• “Dot movie” – http://www.youtube.com/watch?v=4BbkQiQyaYc

• Population time-line – http://www.pbs.org/wgbh/nova/worldbalance/numbers.html

Human Geography

Studying Population

Objectives

• Where do people live and why?

• Why do populations rise and fall in particular places?

• How does the geography of health influence population dynamics?

• How do governments affect population change?

How do geographers study population?

• Geographers use demography- statistical study of human populations

Population DensityPopulation Density Arithmetic Population Density – the total number of

people divided by the total land area (This measure is also called population density.) Arithmetic density enables geographers to make approximate comparisons of the number of people trying to live on a given piece of land in different regions of the world.

There is no relationship between arithmetic density and standard of living.

area

population=

people per square mile

Arithmetic Population DensityArithmetic Population Density

Arithmetic population density is the number of people per total land area.The highest densities are found in parts of Asia and Europe.

United States Population Density

319,030,322

3,541,447 mi2=

90 people per square mile

3,855,103 mi2

34,300,083 =

for Canada:

for China:

1,355,692,576

=3,705,407 mi2366 people per

square mile

9 people per square mile

China vs. Canada

Physiologic DensityPhysiologic Density

A more meaningful population measure is by looking at the number of people per area of a certain type of land in a region.

The number of people supported by a unit of arable land is called the physiologic population density.

Comparing physiologic and arithmetic densities helps geographers to understand the capacity of the land to yield enough food for the needs of people.

Physiologic DensityPhysiologic Density

Physiological density is the number of people per arable land area. This is good measure of the relation between population and agricultural resources in a society.

Agriculture DensityAgriculture Density

Two countries can have similar physiological densities, Two countries can have similar physiological densities, but they may produce different amounts of food but they may produce different amounts of food because of different economic conditions. because of different economic conditions. Agriculture Agriculture density density is the ratio of the number of farmers to the is the ratio of the number of farmers to the amount of arable land. amount of arable land.

The Netherlands has a much higher physiological The Netherlands has a much higher physiological density than does India but a lower agriculture density.density than does India but a lower agriculture density.

Agriculture density is directly related to standard of Agriculture density is directly related to standard of livingliving

Measures of DensityMeasures of Density

Do you know…Write your best guess.

1. What is the world population?

2. How many people live in the United States?

3. What is the population of Texas?

4. What is the population of San Antonio?

The Census

• The census is a count of everyone living in the United States every 10 years.

• The census is required by the U.S. Constitution.

• The last census was in 2010.

• Your participation in the census is required by law.

• The first Census was conducted in 1790 and has been carried out every 10 years since then.

Population DistributionPopulation DistributionAreas that are sparsely inhabited- People generally avoid:

Dry lands (areas too dry for farming = 20 %)Cold lands (permafrost!)Wet lands (close to equator: rain + heat = nutrients

depleted from the soil) High lands (highest mtns. are steep and snow-covered)

Expansion of the EcumeneExpansion of the Ecumene 5000 B.C.–A.D. 1900 5000 B.C.–A.D. 1900

The ecumene, or the portion of the Earth with permanent human settlement, has expanded to cover most of the world’s land area.

Studying Population

Natural Increase – the percentage by which a population grows in a year

Crude birth rate (CBR) – the number of births per 1,000 population

Crude death rate (CDR) – the number of deaths per 1,000 population

Total fertility rate (TFR) - the number of children an average woman in a society will have through her childbearing years.

Infant mortality rate - the number of infant deaths per 1,000 live births per year.

Life expectancy at birth - the average number of years a newborn infant can expect to live.

Population Reference Bureau

• http://www.prb.org/Publications/Datasheets/2015/2015-world-population-data-sheet/world-map.aspx#map/world/births/imr

Natural Increase RatesNatural Increase Rates

The natural increase rate (NIR) is the percentage growth or decline in the population of a country per year (not including net migration).

Studying Population

United States 1960 2006 2012

Birthrate (per 1000)

23.7 14.3 13.7

Death rate (per 1000) 9.5 8.1 8.4

Natural Increase 14.2 6.2 5.3

Crude Birth RatesCrude Birth Rates

The crude birth rate (CBR) is the total number of births in a country per 1,000 population per year.

Crude Death RatesCrude Death Rates

The crude death rate (CDR) is the total number of deaths in a country per 1,000 population per year.

Total Fertility RatesTotal Fertility Rates

The Total fertility rate (TFR) is the number of children an average woman in a society will have through her childbearing years. The lowest rates are in

Europe, and the highest are in Africa and parts of the Middle East.

Infant Mortality RatesInfant Mortality Rates

The infant mortality rate is the number of infant deaths per 1,000 live births per year. The highest infant mortality rates are found in some of the poorest

countries of Africa and Asia.

Life Expectancy at birthLife Expectancy at birth

Life expectancy at birth is the average number of years a newborn infant can expect to live. The highest life expectancies are generally in the wealthiest

countries, and the lowest in the poorest countries.

Population Reference Bureau

• http://www.prb.org/pdf15/2015-world-population-data-sheet_eng.pdf

• http://www.prb.org/Publications/Datasheets/2015/2015-world-population-data-sheet/world-map.aspx#map/world/population/pop65

Doubling TimeDoubling Time• Doubling Time of a population (years) :

– 70 / Population Growth Rate (%)

( 70 / 2.0% = 35 years )

– Rule of 70 :determine how long it would take for a population to double at its present growth rate.

– divide 70 by the population’s annual growth rate to determine the years needed to double the size of the population.

Human Population Doubling TimeHuman Population Doubling Time

30

World Population CartogramWorld Population Cartogram

This cartogram displays countries by the size of their populationThis cartogram displays countries by the size of their population rather than their land area. rather than their land area.

(Only countries with 50 million or more people are named.)(Only countries with 50 million or more people are named.)

Warm-up: Wednesday

• Use the statistics to answer the following questions:

1. What country is projected to be the most populous by 2050?

2. What continent has the top 12 highest fertility rates?

3. Where does the majority of the world’s population live? (more developed or less developed countries?)

4. Compare the population data of more developed countries and less developed countries.

Critical Issues in Population Critical Issues in Population GeographyGeography

• More people are alive today than at any More people are alive today than at any other time in human history.other time in human history.

• The worldThe world’’s population increased at a s population increased at a faster rate during the second half of the faster rate during the second half of the 2020thth century than ever before. century than ever before.

• Virtually all population growth today Virtually all population growth today occurs in less developed countries occurs in less developed countries (LDCs)(LDCs)

World Population Growth, 1750–2150World Population Growth, 1750–2150

Source: United Nations, World Population Prospects, The 1998 Revision; and estimates by the Population Reference Bureau.

http://www.youtube.com/watch?v=9_9SutNmfFk&feature=BF&list=ULadYPZ59_AUc&index=1

Demographic Transition Model

• What is a model?– a representation of some phenomenon of

the real world made in order to facilitate an understanding of its workings

– a simplified and generalized version of real events, from which the incidental detail has been removed

Demographic Transition Model

• When using this model, what is not considered when looking at population growth?

Stage 1 Stage 2 Stage 3 Stage 4 Stage 5

Birth Rate

Death Rate

Natural Increase

Reasons for changes in birth rate

Reasons for changes in death rate

Stage 1: High Stationary

• Applied to most of the world before the Industrial Revolution

• Both birth rates and death rates are high

• As a result, population size remains fairly constant but can have major swings with events such as wars or pandemics.

Stage 1

• Stage 1 of the Demographic Transition Model is considered the pre-industrial stage, or pre-transition, and today no countries are classified within Stage 1 of the DTM. This is quite a feat given that for all of human history up until the 18th Century, all countries were considered within Stage 1.

Stage 2: Early Expanding

• The introduction of modern medicine lowers death rates, especially among children, while birth rates remain high; the result is rapid population growth.

• Many of the least developed countries today are in Stage 2.

Stage 3: Late Expanding

• Birth rates gradually decrease, usually as a result of improved economic conditions, an increase in women’s status, and access to contraception.

• Population growth continues, but at a lower rate.

• Most developing countries are in Stage 3.

Stage 4: Low Stationary

• Birth and death rates are both low, stabilizing the population.

• These countries tend to have stronger economies, higher levels of education, better healthcare, a higher proportion of working women, and a fertility rate hovering around two children per woman.

• Most developed countries are in Stage 4.

Stage 5: Declining?

• A possible Stage 5 would include countries in which fertility rates have fallen significantly below replacement level (2 children) and the elderly population is greater than the youthful population.

Demographic Transition Model: The 5-stage Demographic Transition Model: The 5-stage versionversion

• Limitations of the Demographic Transition Model

• Like any model, there will be outliers and exceptions to the rule and the Demographic Transition Model is no different. Additionally, there are things the DTM cannot reveal: the impact of other demographic variables such as migration, are not considered, nor does the model predict how long a country will be in each stage. But even so, the relationship between birth rate and death rate is an important concept when discussing population and any patterns, such as those provided by the DTM, that aid in understanding are helpful.

Let’s look at a few countries …

• Sketch the Demographic Transition Model on the white board. Then use the stats to put a dot where each country lies.

• US– Crude Birth Rate: 12.49– Crude Death Rate: 8.15

• Germany– CBR: 8.47– CDR: 11.42

• Nigeria– CBR: 37.64– CDR: 12.9

• Papua New Guinea– CBR: 24.38– CDR: 6.53

• Japan– CBR: 7.93– CDR: 9.51

• Saudi Arabia– CBR: 18.51– CDR: 3.33

Warm-up: Thursday

• According to this graph, what happens to population in the long-term?

PopulationPopulation PyramidsPyramids

Understanding Population Pyramids

• http://ed.ted.com/lessons/population-pyramids-powerful-predictors-of-the-future-kim-preshoff

On the left side you can see the number of men in each age group and on the right you can see the same information for women.

What is a “cohort”?

What age group has the greatest difference in number between men and women?

Nigeria is a country in west Africa with much less wealth and economic development than the USA.

What are some of the differences between the populations of Nigeria and the United States? What might be some possible reasons for this?

While there is subtle differences in the shape of the two pyramids there is one MAJOR difference that will mean big challenges for India’s future. What is it?

Afghanistan is country in Central Asia which has experienced non-stop war over the last 30 years.

The USA and its allies invaded Afghanistan in 2001 in response to the Afghanistan’s government support of terrorism.

How will the population change over the next 30 years?

What will have to be built to accommodate this growth?

Japan, unlike Afghanistan, has enjoyed tremendous prosperity and economic growth since the end of WWII.

These two pyramids show one of the problems Japan is facing today and will certainly have to address in its future.

How is Japan’s challenges different from Afghanistan’s?

* Rapid growth

Copy the information

Population Pyramids in U.S. CitiesPopulation Pyramids in U.S. Cities

Population pyramids can vary greatly, with different fertility rates (Laredo vs. Honolulu), or among military bases (Unalaska), college towns

(Lawrence), and retirement communities (Naples).

• Explain this!