Human PopulationHuman Population

Notes also at Notes also at http://www.manskopf.com

Big IdeaBig Idea

The size and growth rate of The size and growth rate of human population has changed human population has changed drastically over the last 200 drastically over the last 200 years. Those changes have led to years. Those changes have led to profound changes to almost profound changes to almost every place on Earth.every place on Earth.

China’s One-Child PolicyChina’s One-Child Policy• In 1970, the average Chinese woman had In 1970, the average Chinese woman had

about six children. about six children. • Since 1979, China has used a system of Since 1979, China has used a system of

rewards and punishments to enforce a rewards and punishments to enforce a one-child limit to slow population growth. one-child limit to slow population growth.

• In 2005, there were 32 million more males In 2005, there were 32 million more males than females in China under the age of 20than females in China under the age of 20

Talk About It Is it ethical for governments to limit or encourage human population growth?

Talk About It Is it ethical for governments to limit or encourage human population growth?

Studying Human PopulationsStudying Human Populations

Describe how the size and growth rate for Describe how the size and growth rate for human population has changed over human population has changed over historyhistory

What factors lead to population changesWhat factors lead to population changes Analyze populations using Age Structure Analyze populations using Age Structure

DiagramsDiagrams Terms: Demography, Age Structure, Terms: Demography, Age Structure,

Survivorship, Fertility, Migration, Life Survivorship, Fertility, Migration, Life ExpectancyExpectancy

• Describe what you see on this graph

•How long did it take to get to 1 billion, than 2, 3,4,5,6

•How many people are living today?Did You Know? Basic sanitation was rare even in the medical profession until 1861, when Dr. Ignaz Semmelweis discovered that doctors’ hand washing greatly reduced patient mortality.

Did You Know? Basic sanitation was rare even in the medical profession until 1861, when Dr. Ignaz Semmelweis discovered that doctors’ hand washing greatly reduced patient mortality.

•Why did it take so long to reach 1 billion?

•Why do you think it took off around the late 1880s?

Interesting Fact: Of all the humans ever born, approximately 6-7% are alive today.

Studying Human PopulationsStudying Human Populations

Demography: the Demography: the study of human study of human populationpopulation

How many people live How many people live where?where?

How long are you How long are you expected to live?expected to live?

How many children How many children are you likely to have.are you likely to have.

DemographyDemography• • Population size:Population size: Number of peopleNumber of people

• Population Population density:density: Number Number of people living per of people living per mimi2 2 (or per km(or per km22))

• Population Population distribution:distribution: How How people are people are distributed within distributed within an areaan area

Exponential GrowthExponential Growth

Exponential Growth: rapid growth often seen as J-Shaped curve on a graph

Can that growth continue?

Forecasting Population SizeForecasting Population Size

Will new schools be Will new schools be needed?needed?

Should we be Should we be building more building more housing?housing?

Should farming Should farming practices be practices be improved?improved?

Predictions like this Predictions like this often wrong because often wrong because human behavior human behavior changeschanges

Forecasting Population SizeForecasting Population Size

Age Structure: the Age Structure: the distribution of ages distribution of ages in a populationin a population

Age Structure Age Structure Diagrams aka Diagrams aka population pyramidspopulation pyramids

What is useful about What is useful about these diagrams?these diagrams?

•What are these age-structure diagrams showing?

•What are the “reproductive years” Why is that important in forecasting future population growth?

•Which “type” of countries are going to see most of the population growth?

•Which “type” of countries do people live longer lives?

• Survivorship: percent of population likely to survive a given age

What causes population to rise?What causes population to rise?Population

Changes =

(births + immigration) – (deaths + emigration)

For world population growth we are only concerned about births and deaths.

Fertility RatesFertility Rates

Fertility Rates: Fertility Rates: number of number of babies born babies born each year per each year per 1,000 women1,000 women

Total fertility Total fertility raterate

Replacement Replacement rate fertilityrate fertility

Fertility and WomenFertility and Women Two main factors Two main factors

impact fertility rates impact fertility rates worldwideworldwide

Education level of Education level of women (knowledge of women (knowledge of family planning)family planning)

Economic level of Economic level of womenwomen

Generally, on average, Generally, on average, more education, more more education, more wealth = lower wealth = lower fertility ratesfertility rates

• What does this graph show?

•How has U.S. fertility rates changed?

Migration: movement Migration: movement INTO (immigration) or INTO (immigration) or OUT of (emigration) OUT of (emigration) an areaan area

Population

Change = (births + immigration) – (deaths + emigration)

U.S. growth continues because of both births and immigration

Death rates on the Death rates on the decline… decline… people people living longerliving longer

Why?Why?

Population

Change = (births + immigration) – (deaths + emigration)

Better hygiene, Better hygiene, sewage disposal, sewage disposal, clean water, clean water, medicines, medicines, education, access education, access to food, nutritionto food, nutrition

Life ExpectancyLife Expectancy

Life Expectancy: Life Expectancy: average number of average number of years members of years members of a population are a population are expected to liveexpected to live

Improvement in Improvement in most of worldmost of world

Lower INFANT Lower INFANT MORTALITYMORTALITY

Compared to our neighbors

Major changes in U.S. over last 100+ years

Demographic TransitionDemographic TransitionEvery Country Goes Through ItEvery Country Goes Through It

Explain what you see on this chart

• Stage 1 : High Birth AND Death rates = little population change

• Stage 2 : Death Rates Fall, Birth Rates Still High = Population Growth

• Stage 3: Death Rates Low, Birth Rates Drop = Population Growth Slows

• Stage 4: Death Rates Low, Birth Rate Low = Population Declines

DESCRIBE EACH STAGE: WHAT DO YOU SEE?

CalculationsCalculations

A town currently has a population of A town currently has a population of 20 people. If 10 people are born, 8 20 people. If 10 people are born, 8 people die, 3 immigrate and 1 people die, 3 immigrate and 1 emigrate, what is the population? emigrate, what is the population?

CalculationsCalculations

USA currently has a population of USA currently has a population of 320,000,000 people. If 5,000,000 320,000,000 people. If 5,000,000 people are born, 2,000,000 people people are born, 2,000,000 people die, 200,000 immigrate and 50,000 die, 200,000 immigrate and 50,000 emigrate, what is the population?emigrate, what is the population?

Rule of 70: Doubling TimeRule of 70: Doubling Time

Currently, a city has a population 10 Currently, a city has a population 10 million. When will it reach 20 million if the million. When will it reach 20 million if the population is growing at 10%?population is growing at 10%?

How long will it take a population to go How long will it take a population to go from 200 to 400 if it grows at 5% a year?from 200 to 400 if it grows at 5% a year?

ReviewReview

Describe how the size and growth rate for Describe how the size and growth rate for human population has changed over human population has changed over historyhistory

What factors lead to population changesWhat factors lead to population changes Analyze populations using Age Structure Analyze populations using Age Structure

DiagramsDiagrams Terms: Demography, Age Structure, Terms: Demography, Age Structure,

Survivorship, Fertility, Migration, Life Survivorship, Fertility, Migration, Life ExpectancyExpectancy

Ages 0-14Ages 0-14 Ages 15-44Ages 15-44 Ages 45-85+Ages 45-85+

Rapid GrowthGuatemala

NigeriaSaudi Arabia

Rapid GrowthGuatemala

NigeriaSaudi Arabia

Slow GrowthUnited States

AustraliaCanada

Slow GrowthUnited States

AustraliaCanada

MaleMale FemaleFemale

Zero GrowthSpainAustriaGreece

Zero GrowthSpainAustriaGreece

Negative GrowthGermanyBulgariaSweden

Negative GrowthGermanyBulgariaSweden

Population Age StructurePopulation Age StructurePopulation Age StructurePopulation Age Structure

Fig. 10-14 p. 184Fig. 10-14 p. 184

Population TrendsPopulation Trends

What are problems associated with What are problems associated with rapid human population growth?rapid human population growth?

Compare developed and developing Compare developed and developing (lesser developed) countries.(lesser developed) countries.

Investigate strategies for reducing Investigate strategies for reducing population growth.population growth.

Terms: arable land, urbanization, Terms: arable land, urbanization, suburban sprawl, developed and suburban sprawl, developed and developing countriesdeveloping countries..

Problems With Rapid GrowthProblems With Rapid Growth

Lack of infrastructure to Lack of infrastructure to support populationsupport population

Water suppliesWater supplies SewersSewers RoadsRoads SchoolsSchools PowerplantsPowerplants HospitalsHospitals HousingHousing

Problems With Rapid GrowthProblems With Rapid Growth

Using up resources Using up resources too quicklytoo quickly

Water suppliesWater supplies Food Supplies, Food Supplies,

VegetationVegetation Wood/fuels : wood Wood/fuels : wood

supplies critical to supplies critical to life in many life in many regionsregions

Problems With Rapid GrowthProblems With Rapid Growth

Unsafe water Unsafe water suppliessupplies

Sewage mixing Sewage mixing with water supplieswith water supplies

Cholera, Cholera, Dysentery, Dysentery, TyphoidTyphoid

1 Billion lack clean 1 Billion lack clean waterwater

3 million/yr die3 million/yr die

Clean Water LackingClean Water Lacking

If the millions of women who haul water long distances had a faucet by their door, whole societies could be transformed.

Problems With Rapid GrowthProblems With Rapid Growth

Land becomes scarceLand becomes scarce Arable land : land Arable land : land

that can grow cropsthat can grow crops Tradeoffs made : Tradeoffs made :

agriculture, agriculture, housing, natural housing, natural habitats habitats

Which do you think Which do you think typically wins out?typically wins out?

Problems With Rapid GrowthProblems With Rapid Growth

Urbanization: Urbanization: movement of movement of people from rural people from rural areas to citiesareas to cities

Much of world is Much of world is going throughgoing through

Increased demand Increased demand on infrastructureon infrastructure

Problems With GrowthProblems With GrowthIn U.S.In U.S.

Suburban sprawl: Suburban sprawl: work in cities live in work in cities live in suburbssuburbs

Decay of inner Decay of inner citiescities

Increased trafficIncreased traffic Loss of farmlandLoss of farmland Decreased wildlife Decreased wildlife

habitathabitat

Suburban SprawlSuburban Sprawl

Diverse World PopulationDiverse World Population

Developed CountriesDeveloped Countries US, Canada, Japan,

Australia, New Zealand and most of Europe. High Per Capita GDP. (1.2 billion people)

Comparing a developed country

to

Moderately Developed

to

Developing (lesser developed)

Did You Know? On average, 1 American consumes as much natural resources as 5 Chinese or 13 Pakistanis.

Did You Know? On average, 1 American consumes as much natural resources as 5 Chinese or 13 Pakistanis.

Diverse World PopulationDiverse World Population

Developing (lesser Developing (lesser developed) developed)

5.2 billion people living with very little 97% of population

growth.

Percent of World’s

Developingcountries

Developedcountries

Population

Populationgrowth

Wealth andincome

Resourceuse

Pollutionand waste

19

81

0.1

1.6

85

15

88

12

75

25

Most fertility rates are dropping toward replacement levels

Strategies for Controlling GrowthStrategies for Controlling Growth Public Public

AdvertisementsAdvertisements Economic Economic

IncentivesIncentives Legal PunishmentsLegal Punishments Empowering Empowering

WomenWomen Investments in Investments in

Education and Education and Family PlanningFamily Planning

Growth Is SlowingGrowth Is Slowingbut still growingbut still growing

ReviewReview

What are problems associated with What are problems associated with rapid human population growth?rapid human population growth?

Compare developed and developing Compare developed and developing (lesser developed) countries.(lesser developed) countries.

Investigate strategies for reducing Investigate strategies for reducing population growth.population growth.

Terms: arable land, urbanization, Terms: arable land, urbanization, suburban sprawl, developed and suburban sprawl, developed and developing countriesdeveloping countries..