population lecture

7/31/2019 Population Lecture

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Chapter Two

Population


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Distribution of World Population

Population concentrations The four largest population clusters

Other population clusters

Sparsely populated regions Dry lands Cold lands

Wet lands High lands

Population density Arithmetic density

Physiological density

Agricultural density


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World Population Cartogram

Fig. 2-1: This cartogram displays countries by the size of their population rather than

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


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World

PopulationDistribution

& ClimateZones

Fig. 2-2: World population is unevenly distributed across the earths surface.

Climate is one factor that affects population density.


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World Population Density


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Climate Zones (simplified)


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Expansion

of theEcumene5000 BC -AD 1900

Fig. 2-3: The ecumene, or the portion of the

earth with permanent humansettlement, has expanded to covermost of the worlds land area.


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Ecumene, 5000 B.C.


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Ecumene, A.D. 1


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Ecumene, A.D.1500


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Ecumene, A.D.1900


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Arithmetic Population Density

Fig. 2-4: Arithmetic population density is the number of people per total land area.

The highest densities are found in parts of Asia and Europe.


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Physiological Density

Fig. 2-5: Physiological density is the number of people per arable land area. Thisis a good measure of the relation between population and agricultural

resources in a society.


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Measures of Population Density


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Distribution of World

Population Growth Natural Increase

Fertility Mortality


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World Population Growth1950 - 2005

Fig. 2-6: Total world population increased from 2.5 to over 6 billion in slightly over 50years. The natural increase rate peaked in the early 1960s and has declined

since, but the number of people added each year did not peak until 1990.


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Crude Death Rates

Fig. 2-12: The crude death rate (CDR) is the total number of deaths in a country per1000 population per year. Because wealthy countries are in a late stage ofthe Demographic Transition, they often have a higher CDR than poorer

countries.


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Natural Increase Rates

Fig. 2-7: The natural increase rate (NIR) is the percentage growth or decline in thepopulation of a country per year (not including net migration). Countries inAfrica and Southwest Asia have the highest current rates, while Russia and

some European countries have negative rates.


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Life Expectancy at birth

Fig. 2-11: Life expectancy at birth is the average number of years a newborn infant canexpect to live. The highest life expectancies are generally in the wealthiestcountries, and the lowest in the poorest countries.


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Variations in Population Growth

The Demographic Transition 1. Low growth 3. Moderate growth

2. High growth 4. Low growth

Population pyramids Age distribution

Sex ratio

Countries in different stages of demographictransition

Demographic transition and world populationgrowth


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The Demographic Transition

Fig. 2-13: The demographic transition consists of four stages, which move from highbirth and death rates, to declines first in death rates then in birth rates, andfinally to a stage of low birth and death rates. Population growth is mostrapid in the second stage.


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World Population & Growth

Rates,400,000 BC - AD 2000


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Demographic Transition in England

Fig. 2-14: England was one of the first countries to experience rapid population growth inthe mid-eighteenth century, when it entered stage 2 of the demographic

transition.


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Percent of Population under 15

Fig. 2-15: About one-third of world population is under 15, but the percentage by countryvaries from over 40% in most of Africa and some Asian countries, to under 20%in much of Europe.


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ElderlyShoppersin Russia


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Population Pyramids in U.S. cities

Fig. 2-16: Population pyramids can vary greatly with different fertility rates (Laredo vs.Honolulu), or among military bases (Unalaska), college towns (Lawrence), and

retirement communities (Naples).


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Census taking in China


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Rapid Growth in Cape Verde

Fig. 2-17: Cape Verde, which entered stage 2 of the demographic transition in about1950, is experiencing rapid population growth. Its population historyreflects the impacts of famines and out-migration.


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Moderate Growth in Chile

Fig. 2-18: Chile entered stage 2 of the demographic transition in the 1930s, and it

entered stage 3 in the 1960s.


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Low Growth in Denmark

Fig. 2-19: Denmark has been in stage 4 of the demographic transition since the1970s, with little population growth since then. Its populationpyramid shows increasing numbers of elderly and few children.


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Will the World Face anOverpopulation Problem?

Malthus on overpopulation

Population growth & food supply

Malthus critics

Declining birth rates

Malthus theory & reality

Reasons for declining birth rates

World health threats

Epidemiological transitions


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Fuel Wood Collection in Mali


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Crude Birth Rate Decline, 1980-2005

Fig. 2-21: Crude birth rates declined in most countries during the 1980s and 1990s(though the absolute number of births per year increased from about 120 to130 million).


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Use of Family Planning

Fig. 2-22: Both the extent of family planning use and the methods used vary widely by

country and culture.


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Women Using Family Planning


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Family Planning Methods

used in three countries


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Promoting One-Child Policy in China


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CholerainLondon,

1854

Fig. 2-23: By mapping the distribution of cholera cases and water pumps in Soho, London,Dr. John Snow identified the source of the water-borne epidemic.


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Tuberculosis Death Rates

Fig. 2-24: The tuberculosis death rate is good indicator of a countrys ability to invest in

health care. TB is still one of the worlds largest infectious disease killers.


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Avian Flu, 2003 - 2006

Fig. 2-25: The first cases of avian flu in this outbreak were reported in Southeast Asia.


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Retired Man in Russia

population lecture

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