Pop

ula

tion

Pyra

mid

s:

Sh

ap

es

Session

4

Shape: TriangularGrowth: Fast

Shape: Extended Triangle

Growth: Moderate

Shape: ColumnGrowth: Slow

Shape: Reduced Pentagon

Growth: Shrinking

• Thomas Malthus – 1798 wrote “Essay on the Principle of Population” • Theory:

• People need food to survive and have natural desire to reproduce

• Food production increases arithmetically and population increases exponentially

• Conclusion:• Predicted population growth would

eventually outpace people’s ability to produce food leading to mass starvation and famine

Time Resources Needed

Today 1 person-1 unit of food

25 years from now 2 persons-2 units of food

50 years from now 4 persons- 3 units of food

75 years from now 8 persons- 4 units of food

100 years from now 16 persons-5 units of food

Malth

us a

nd

Overp

op

ula

tion

Session

4

• Neo-Malthusians argue that 3 characteristics of recent population growth makes Malthus’ argument even more frightening• Sustainability: As the world

approaches 10 billion people, ecological problems will make food demand difficult to meet

• Increasing Per Capita Demand: Amount of food per person is rising MDC citizens consume eight times the amount someone in an LDC consumes

• Natural Resource Depletion: Over-consumption of resources other than food may lead to an insufficient supply when the population hits 10 billion

Paul Erlich – most prominent neo-

Malthusian. Wrote “Population Bomb”

Neo-M

alth

usia

ns

Session

4

• The disastrous end to humanity predicted by Malthus did not occur according to his critics for the following reasons:• Invention: Food production increased because

of tractors, artificial fertilizer, pesticides, irrigation techniques, plant and animal hybridization, refrigeration and canning• Family Planning: Malthus did not foresee

family planning and birth control and leading to a drop in CBR and NIR• Scarcity/Distribution: Malthus did not

recognize that famine is usually NOT related to a lack of food but to unequal distribution of food

Malth

us a

nd

Overp

op

ula

tion

Session

4

• Carrying Capacity: The number of people a given area can maintain• If surpassed, the population must

decline unless the carrying capacity is raised.

• Overpopulation, therefore, implies a breach of an area’s carrying capacity, due to…• Over consumption of resources• Inefficient allocation of goods• Unsustainable land use

• MDC’s blame LDC’s for having too many babies while LDCs blame MDCs for consuming disproportionate share of world’s resources

Carry

ing

Cap

acity

Session

4

• The stages of the Epidemiological Transition Model follows the same path as the Demographic Transition Model.

• Stage 1: Pestilence and Famine• Infectious diseases run rampant killing a large number of the population

• Stage 2: Receding Pandemics• Improved sanitation, nutrition, medicine decreases spread of infectious

diseases

• Stage 3: Degenerative and Human Created Diseases• Fewer deaths from infectious diseases but an increase in

chronic disease associated with aging (heart disease and cancer)

• Stage 4: Delayed Degenerative Diseases • Degenerative diseases linger but life expectancy is extended

through medical advances (bypass, radiation, chemo, etc.)

• Stage 5?: Reemergence of Infectious and Parasitic Diseases• Evolution of new strains of bacteria (TB, polio, malaria) that

are diffused faster due to globalization with a select few able to pay for the treatment

Ep

idem

iolo

gic

al Tra

nsitio

n

Mod

el

Session

4

Video

• Directions:• There is no video guide,

but students are expected to write down 5 impressions and/or questions that they have from the documentary.

Session

2

Ch

ina’s

Lost G

irls

http://www.snagfilms.com/films/title/chinas_lost_girls