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
1965 AD
3200 million
1990 AD
5300 million
2020 AD
8230 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 childrencould 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
Total
Fertility
Rate
Lowest
(W.
Europe)
Lowest
(E.
Europe)
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
120
7
22
2.9%
0.1%
-0.4%
Infant
Mortality
Rate per
1000
Annual
Growth
Rate
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
Types of Age Structure Diagrams
Stable Populations
• Birth rates = death
rates
• All age groups are
about equal
• EX: Most Western
European countries,
U.S.
Types of Age Structure Diagrams
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 Control
Please 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 childrenorphans
• 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.