Section 3: Population Patterns and Processes

What caused the Irish Potato Famine?

English colonial practices forced Irish farmers to prioritize growing potatoes, so when a fungus called potato blight spread through farms, Irish people lost their primary source of nutrition

Within which latitude lines do people tend to live?

Between 65 degrees North and 45 degrees South of the Equator

How does the topography of a region affect its population size?

Areas with flat land tend to have higher populations than mountainous regions

Chain migration

When immigrants move to a new place to follow specific family members or link with an existing community

What factors influence the development of settlement clusters in a region?

• Its topography

• Access to sources of water

• Human activity(e.g. are their jobs available?)

• Soil quality

What are the three categories of population density?

• Arithmetic density

• Physiological density

• Agricultural density

Arithmetic density

Density calculated by dividing the population of a place by its total land area

What does arithmetic density show?

How crowded an area is

Physiological density

Density calculated by dividing the population of an area by its farmable land

What does physiological density show?

Whether the resources in an area can sustain its population

Agricultural density

Density calculated by dividing the number of farmers in an area by its total farmable land

What does agricultural density show?

How much labor is required to support food systems in a location

Subsistence farming

When farmers grow crops and raise livestock to feed themselves and their families. It is more common in developing countries and leads to a higher agricultural density

Rural-urban migration

The movement of people from rural areas to urban centers

Ethnic enclaves

Densely populated areas with immigrants who share an ethnic or cultural identity

Dependency ratio

The ratio of population who are too old or too young to support themselves to the working-age population(typically shown as n:100)

Age structure

How a population is distributed across age groups

Carrying capacity

The population limit a place’s natural resources can support sustainably

Population composition

The characteristics of people who live in an area

Population pyramids

Models that show the age-sex ratio of a particular population

What does a swell in the middle of a population pyramid indicate

An economic boom and a large future aging pool

Demographic Transition Model(DTM)

A model of demographic stages that represents a progression from high birth rates and death rates to low birth rates and death rates over time

Total Fertility Rate(TFR)

The average number of children born to a woman who survives her childbearing years

Why do developing countries tend to have higher total fertility rates

People in these regions often prize having many descendants due to cultural traditions, and families can benefit from the value of their children’s labor

Why do more developed countries tend to have lower total fertility rates

Easy access to contraceptives

Crude Birth Rate(CBR)

The annual births per thousand people in a population

Crude Death Rate(CDR)

The annual deaths per thousand people in a population

Infant Mortality Rate(IMR)

The percentage of children in a population who do not survive their first year of life

Natural Increase Rate(NIR)

The difference in the annual number of births and deaths within a country

Doubling Time

The time it takes for a population to double in size

What parts of the population does the Natural Increase Rate not consider

• Immigrants

• Emigrants

• Migrant laborers

The Rule of 70

Doubling time = 70 / NIR

Net migration

number of immigrants - number of emigrants

Net in-migration

When the number of immigrants exceeds the number of emigrants

Net out-migration

When the number of emigrants exceeds the number of immigrants

Push factors

Negative conditions that cause people to leave their home country/region

Pull factors

Positive conditions that encourage immigration to a place

Forced migration

When people are forced to leave their homelands by dire conditions, such as war or disease

Epidemiological Transition Model(ETM)

A model that represents a progression from high mortality rates from poverty and infectious diseases, to low mortality rates from chronic, degenerative diseases like heart disease and cancer

What are the 5 stages of the Demographic Transition Model?

• High stationary stage: high CBR and high CDR(little fluctuation in population counts)

• Early expanding stage: high CBR and declining CDR(rapid population increase)

• Late expanding stage: declining CBR and low CDR(rapid urbanization and industrialization)

• Low stationary stage: low CBR and low CDR(little fluctuation in population counts)

• Declining stage: low CBR and increasing CDR

Pronatalist policies

When governments, typically in countries in the declining stage of the DTM, encourage people to have children by offering incentives like maternity leave, subsidized childcare, and tax rebates

What does the population pyramid look like for countries in the declining stage of the DTM?

A narrow base and broader top, forming an inverted triangle shape

What are the five stages of the Epidemiological Transition Model?

• Pestilence and famine: high death rate from infectious, and usually preventable, diseases(high IMR and short life expectancy)

• Receding pandemics: mortality from infectious disease falls(IMR drops significantly and life expectancy improves)

• Degenerative and human-created diseases: diseases characteristic of aging populations play the biggest role in the country’s mortality and people focus on lifestyle changes to improve life expectancy

• Delayed degenerative diseases: chronic diseases are the main cause of death but there is a high life expectancy from healthcare improvements

• Reemerging infectious diseases: