© 2011 Pearson Education, Inc. Unit 2: Population & Migration Where do people live and how did they get there?

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Where do people live and how did they get there?

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Chapter 2 looks at Population◦ Demography: Geographic word for defining where people

live and how are they distributed according to age, gender, occupation, fertility, health, etc.

Chapter 3 focuses on Relocation diffusion◦ Migration is a specific kind of relocation diffusion where

people move permanently from one place to another Why are these topics crucial and relevant?

◦ 1 More people are alive at this time than at any other point in history (over 7 Billion)

◦ The greatest population growth is happening in LDCs (Less Developed Countries)

◦ The changing scale generated by modern transportation systems makes migration more feasible than in the past

◦ MDCs (More Developed Countries) are experiencing increased rates of immigrants, both legal and illegal

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Population ConcentrationsSparsely Populated RegionsPopulation Density

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Population concentrations◦ Two-thirds of the world’s population are in four regions:

1. East Asia: ¼ of the World’s Population live here – 5/6s of the people in this concentration live in China, the most populous country.

2. South Asia: Nearly ¼ of the world’s population live here as well, in India, Pakistan, Bangladesh, and Sri Lanka. India has 3/4s of the population in this concentration

3. Europe: Including Russia, this is the 3rd largest concentration of people in 4 dozen countries

4. Southeast Asia: World’s 4th largest concentration with 6 million people on the various islands between the Indian Ocean and the Pacific

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Figure 2-2

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The Ecumene◦ From the Greek: “The inhabited Universe”◦ Today’s usage: Environments where World

Civilizations have settled Sparsely populated regions

◦ People generally avoid: Dry lands Wet lands Cold lands High lands

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The Portion of the earth occupied by permanent human settlement

It has expanded from the Middle East and East Asia to encompass most of the world’s land area

Figure 2-4

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Population density◦ Arithmetic density: total number of objects in

an area (Ch. 1) also: Total number of people divided by land area (Ch. 2)

◦ Physiological density : regionally, total number of people supported by a unit of arable land

◦ Agricultural density: ratio of numbers of farmers to the amount of arable land

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Table 2-1

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Natural IncreaseFertilityMortality

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Natural increase rate◦ 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 Doubling time

◦ The number of years needed to double a population

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Figure 2-8

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Fertility◦ Total fertility rate (TFR) measures the total births in

a society. (Average number of children a woman will have through her childbearing years, 15-49)

Mortality◦ Infant mortality rate (IMR) measures the annual

number of deaths of infants under 1 year of age, compared to live births.

◦ Life expectancy measures the average number of years a newborn can expect to live at current mortality levels.

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• Notice that places with high TFRs tend to have high IMRs and that places with low TFRs have low IMRs.

Figure 2-13

Figure 2-14

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• The Demographic Transition• Population Pyramids• Countries in different stages of

the demographic transition• Demographic Transition and

world population growth

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Demographic transition: The model Geographers use to discuss the growth and development countries go through. While countries grow and change in unique ways, all countries experience similar stages in development◦ Four stages

Stage 1: Low growth Agricultural revolution

Stage 2: High growth Industrial Revolution

Stage 3: Moderate growth Stage 4: Low growth

Zero population growth (ZPG)

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Figure 2-15

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Population pyramids◦ A bar graph showing a place’s age and sex

composition◦ Shape of the pyramid is determined mainly

by the CBR◦ Age distribution

Dependency ratio: people too young or old to work

◦ Sex distribution Sex ratio: Number of males per hundred females

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Figure 2-19

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Countries are in different stages of the demographic transition◦Three examples:

Cape Verde = High growth Stage 2 since the 1950s

Chile = Moderate growth Stage 3 since the 1960s

Denmark = Low growth Stage 4 since the 1970s

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Demographic transition & world population growth◦Most countries = stage 2 or stage 3 of

the Demographic Transition Stages 2 and 3 are characterized by significant

population growth◦No country is in stage 1 of the

demographic transition◦It is easier to cause a drop in the CDR

than in the CBR

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• Malthus on Overpopulation

• Declining Birth Rates• World Health Threats

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Malthus on overpopulation◦ An Essay on the Principle of Population

(1798): Population grows geometrically while food supply grows arithmetically: People are increasing faster than the food supply

◦ Criticism of Malthus includes the following: Pessimistic viewpoint: the idea that the world’s

resources is fixed rather than expanding (possiblism)

Failure to consider technological innovation More people means more brains for developing

good ideas Marxist critique: Poverty, hunger, and other social

welfare problems are a result of unjust social and economic institutions, not population growth

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Figure 2-25

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Declining birth rates◦ Reasons for declining birth rates

Reliance on economic development: wealthier communities tend to spend money on education and healthcare

Distribution of contraceptives Women tend to attend school and stay in school

longer resulting in more economic control, and more reproductive choices

Reducing birth rates with contraceptionRapid diffusion of contraceptive methods

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Figure 2-30

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World health threats◦ The epidemiologic transition focuses on distinctive

causes of death in each stage of the demographic transition. Epidemiology: the study of distribution, incidence and control of diseases prevalent among populations at specific times that are not natural to the environment (Example: The 1918 Spanish Flu)

The epidemiologic transition Stage 1: Characterized by pandemics brought about by

infectious and parasitic diseases Malthus referred to these as “natural checks” for growth of the human population The Black Plague or The Bubonic Plague: fleas and rats from

trading ships during the late Middle Ages/early Renaissance

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The epidemiologic transition

Stage 2: Receding pandemics During the Industrial

Revolution improved Sanitation and new medical discoveries increases Life Expectancy Cholera and

Dr. John Snow (The Ghost Map by Steve

Johnson is a fabulous treatment of this event)

Figure 2-31

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The epidemiologic transition Stage 3: Degenerative and human created diseases

Decreased deaths from infectious diseases Increased deaths from chronic disorders associated with

aging Higher instance of man made diseases: diabetes, cancer

Stage 4: Delayed degenerative diseases Medical advances prolong life

Most significant: Heart disease and cancer People still die from disease but due to medical advancements

they can live longer or be cured all together Increasing health and longevity is also a result of behavioral

changes in human populations Better diet and exercise Reduced use of alcohol and tobacco products

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The epidemiologic transition A possible stage 5: Reemergence of infectious diseases?

A set back in a long process of controlling infectious diseases Three reasons why it might be happening:

Evolution: Infectious disease microbes have evolved and changed in response to environmental pressures by developing resistance to drugs and medicines (Ex. Malaria vs. disease resistant mosquitos)

Poverty: In LDCs high instances of poverty usher in the renewal of illnesses related to poverty and industrialization. (Ex. T.B.)

Improved travel: People traveling world wide and bringing new diseases home have seen a huge increase in the rapidity with which new diseases spread around the globe (Ex. Swine Flu)

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Figure 2-33

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Up next: MigrationFigure 3-1