Human PopulationHuman Population

Chapter 9Chapter 9

Studying Human PopulationsStudying Human Populations Demography is the study of the Demography is the study of the

characteristics of populations. characteristics of populations. Dependent on:Dependent on:- historical size historical size - makeup of the populationsmakeup of the populations- properties that affect population properties that affect population

growth:growth:• economics economics • social structuresocial structure

Chapter 9

Grouped into Two CategoriesGrouped into Two Categories

Developed countries:Developed countries: have higher average incomes, slower have higher average incomes, slower

population growth, diverse industrial population growth, diverse industrial economies, and stronger social support economies, and stronger social support systems.systems.

Developing countriesDeveloping countries have lower average incomes, simple and have lower average incomes, simple and

agriculture-based economics, and rapidagriculture-based economics, and rapid population growth.population growth.

World Population over timeWorld Population over time

World PopulationWorld Population Exponential growth in the Exponential growth in the

1800’s1800’s Increased each decadeIncreased each decade Due to the Industrial and Due to the Industrial and

Scientific RevolutionScientific Revolution Due to Increases in food Due to Increases in food

productionproduction Due to Improvements in Due to Improvements in

hygienehygiene

Age StructureAge Structure Age structure - Age structure - is the classification of is the classification of

members of a population into groups members of a population into groups according to age used for demographicsaccording to age used for demographics

Countries that have Countries that have high rateshigh rates of growth of growth young people > older people.young people > older people.

Countries that have Countries that have slow growthslow growth or no or no growth Young = Oldgrowth Young = Old

Age-Structure DiagramsAge-Structure Diagrams

Chapter 9Section 1 Studying Human Populations

SurvivorshipSurvivorship Survivorship Survivorship is the percentage of newborn is the percentage of newborn

individuals in a population that can be expected to individuals in a population that can be expected to survive to a given age.survive to a given age.

Type IType I survivorship - Wealthy survivorship - Wealthy developed countries developed countries such as Japan and Germanysuch as Japan and Germany have a curve because mosthave a curve because most people live to be very old. people live to be very old.

Type IIType II - populations equal - populations equal death rate at all ages.death rate at all ages.

Type IIIType III survivorship -is the survivorship -is the pattern in very poor humanpattern in very poor human populations in which many children die.populations in which many children die.

Fertility Rates Fertility Rates Number of babies born each year/1000 womenNumber of babies born each year/1000 women Replacement level – number of children that Replacement level – number of children that

must be born to each parent to “replace” must be born to each parent to “replace” themselves in a population 2.1themselves in a population 2.1

Baby boom vs Baby bustBaby boom vs Baby bust Fertility rates in the US are below replacement Fertility rates in the US are below replacement

level but population continues to grow due to level but population continues to grow due to baby boomersbaby boomers

Migration – movement of people between areasMigration – movement of people between areas Immigration – movement into an areaImmigration – movement into an area Emigration – movement out of an areaEmigration – movement out of an area Many developed countries populations would Many developed countries populations would

be decreasing without immigrationbe decreasing without immigration

Fertility RatesFertility Rates

Chapter 9Section 1 Studying Human Populations

Life ExpectancyLife Expectancy Most affected by infant mortality rateMost affected by infant mortality rate Developed vs Undeveloped countriesDeveloped vs Undeveloped countries Declining death rate due to vaccinesDeclining death rate due to vaccines

Demographic TransitionDemographic Transition1st Stage – pre-industrial condition, birth and

death rate high -> population stable 1700’s2nd Stage – population explosion due to

improvements in hygiene, nutrition, education3rd Stage – population growth slows as birth rate

decreases4th Stage – birth rate drops below replacement

level, population decreases

Stages of the TransitionStages of the Transition

Life ExpectancyLife Expectancy

The graph below shows The graph below shows that average life that average life expectancy worldwide expectancy worldwide has increased to more has increased to more than 67 years old. But, than 67 years old. But, new threats, such as new threats, such as tuberculosis and AIDS tuberculosis and AIDS are arising as populations are arising as populations become denser.become denser.

Chapter 9

Women and FertilityWomen and Fertility Factors that affect declining birth ratesFactors that affect declining birth rates 1. Increasing education1. Increasing education 2. Economic independence2. Economic independence

Developed vs developing countriesDeveloped vs developing countries Large families to care for family and Large families to care for family and

farmfarm Smaller families due to parents working Smaller families due to parents working

away and cost of child careaway and cost of child care

Changing Population TrendsChanging Population Trends Infrastructure -Infrastructure - is the basic facilities of a is the basic facilities of a

country or region such as roads, bridges, country or region such as roads, bridges, sewers, power plants, subways, schools, sewers, power plants, subways, schools, and hospitals.and hospitals.

A rapidly growing population uses resources A rapidly growing population uses resources at an increased rate and can overwhelm the at an increased rate and can overwhelm the infrastructure of a community thus causing infrastructure of a community thus causing environmental problemsenvironmental problems

Symptoms of overwhelming populations Symptoms of overwhelming populations include suburban sprawl, polluted rivers, include suburban sprawl, polluted rivers, barren land (logging), inadequate housing, barren land (logging), inadequate housing, and overcrowded schools.and overcrowded schools.

A Shortage of FuelwoodA Shortage of Fuelwood In many of the poorest countries, wood is the In many of the poorest countries, wood is the

main fuel source.main fuel source.

When populations are stable, people use fallen When populations are stable, people use fallen tree limbs for fuel. When populations grow tree limbs for fuel. When populations grow rapidly, deadwood does not accumulate fast rapidly, deadwood does not accumulate fast enough to provide enough fuel.enough to provide enough fuel.

People then begin cutting down living trees, People then begin cutting down living trees, which reduces the amount of wood available in which reduces the amount of wood available in each new yeareach new year..

Chapter 9

A Shortage of FuelwoodA Shortage of Fuelwood A supply of fuel ensures that a person A supply of fuel ensures that a person

can boil water and cook food.can boil water and cook food.

In many parts of the world, water taken In many parts of the world, water taken directly from wells is not safe to drink. directly from wells is not safe to drink. Food is often unsafe to eat unless it is Food is often unsafe to eat unless it is cooked.cooked.

Water can be sterilized, and food can be Water can be sterilized, and food can be cooked, but fuel is need to do so. cooked, but fuel is need to do so. Without enough fuelwood, many people Without enough fuelwood, many people suffer from disease and malnutrition.suffer from disease and malnutrition.

Unsafe WaterUnsafe Water In places that lack infrastructure, the local water In places that lack infrastructure, the local water

supply may be used not only for drinking and supply may be used not only for drinking and washing but also for sewage disposal.washing but also for sewage disposal.

As a result, the water supply becomes a breeding As a result, the water supply becomes a breeding ground for organisms that can cause diseases ground for organisms that can cause diseases such as dysentery, typhoid, and cholera.such as dysentery, typhoid, and cholera.

Many cities have populations that are doubling Many cities have populations that are doubling every 15 years, and water systems cannot be every 15 years, and water systems cannot be expanded fast enough to keep up with this expanded fast enough to keep up with this growth.growth.

Impacts on LandImpacts on Land

Growing populations may have a shortage Growing populations may have a shortage of arable land.of arable land.

Arable landArable land - is farmland that can be used - is farmland that can be used to grow crops.to grow crops.

Growing populations also make trade-offs Growing populations also make trade-offs between competing uses for land such as between competing uses for land such as agriculture, housing, or natural habitats.agriculture, housing, or natural habitats.

Chapter 9

Impacts on LandImpacts on Land For example, Egypt has a population of For example, Egypt has a population of

more than 69 million that depends on more than 69 million that depends on farming within the narrow Nile River valley.farming within the narrow Nile River valley.

Most of the country is desert, and less than Most of the country is desert, and less than 4 percent of Egypt’s land is arable.4 percent of Egypt’s land is arable.

The Nile River Valley is also where the jobs The Nile River Valley is also where the jobs are located, and where most Egyptians live. are located, and where most Egyptians live. They continue to build housing on what was They continue to build housing on what was once farmland, which reduces Egypt’s once farmland, which reduces Egypt’s available arable land.available arable land.

Impacts on LandImpacts on Land Urbanization Urbanization is an increase in the ratio or is an increase in the ratio or

density of people living in urban areas rather density of people living in urban areas rather than in rural areas.than in rural areas.

People often find work in the cities but move People often find work in the cities but move into suburban areas around the cities.into suburban areas around the cities.

This suburban sprawl leads to traffic jams, This suburban sprawl leads to traffic jams, inadequate infrastructure, and reduction of land inadequate infrastructure, and reduction of land for farms, ranches, and wildlife habitat. for farms, ranches, and wildlife habitat. Meanwhile, housing within cities becomes more Meanwhile, housing within cities becomes more costly, more dense, and in shorter supply.costly, more dense, and in shorter supply.

A Demographically Diverse A Demographically Diverse WorldWorld

Not every country in the world is progressing Not every country in the world is progressing through each stage of demographic transition. through each stage of demographic transition.

Some countries now have modern industries, Some countries now have modern industries, but incomes remain low. A few countries have but incomes remain low. A few countries have achieved stable and educated populations with achieved stable and educated populations with little industrialization.little industrialization.

Some countries seem to remain in the second Some countries seem to remain in the second stage and are unable to make enough stage and are unable to make enough educational and economic gains to reduce birth educational and economic gains to reduce birth rates and move into the third stage.rates and move into the third stage.

A Demographically Diverse A Demographically Diverse WorldWorld

In recent years, the international community In recent years, the international community has begun to focus on the least developed has begun to focus on the least developed countries.countries.

Least developed countriesLeast developed countries are countries that are countries that have been identified by the united Nations as have been identified by the united Nations as showing the fewest signs of development in showing the fewest signs of development in terms of income, human resources, and terms of income, human resources, and economic diversity.economic diversity.

These countries may be given priority for These countries may be given priority for foreign aid and development programs to foreign aid and development programs to address their population and environmental address their population and environmental problems.problems.

A Demographically Diverse A Demographically Diverse WorldWorld

Populations are still growing rapidly in Populations are still growing rapidly in less developed countries, with most of less developed countries, with most of the world’s population now within Asiathe world’s population now within Asia..

Managing Development and Managing Development and Population GrowthPopulation Growth

Today, less developed countries face the Today, less developed countries face the likelihood that continued population growth will likelihood that continued population growth will prevent them from imitating the development of prevent them from imitating the development of the world’s economic leaders.the world’s economic leaders.

Countries such as China, Thailand, and India Countries such as China, Thailand, and India have created campaigns to reduce the fertility have created campaigns to reduce the fertility rates of their citizens.rates of their citizens.

These campaigns include public advertising, These campaigns include public advertising, family planning programs, economic incentives, family planning programs, economic incentives, or legal punishment.or legal punishment.

Managing Development and Managing Development and Population GrowthPopulation Growth

In 1994, the United Nations held the In 1994, the United Nations held the International Conference on Population and International Conference on Population and Development (ICPD), Development (ICPD),

It involved debates about the relationships It involved debates about the relationships between population, development, and the between population, development, and the environment.environment.

Many countries favor stabilizing population Many countries favor stabilizing population growth through investments in development, growth through investments in development, especially through improvements in women’s especially through improvements in women’s status.status.

Managing Development and Managing Development and PopulationPopulation

With these goals, worldwide fertility With these goals, worldwide fertility rates are dropping as shown below.rates are dropping as shown below.

Growth Is SlowingGrowth Is Slowing Fertility rates have declined in both more-Fertility rates have declined in both more-

developed and less-developed regions. developed and less-developed regions.

Demographers predict that this trend will Demographers predict that this trend will continue and that worldwide population continue and that worldwide population growth will be slower this century than the growth will be slower this century than the last century.last century.

If current trends continue, most countries If current trends continue, most countries will have replacement level fertility rates by will have replacement level fertility rates by 2050. If so, world population growth would 2050. If so, world population growth would eventually stop.eventually stop.

Looking at the graph below, most Looking at the graph below, most demographers predict the medium growth rate, demographers predict the medium growth rate,

and a world population of 9 billion in 2050.and a world population of 9 billion in 2050.