Population Review
Ch. 2
Population Big Ideas
Density – Arithmetic, Physiological, & Agricultural
Demographic Transition Model
Epidemiological Transition Model
Populationpatterns – fastest growing and
negative growth countries
Population
pyramids – replacement rate,
dependency ratio, demographic equation, sex
ratio
Malthus and Neo-Malthusians – carrying capacity
Population policies
Ecumene
The portion of the earth with
permanent human
settlement.
Hasexpanded to cover most of
the world’s land area
Population Density
Arithmetic Density
Total number of people divided by total land.
Enables comparisons of the # of people trying to live on a given
piece of land in different regions of the world.
Physiological Density
Number of people supported by a unit area of arable land
Agricultural Density
Ratio of the number of farmers to the amount of arable land.
Helps to account for economic differences
J-Curve & S-Curve
J-Curve
Population projection show exponential
growth. If the population grows exponential
our resource use will go up exponentially, as
well as a greater demand for food and more.
S-Curve
Traces
the cyclical movement upwards and
downwards in a graph.
Components of Population Growth
Demographic Transition Model
Measure population change
Crude Birth Rate (CBR) – total number of live births in a year
for every 1000 people
Crude Death Rate (CDR) – total number of deaths in a year
for every 1000
Rate
of Natural Increase (RNI) – percentage by which a
population grows in a year
Doubling time (the number of years needed to double the
population) is affected by RNI
TotalFertility Rate (TFR) – avg. number of children a woman
will have in her child bearing years.
Stages of the Demographic Transition Model
Stage Birth Rates Death Rates Natural Increase
1 High High Virtually no long term natural increase
2 High Rapid decline Very high natural increase
3 Rapid decline Decline Natural increase begins to moderate
4 Very low Very low Virtually no long-term natural increase
w/possible decrease
What countries
fit in these
stages?
Crude Birth Rate
Life expectancy
Rate of Natural Increase (RNI)
Also known as Natural increase rate
Epidemiological Transition Model
Abdel Omran 1971
Disease vulnerability shifts in
patterns similar to the
demographic transition model.
Stage 1 = Black Plague
Stage 2 = Cholera
Stage 3 = Chronic disorders
Stage4 = Longer life
expectancies
Population Patterns
Areas of high and low
population density are
unevenly spread across the
world.
The majority of places
with high population
density are found in the
northern hemisphere.
Population Pyramids
Chartsthat show the percentages of each age group in the
total population, divided by gender.
For poorer countries, the chart is shaped like a pyramid
Infant mortality rates are higher; life expectancy is shorter.
Population Pyramids
A population pyramid shows lots of different information
about a countries population
• Population in people &
as a % of men
• Population in people &
as a % of women
• Population by age group
(every 5 years if
grouped together)
• Population of men &
women by age group
How to read a population pyramid
First,
determine if the pyramid is measuring in millions of
people or as a percent of the population.
Second, what are you being asked?
About women, men, or the total population? Of a certain age group,
several ages grouped together, or all together?
Finally, identify what you can infer from the pyramid.
Level of development
Major events in the country’s history
EX:War would be represented by several age groups next to each other where
there are many more women than men
EX:A time of celebration may show a population spike, like the Baby Boom of
the late 40s & 50s in the US
Population pyramid
Developed, Developing, Middle Income
Developing tend to have a triangular
shape
Low life expectancy; Steady % of each age
dying off; High birthrates
Developed have more of a block base
No decrease in age groups until roughly 60;
Better medical care
Middle Income take parts of both of
these
Block through 30-35; Steady decrease with
every group after.
Components of Population pyramids
Replacement Rate
Total
Fertility Rate at which girls would have an average of
exactly one daughter over their lifetimes.
Dependency Ratio
Measure showing the number of dependents (aged 0-14 & over
the age of 65) to the total population (age 15-64)
Demographic equation
Increase
or decrease in the population (births – deaths) +/- the
amount of migration to the demographic area
Sex Ratio
Ratio of males to females in a population
Thomas Malthus
Influential in the fields of
political economy and
demography
An Essay on the Principle of
Population
Basic premise: The population is
growing exponentially
(geometrically), however, the
food supply only increases
arithmetically (linear)
Carrying Capacity
Maximum population size that the environment can
sustain indefinitely, given the food, habitat, water,
and other necessities available in the environment.
Neo-Malthusian
Advocate for population control programs,
to ensure resources for current and future
populations.
Boserup
Challenged Malthus’s conclusion
Suggested that food production can, and will,
increase to match the needs of the
population
Malthus’ critics
Many consider his beliefs too pessimistic
Theory was based on idea that world’s supply
of resources is fixed rather than expanding.
Disagree that population increase is not a
problem
Larger
populations could stimulate economic
growth, and therefore, production of more
food.
Population Policies
Expansive population policies
Encourages population growth
Eugenics population policies
Favors one racial or cultural sector over others.
Restrictive population policies
Range from toleration of unapproved birth control to
outright prohibition of large families.
Expansive policy – Europe
Sweden & Norway – Range of policies designed to help
couples have more children
Poland – pay women for each new child they have.
Eugenicspolicy – key program was cleansing the human
race by sterilizing the unfit.
Nazi Europe WWII era – Jews, Gypsy, Unfit, Poles, etc.
Restrictive policy – China and India
China – One-child policy. Restricts the number of children
married urban couples may have.
India– population and family planning. Cases of government
enforced sterilization
Influence of health & well-being
Closely related to location & geography
Infectiousdiseases – invasion of parasites and their
multiplication in the body
Malaria (vectored) – transmitted by an intermediary vector (mosquito)
AIDS (nonvectored) – direct contact between host & victim
Chronic/Degenerative Diseases
Afflictions
of middle and old age – heart disease, cancer, stroke,
pneumonia, diabetes, etc.
Genetic/Inherited Diseases
Disorders that are transferred from one generation to the next.
Metabolic diseases – Lactose intolerance, PKU (Phenylketonuria)
