HUMAN POPULATIONS

HUMAN POPULATIONS

Chapter 4

APES

Pros & Cons of Human Population Growth

• Pros– Larger workforce– More new ideas– Better able to extend

our carrying capacity through development of technology

• Cons– Resource depletion– Environmental

degradation– Pollution– Poverty

Human Population Growth

• Population small before agriculture & domestication of animals

• Until Middle Ages, population limited by famine, disease, wars

• After 1600, sailing/navigation increased commerce

• Around 1800-1900, increases in agricultural development, better energy sources, better health care & hygiene

DATE POPULATION

5000 BC 50 million

800 BC 100 million

200 BC 200 million

1200 AD 400 million

1700 AD 800 million

1900 AD 1600 million




• Will our populations overshoot the carrying capacity & experience dieback?

• Will our population level off… have we even reached our carrying capacity?

Who do you agree with?

• Neo-Malthusian – We are approaching or

have surpassed our carrying capacity.

– We should address the issue of surplus population directly by making birth control our highest priority.

– Named after Thomas Malthus

• Neo-Marxist– Eliminating oppression

and poverty through technological development and social justice will solve population problems.

– Named after Karl Marx

Role of Technology in Population Growth

• Increased availability of resources- fossil fuels

• Increased agricultural productivity

• Increased commerce• Better medicine• Better sanitation

Human Demography

• “Measure of people”• Do not know exact number- many countries do

not take census or census inaccurate• Gov’t may overestimate to make country look

larger or smaller to suit their needs• Current estimate- 6.7 billion people

– 20% live in developed countries– 80% live in developing countries– 90% of population growth will occur in Third World

Countries

• What are the 12 most populous countries in 2025?

• Why do you think India’s population is surpassing China’s?– Population control programs not as successful due to

strict cultural & religious beliefs.• Why has the birth rate decreased and death rate

increased in Russia?– After Soviet Union broke up in 1992, crime,

corruption, disease, hyperinflation, & despair have reduced standard of living

• What has affected the population growth in Africa?– 20-25% of people in Zimbabwe, Bostwana, Zambia, &

Namibia have HIV/AIDS

Fertility & Birthrates

• Crude Birth Rate (CBR)– # of births per 1,000 per year

• Total Fertility Rate (TFR)– # of children born to an

average woman in a population during her entire reproductive life.

• In 17th & 18th century England, babies given to wet nurse so women could recover quicker & produce more children- could have 25-30 pregnancies

• Should total fertility rate be calculated for men, too? – In Cameroon, men have

multiple marriages, affairs, etc. Produce 8 children per lifetime vs. females with avg. of 4.8.

What we want to achieve is…

• Zero Population Growth (ZPG)– Also called Replacement

Level Fertility– # of births to just replace

yourself– Usually 2 children per

couple– Not completely accurate

because some people are infertile, some babies don’t survive, some choose to not have kids

• Fertility rates have declined everywhere except Africa over past 50 years– Ex: In 1975, Mexico’s fertility

rate was 7 children per woman. In 1998, it was 2.5

– China dropped from 6 in 1970 to 1.8 in 1995

– Which regions had the biggest decrease in TFR? W. Pacific & SE Asia

– Which region had the smallest decrease in TFR? Africa

Countries with Highest & Lowest Fertility Rates

• Highest in developing countries such as Africa; Lowest in Europe

• Based on the data table, what conclusions can you draw?

Highest Lowest (W. Europe)

Lowest (E. Europe)

Total Fertility Rate

6.7 1.3 1.4

GNP/capita/year

$225 $19,000 $3108

Life expectancy

47.6 yrs 77.6 yrs 68.9 yrs

Birth Rate per 1000

47.6 9.7 9.9

Death Rate per 1000

17.6 10.0 13.0

Infant Mortality Rate per 1000

120 7 22

Annual Growth Rate

2.9% 0.1% -0.4%

Death Rates

• Crude Death Rates (CDR)– # of deaths per 1000 per

year– Ex: in Africa with poor

sanitation & health care may be 20/1000

– Wealthier countries are about 10/1000

• In a rapidly growing country there are more youths & fewer elderly so fewer deaths

Population Growth Rates

• CBR-CDR = Natural increase in population• Total Growth Rate- includes immigration & emigration• Total Growth Rate =

(CBR + immigration) – (CDR + emigration)• Total Growth Rate of U.S. is higher than natural rate of

increase due to immigration.• Better food & nutrition, has decreased CDR.• People living longer due to better food/nutrition, clean

water, better education, higher income• Some say declining mortality, not rising fertility, is the

primary cause of most population growth

What happens if people start living longer?

• If people start to live until they are 100…

• If people still retire at age 65…

• We will have more people who are retired & unemployed for longer periods which could have an effect on the economy- more social security, government subsidized programs = more government debt.

Age Structure Diagrams

Age Structure• Growing & declining pop. will have very different

proportions of individuals in various age classes.

Types of Age Structure Diagrams

Expanding Population• Young (pre-reproductive)

dominates population• Has population

momentum- more children will move up to become reproductive

• Potential for rapid increase in birth rates once the youngsters reach reproductive age.

• EX: Developing countries- many countries in Africa, Mexico, S. America


Stable Populations• Birth rates = death

rates• All age groups are

about equal• EX: Most Western

European countries, U.S.


Declining Populations• Birth rates are lower

than death rates• Many more older

people who are not reproducing

• Population will become much smaller when they die.

Why do people emigrate or immigrate?

• Seeking political or economic asylum from home country– Wars are prevalent– No jobs or poor economy

• Environmental refugees – no longer able to farm land

due to change in weather/climate

– Homes destroyed by hurricane, tsunamis cause people to flee homes

Immigration/Emigration

• Immigrants are usually paid low wages & live in substandard housing, have fewer rights, or poor working conditions

• Pros- immigrants will perform jobs others will not (dangerous, dirty, physically demanding), bring cultural diversity, ingenuity.

• Cons- taking jobs, overload social services, ignore laws, subjected to hate crimes

Forced Migrations

• Indonesia- 1970’s– Moved 65 million people from

overcrowded islands of Java & Bali to less populated Sumatra, Borneo & New Guinea

– Attempts at farming the rainforest failed

– Ended in economic & environmental disaster

– Rainforests were destroyed & people were no better off.

– Threatened biodiversity of region

Why do people have children?• Pronatalist pressures- factors that

increase a desire to have children– Pleasure & pride in children– Support elderly parents (esp., if no

social security system) – Have more if more likely to die – Status symbol in some cultures- men

are more “manly” if they have more kids

– Continue species– Religious pressures to have children– Pregnant women given special

status/attention– Need son, will produce kids until get

one (or have abortions of girls until they get one) (India)

– Women have no status except as mother/wife- often raped if protest husbands advances

– Ignorant about birth control methods or religion does not allow use

Why are birth rates lower in developed countries?

• Higher education of women• Personal freedom of women• Desire to spend money on

other goods• Earn a salary = less time to

spend @ home & have children

• Women waiting longer to have children

• More money= better health care= more kids survive= fewer you have to have

• Populations tend to boom after a war

What are the drawbacks to a declining birth rate?

• Lack of future soldiers/military• Lack of workers- affects economy, causing

declining social system• Some countries offering incentives to bear

children- Germany, Denmark, Russia, Japan

• In US & Europe can be good – – declining birth rate = less demand on

resources = less pollution

Demographic Transition

• Pattern of falling death rates & birth rates due to improved living conditions.

• Preindustrial societies- food shortages, malnutrition, lack of sanitation & medicine, accidents, other hazards cause higher birth & death rates (30/1000)

• Industrialization- better jobs, more income, more people surviving due to rise in standard of living. Death rates decrease, birth rates increase

• Postindustrial societies- eventually BR & DR level out & population is at equilibrium. W. Europe saw this in 19th & 20th century.

• Many rapidly growing countries are experiencing early stages of demographic transition, but their birth rates are not falling as seen in W. Europe

Key to controlling Population Growth…

• Education & Empowerment of Women– Giving political rights– Opportunities for them to earn income– Improve their health status– Educating them about birth control– Improve families & better able to take care of children

they have so don’t have to have more

• Hopefully this will lead to decreasing birth rates• Saving 5 million children from preventable

communicative diseases will avoid 20-30 million extra births

Family Planning

• Allows couples to determine the # & spacing of children

• Birth control is an essential part of family planning

Methods/Types of Birth ControlPlease note- Mrs. Johnson does not condone or endorse any of these methods- I am just sharing options used by people all over the world. ABSTINENCE IS THE ONLY TRUE WAY TO AVOID

UNWANTED PREGNANCY AND DISEASE!!!

• Avoidance- Abstinence/using rhythm method/ Delayed marriage

• Mechanical barriers- condoms (10% failure rate), spermicides, diaphragm, vaginal sponge

• Surgical methods- tubal ligation, vasectomy• Chemicals- birth control pills, gossypol for males, Norplant

(silicone “matchsticks” of slow release hormone), Depo-Provera (injections), the Patch, vaginal rings- MANY OF THESE HAVE BEEN KNOW TO CAUSE BLOODCLOTS!! BE CAREFUL!!

• Physical Barriers to implantation- IUD• Induced abortions- RU486 (morning after pill) blocks

progesterone so pregnancy cannot be maintained• Future of Birth Control- testing urine for hormones,

biodegradable inserts, antipregnancy vaccines (immunization against chorionic gonadotropin- hormone needed for maintaining pregnancy), birth control pills for men

Incentives & Drawbacks for Population Control

INCENTIVES• Free/more accessible government

subsidized family planning– Free clinic services, free birth control, free

education about birth control• Economic Rewards/Penalties

– Payment for sterilization– Eliminating income tax deductions for more

than one child– Free health care benefits for families with 0-1

child.– Monetary bonus at end of year for 0-1 child.– Free higher education for women with fewer

kids– Increased social security for 0-1 kid families– Government subsidized housing for 0-1 kids– Couples pay a tax for each child after the

first one

DRAWBACKS• Cultural/social issues in some countries• Interferes with religion• Children punished for actions of parents• Fewer workers to support aging community• Lack of military• These programs cost money- who pays?• Difficult to disseminate information or

enforce regulations (few TV’s in rural regions)

• Reduced tax revenue= increased gov’t spending= inflation

• Civil unrest• Emigration/immigration• May not work in rural areas because of the

need for child labor• Increase in # of abandoned children-

orphans• Increase in STD’s, unwanted pregnancies,

etc, that may accompany free birth control

Future of Human Populations

• Most predict we will equalize @ 8-10 billion people

• Some think based on our current estimates our carrying capacity is 15 billion people.

• Obstacles– US Congress refuses to make payments to the UN

Family Planning Fund because 135 countries include abortion as part of their population plan

– Due to diverse religious beliefs it is difficult for United Nations Earth Summit to come to an agreement on Population Growth Prevention.

Documents

HUMAN POPULATIONS