis: age5-year or 10-year age groups
19Factors affecting pop pyramids Medicine Disease Technology War Baby Boomers Natural DisastersWomen deciding to delay familyMore attention to health (graying of America)Gay population increasing!! (~1-5%)Immigration / emigration
20Population Pyramid with young cohorts Male cohortsFemale cohorts
21Population Pyramids High Growth: Afghanistan Population Pyramids on the WebHigh Growth: AfghanistanModerate Growth: MexicoZero Growth: France, RussiaNegative Growth: Austria or Italy
22Bottom Graph: Projected population pyramid for 2025 when one can again see the large cohorts that were born between 1985 and This large number of births is just the “echo effect” of the baby boom bet mid 1960’s and mid-1970’s. Each couple should only have one child according to government policy—so why is the base so large?
23Top Graph: China’s baby boom that peaked in late 1960’s and early 1970’s. Started in 1950’s-now visible as those generations in 2000 were years of age.Middle Graph: Birth cohorts rapidly declined. Children born bet in 2007 belonged to the smallest birth cohorts after the baby boom. These ind were born bet 1978 & 1985 when family planning took place.
31Human Population Dynamics There are just three sources of change in population size —Fertility (Birth rates)Mortality (Death rates)"natural decrease" refers to population decline resulting from more deaths than birthsNet migration- is the number of immigrants minus emigrants
34Rates of Global Pop. Change use: International Data Base http://www Rates of Global Pop. Change use: International Data Base then Online Demographic AggregationCBR (crude birth rate) = # births / 1000 population1990: 24 now: 20.6CDR (crude death rate) = # deaths / 1000 population1990: 9 now: 8.8
35Human Population Dynamics Total fertility rate (TFR)The average number of children born to a womanAverage in developed countries = 1.5Average in developing countries = 3.8Worldwide 1990: 3.1 now: 2.76On each of the country lines, there is a graph representing that country’s fertility rate. As I scroll down the country list, look at the trends of each of the countries and their fertility rates. Identify the trends.
38Total Fertility Replacement Rate = The number of children a couple must have to replace themselves (i.e. 2 children)- Also known as replacement-level fertilityA TFR of 2.1 for developed countries withlow infant and child mortality ratesAfrica RFR = 2.5 children per coupleMali RFR = 2.7 (ties in with the growth rate—see later)Source:
42What Is Family Planning? DefinitionMeasures enabling parents to control number of children (if they so desire)Goals of Family PlanningNot to limit birthsFor couples to have healthy childrenFor couples to be able to care for their childrenFor couples to have the number of children that they want
44What Methods are Used to Control Births? Preconception Birth Control MethodsBarrier MethodsCondomVaginal spongeDiaphragmSpermicidesHormonal ContraceptivesPillInjections and implantsSterilizationPostconception Birth Control MeasuresIntrauterine DeviceRU-486 PillAbortion
45Contraceptive Use Worldwide People in industrialized countries enjoy easy access to contraceptives while those in LDCs do not.In the U.S., teens and poor women are least likely to use contraceptives.Severe problems are associated with teen pregnancy.
47Maternal Deaths per 100,000 Live Births Source: WHO, UNICEF, UNFPA Maternal Mortality in 1995: Estimates Developed by WHO, UNICEF AND UNFPA, 2001.
48Growth RateThe average annual rate of change for a population within a specified time period.Noted in a percentage.Growth Rate = (b + i) – (d + e)Total Population(births + immigration) – (deaths + emigration)1990: 1.5% now: 1.19%growth rates have come down
49Overall, the world population is growing at a rate of about 1 Overall, the world population is growing at a rate of about 1.7 per cent; if this rate continues, the population will double in 42 years.Unabated, such a rate would lead to a point about 2000 years hence when the mass of humanity would weigh more, and be larger, than the Earth.But, the growth rate is decreasing
50Rule of 70Rule of 70 – standard to determine how long it takes for a population to double.Focus on: migration, aging, youth bulge, urbanization and new socio-economic-political consequences.Some countries will double—some will not.World is in j-curve growth.
52Rule of 70 Assume that the pop doubles every 70 years. Problem: If the population has a growth rate of 2%, how long will it take for the population to double?Answer: 70/2 =35 years to double.
53Demographic Transition Movement of a nation from high population growth to low population as it develops economicallyTransition as a result of four stagesStage 1—Birth and death rates are both highStage 2—Death rates fall; birth rates remain high; growth rate risesStage 3—Birth rates fall as standard of living rises; growth rate fallsStage 4—Growth rate continues to fall to zero or to a negative rate
55Five Stages of the Demographic Transition Used to be 4, now 5 stagesbirth rates, death rates and growth rates systematically change through time as societies change:modernize, urbanizegain access to technology
56Population Pyramids and Demographic Stages characteristics shapes of ‘pyramids’wide base (true pyramid)wide middle (bulge), somewhat wider baseurn- or bottle-shapedreversed pyramiddifferent shapes--different dynamics
57Stage 1: Pre-Industrial high birth rates, high (at time erratic) death rates, low growth ratesstage for much of human history, traditional societiespractically no country today
59Stage 2 TRANSITIONAL high birth rates, declining death rates, rising growth ratesimprovements insanitation (water)and medicinein Europe during Industrial Revolutionin developing countries since the 50s/60smuch of Africa today, some countries of Asia (Afghanistan, Nepal, etc.)
60Population Pyramid and Demographic Transition Stage 2: wide basestage 3: wide middlestage 4: slenderstage 5: narrow base
61Stage 3 INDUSTRIALIZED continued decline of death rates, declining birth rates,growth rates decline fromhigh to lower levelschange in behavior: adaptation to lower death rate, in particular infant mortality rateeconomic change: urbanization (incentive to have fewer children)Mexico today
62Population Pyramid and Demographic Transition Stage 2: wide basestage 3: wide middlestage 4: slenderstage 5: narrow base
63Stage 4 & 5 POST-INDUSTRIALIZED Stage 4: low birth rates, low death rates, lowgrowth ratesUnited States todayStage 5: low birth rates, rising death rates, declining growth rates (if birth rates drop below death rates: negative growth rates)several countries of Europe today (Austria)
64Population Pyramid and Demographic Transition Stage 2: wide basestage 3: wide middlestage 4: slenderstage 5: narrow base
65Population Pyramid and Demographic Transition Stage 2: wide basestage 3: wide middlestage 4: slenderstage 5: narrow base
72The Graying of JapanFamily-planning access, cramped housing, expensive land, late marriage, education cost --> voluntary decrease in birth rateLow immigration rateHealth insurance and pension - 45% of national income; could -->low economyIllegal immigration bolsters work force
74Influencing Population Size Most countries restrict immigrationCanada, Australia, U.S. - most immigrationInvoluntary immigration results fromarmed conflictenvironmental degradationnatural disaster --> environmental refugees~1% of developing nations pop. EmigratesMigration from rural to urban areas
75Family Planning: reduce births and abortions 59% contraceptive use in developed countries -46% overall, up from 10% in 60sFP reduces children's social services needsFP reduces risk of childbearing deathsFP effectiveness depends on program design and funding:good in some counties with good programpoor in other counties
76Family Planning: reduce births and abortions -2 Services not always accessible; add female teenagers and sexually active unmarriedAdd birth control for men (sperm-killing device used in China)If developed countries provided $17 billion/ year, and each person pays $4.80/year, average family size would be 2.1 and world population would be 2.9 billion