Chapter 2 PopulationThis is a featured page

Key Issue #1: Where is the world’s population distributed?

Population Concentrations -Chey
Among the industrialised nations of the world, the USA has a relatively short history of urbanisation. This fact and the ready availability of reliable historical data have made the USA a fertile place for studying the nature of urban and regional growth from its earliest beginnings. This paper analyses the patterns of city and hinterland, or city-system, population concentration in the United States from 1790 to 2000. The Hoover index is employed to calculate population concentration in 46 city-systems for each federal census. A model showing three phases in city-system population concentration is proposed. Recent population trends are then used to map the current concentration phases of the US city-systems. Much of the central part of the country and the mountain west should concentrate in population during the next decade while many of the Northeastern, Florida, and Californian city-systems are more likely to experience population deconcentration.

An effect of the loss of diversity and the rapid concentration of an initially broadly spread population is analyzed for models of phenotypic evolution. The impact of the population size, different selection schemes, and dimensionality of the search space on population diversity is studied. Obtained results confirm common opinions that in large populations the diversity is greater and that the stronger selection pressure causes the faster concentration. High dimensional search spaces do not restrain the concentration of a population. In this case, populations cluster even faster than in one-dimensional search space.

2010 Arizona Projected Population Concentration Map:

U.S. Population Concentration:

Sparsely Populated Regions - Chey
Least Populated Countries:
World Top Ten Least Populated Countries Map

Sparsely Populated Areas in Europe (inhabitants per square kilometer):
Chapter 2 Population - AP Human Geography @ GPHS 2008
This map displays only areas with low or very low population density in Europe. Most parts of Norway, Sweden, Finland, the Baltic, Northern Scotland and Central Spain have population densities of below 30 inhabitants per square kilometer. Areas with such a low population density can be certainly classified as predominantly rural. Low population density of under 60 inhabitants per square kilometer can be also found in large parts of Ireland, Central and Southern France, Eastern Germany, Northern and North-eastern Poland, the southern part of the Czech Republic, Slovakia, Hungary, Austria, Bulgaria, the western part of Romania, and Greece.

Comprehension Questions
1. What part of the country is projected to concentrate in population in the next decade?
2. What factors are analyzed to model phenotypic evolution?
3. Which Arizona Municipal Planning Area is projected to have the greatest population concentration by 2010?
4. What is the U.S. population percent change from April 1st, 2000 to July 1st, 2000?
5. What is the least populated country in the world?

Population Density - Sierra

Population Density
Population Density- is a measurement of population per unit area or unit volume
  • Population density refers to the number of individuals per square kilometer of land area
  • It is a common biological measurement and is more often used by conservationists as a measure than population size
  • Commonly this may be calculated for a county, city, country, another territory, or the entire world
  • The world population is 6.6 billion
  • Earth's area is 510 million square kilometers (200 million square miles)
  • Therefore the worldwide human population density is 6.6 billion / 510 million = 13 per km² (33 per sq mi), or 43 per km² (112 per sq mi) if only the Earth's land area of 150 million km² (58 million sq mi) is taken into account
population density

Key Issue #2: Where has the world’s population increased?

Natural Increase - Sierra

Fertility - Ashley
Geographers use the total fertility rate (TFR) to measure the number of births in society. The TFR is the average number of children a woman will have thoughout her childbearing years
The TFR for the whole world is 2.7, and, again, the figures vary between MDCs and LDCs.
Image:Fertility rate.jpg

The Crude Birth Rate (CBR) and Crude Death Rate (CBR) are statistical values that can be utilized to measure the growth or decline of a population.
The Crude Birth Rate and Crude Death Rate are both measured by the rate of births or deaths respectively among a population of 1000. The CBR and CDR are determined by taking the total number of births or deaths in a population and dividing both values by a number to obtain the rate per 10000. For example, if a country has a population of one million and 15,000 babies were born last year in that country, we divide both the 15,000 and 1,000,000 by 1000 to obtain the rate per 1000. Thus the Crude Birth Rate is 15 per 1000

Chapter 2 Population - AP Human Geography @ GPHS 2008

Mortality – Ashley
The infant mortality rate is the annual number of deaths of infants under 1 year of age compared with the total number of live births
Chapter 2 Population - AP Human Geography @ GPHS 2008

Life expectancy at birth measures the average number of years a newborn infant can expect to live at current mortality levels
Chapter 2 Population - AP Human Geography @ GPHS 2008

Key Issue #3: Why is population increasing at different rates in different countries?

The Demographic Transition - Sheik

The demographic transition is a process of change in a society’s population from a condition of high crude birth and death rates and a low rate of natural increase to a condition of low crude birth and death rates, low rate of natural increase, and a higher total population.

The demographic transition has several stages and every country is in one of them. The process has a beginning, middle and end.

Stage 1: Low Growth
Most of humanity’s several-hundred-thousand-year occupancy of the earth was characterized by stage one of the demographic transition. During most of this period, people depended on hunting and gathering food. When food was easily obtained, a regions population increased, but it declined when people were unable to locate enough animals of vegetation nearby. At about 8000 B.C, the world’s population began to grow by several thousand per year. From about 8000 B.C to 1750 A.D the world’s population grew fro, 5 million to 800 million. That was sparked by the agricultural revolution.
Chapter 2 Population - AP Human Geography @ GPHS 2008Chapter 2 Population - AP Human Geography @ GPHS 2008

Stage 2: High Growth
For 10,000 years the world’s population grew at a modest pace. After around 1750 the world’s population suddenly began to grow 10 times faster than it did in the past. The world population grew about 5 million in 1800 compared to only about ½ a million in 1750. Countries entered stage 2 of the demographic transition after 1750 as a result of the industrial revolution. The industrial revolution was a conjunction of major improvements industrial technology (stem engine, mass production, powers transportation).new machines helped farmers increase agricultural production and feed the rapidly growing populations.
Chapter 2 Population - AP Human Geography @ GPHS 2008

Stage 3: Moderate Growth
European and North American countries moved from stage 2 to 3 in the first half of the 20th century. A society moves to stage 3 when people choose to have fewer children. Economic changes on stage 3 societies also induce people to have fewer offspring’s. People in stage 3 are more likely to live in cities rather than in the countryside, and to work in offices, shops, or factories rather than on framers.
Chapter 2 Population - AP Human Geography @ GPHS 2008

Stage 4: Low Growth
A country reaches stage 4 of the demographic transition when the C.B.R declines to the point where it equals the C.D.R, and the N.I.R approaches zero. That is called zero population growth. Women in stage 4 societies enter the labor force rather than remain at home as full tome house wife’s.
Chapter 2 Population - AP Human Geography @ GPHS 2008

what sparked stage 1 of the demographic transition?
what started stage 2 of the demograhic transition
which countrys are in stage 4?

Warren Thompson [His Contribution and Theories on Demographic Transition} - Sheik
Warren Thompson created the demographic transition model in 1929(DTM). It is a model used to explain the process of shift from high birth rates and high death rates to low birth rates and low death rates as part of the economic development of a country from a pre-industrial to an industrialized economy. It is based on prior observed changes, and transitions, in birth and death rates in industrialized societies over the past two hundred years that Thompson noticed.

who created the demographic trantition model?
when was the model created?
what was the model based on what observations?

Population Pyramids - Eric
A population pyramid normally shows the percentage of the total population in 5-years age group,with the youngest group 0 to 4 years old at the base of the pyramid and the oldest group at the top.The length of the bar represents the percentage of the total population contained in that group.By convention,males are usually shown on the left side of the pyramid and females on the right. The shape of the pyramid is determined primarily by the CBR in the community.A country in stage 2 of the demographic transition,with a high CBR,has a relatively large number of young children,making the base of the population pyramid very broad.On the other hand a country in stage 4 with a relatively large number of older people has a graph with a wider top that looks more like a rectangle than a pyramid.
Image:China population pyramid 2005.png
Population pyramid of China

Population pyramid of United States

Image:Angola population pyramid 2005.png
Population pyramid of Angola

Countries in Different Stages of Demographic Transition - Eric

Demographic Transition and World Population Growth. - Elliot
All countries have experienced some changes in natural increase, fertility, qnd mortality rates, but at different times and at different rates. Although rates vary among countries, a similar process of change in society's population, known as demographic transition, is operating. Because of diverse local cultural and economic condition, the demographic transition diffuses to individual countries at different rates and produces local variations in natural increase, fertility, and mortaliy.

The demographic transition is a process with several stages, and every country is in one of them. The process has a beginning, middle, and end, and--barring a catstrophe such as a nuclear war--it is irreversible. Once a country move from one stage of the process to the next, it does not revert to an earlier stage.

Stage 1: Low Growth
Most of humanity's several-hundred-thousand-year occupancy of Earth was characterized by stage 1 of the demographic transition. Crude birth and death rates varied considerably from one year to the next and from one region to another, but over the long term they were roughly comparable, at very high levels. As a result, the NIR was essentially zero, and Earths's population was unchanged, at perhaps a half a million.

Stage 2: High Growth
Some demographers divide stage 2 of the demographic transition into two parts. The first part is the period of accelerating population growth. During the second part, the growth rate begins to slow, although the gap between births and deaths remains high.

Stage 3: Moderate Growth
A country moves from stage 2 to stage 3 of the demographic transition when the CBR begins to drop sharply. The CDR continues to fall in stage 3 but at a much slower rate than in stage 2. The population continues to grow because the CBR is still greater than the CDR. But the rate of natural increase is more modest in countries in stage 3 than in those in stage 2 because the gap between the CBR and the CDR narrows.

Stage 4: Low Growth
A country reaches stage 4 of the demographic transition when the CBR declines to the point where it equals the CDR, and the NTR approaches zero. This condition is called zero population growth, a term often applied to stage 4 countries.

Worldwide population increased rapidly during the second hallf of the twentieth century because few countries were in a two stages of the demographic transition that have low population growth--no country remains at 1, and few have reached stage 4. The overwhelming majority of countries are in either stage 2 or stage 3 of the demographic transition--stages with rapid population growth--and only a few are likely to reach stage 4 in the near future.

Key Issue #4: Why might the world face an overpopulation problem?

Malthus on Overpopulation - Elliot

English economist Thomas Malthus was one of the first to argue that the world's rate of population increase was far outrunning the development of food supplies. His views remain influential today. In 1798, Malthus claimed that the population was growing much more rapidly than Earth's food supply because population increased geometrically, whereas food supply increased arithmetically. According to Malthus, these growth rate would produce the following relationships between people and food in the future:

  • Today: 1 person, 1 unit of food
  • 25 years from now 2 persons, 2 units of food
  • 50 years from now 4 persons, 3 units of food
  • 75 years from now 8 persons, 4 units of food
  • 100 years from now 16 persons, 5 units of food
Malthus made these conclusions several decades after England had become th first country to enter stage 2 of the demograhic transition, in association with the Industrial Revolution. He concluded that population growth would press against available resources in every country, unless "moral restraint" produced lower CBR's or uness disease, famine, war, or other disasters produced higher CDR's.

Declining Birth Rates - Catherine

Some regions with rapid population growth do face food shortages.

Malthus Theory and Reality

Even though the human population has grown at its most rapid rate ever, world food production has consistently grown at a faster rate than the natural increase rate (NIR).

  • Food production increased during the last half of the 20th centurymore rapidly than Malthus predicted.
  • Better growing techniques, higher-yielding seeds, and cultivation of more land helped the food supply.
  • Malthus predicted population growth to go from 2.5 billion to 10 billion, but the world population is only 6 billion.

World Population

Reasons for Declining Birth Rates: lower birth rates or higher death rates.

  • Some countries of sub-Saharan Africa have increasing crude death rates (CDR).
  • The crude birth rates (CBR) has declined rapidly from 27-21 in the world, from 15-10 in more developed countries (MDC), and 31-24 in less developed countries (LDC).
  • 2 strategies have helped reduce birth rates: reliance on economic development and distribution of contraceptives.
Economic Development

  • One way to lower birth rates is to emaphasize the importance of improving local economic conditions.
  • A wealthier community has more money to spend on education and health-care programs that promotes lower birth rates.
  • If more women are able to attend school and remain there, they are likely to gain employment and perspective on giving birth.
  • With improved health-care programs, infant mortality rates (IMR) would decline.
  • With the survival of more infants ensured, women would be more likely to use contraceptives.
Chapter 2 Population - AP Human Geography @ GPHS 2008
Infant Mortality vs Gross Domestic Product (GDP)

Distribution of Contraceptives

  • Another way to lower birth rates is diffusing the idea of contraceptives.
  • Putting resources into family-planning programs can reduce birth rates rapidly.
  • In LDCs, the demand for contraceptives are greater than what can be supplied. So, they need to be distributed among them cheaply and quickly.
  • The percentage of women using contraceptives in Africa is very low. Reasons: economics, religion, education.
  • Many oppose birth-control programs for religious and political reasons.
  • Many oppose abortion; U.S. advise countries they have aided in family-planning to advise abortion.

The most effective means of reducing births would be by using both economic development and contraceptives.


What are some factors that have contributed to rapid food production?
What are two strategies that help reduce birth rates?
What are some ecomomic developments that reduce birth rates?
Why are women that go to school and remain there, more likely to reduce birth rates?
Why do some people oppose using contraceptives?

World Health Threats - Catherine

Medical researchers have identified an epidemiologic transition that focuses on distinctive causes of death in each stage of the demographic transition.

Epidemiologic Transition Stages 1 and 2

Stage 1- the stage of pestilence and famine

  • Infectious and parasitic diseases, and accidents and attacks by animals and other humans were principal causes of deaths (called natural checks)
  • Most violent Stage 1 epidemic: the Black Plague (bubonic plague), which was transmitted by fleas from migrating infected rats.
  • The plague spreaded from the coaast to inland towns and then to rural areas.
  • About 25 million Europeans died between 1347 and 1350, at least 1/2 of the continent's population.
  • In China, 13 million died from the plague.
  • The plague wiped out entire villages and families.

Image:Black Death.jpg
Effects of the Black Plague

Image:Bubonic plague-en.svg
Spread of the Black Plague in Europe

Stage 2- the stage of receding pandemics; improved sanitation, nutrition, and medicine during the Industrial Revolution reduced the spread of infectious diseases

  • Poor people crowded into cities and had high death rates.
  • Cholera became a virilent epidemic in urban areas during the Industrial Revolution.
  • 1/2 million people died of cholera in New York City.
  • Residents of poorer neighborhoods had a much higher incidence of cholera and other diseases and died at a younger age.
  • Many believed that the people with disease were being punished for their sinful behavior and that moost victims were poor because povery was a sin.
  • Cause: contaminated sewage was getting into the water supply of a pump that happened to be used by a cluster of poor people.
  • Construction of water and sewer systems domolished cholera by the late 19th century.

Cholera in Afghanistan

20080910_boy_washing_in_stream_new_born_child_infected_with_cholera_Hashimiyah_hospital_2panel by Gorillas Guides.
Cause and Effect of Cholera

Epidemiologic Transition Stages 3 and 4

Stage 3- the stage of degenerative and human-created diseases; an increase in chronic disorders associated with aging

  • 2 important chronic disorders are cardiovascular diseases and different forms of cancer.
  • Polio cases have declined from 39,000 to 6,000 worldwide.
  • Fatalities from measles for children under the age of 15 declined.
  • Effective vaccines were responsible for these declines.
  • In LDCs, infectious diseases have also declined.

Stage 4- the stage of delayed degenerative diseases

  • The major degenerative causes of death, cardiovascular diseases and cancers, linger, but the life expectancy is extended through medical advances.
  • Reducement factors: medicine slows or can remove cancer, bypass surgery repairs deficiencies in the cardiovascular system, behavior changes (better diets, exercise, reduced use of tobacco and alcohol).

Epidemiologic Transition Possible Stage 5

Stage 5- the reemergence of infectious and parasitic diseases

  • Reasons to explain emergence of stage 5: Evolution- infectious disease microbes have continuously evolved and changed in response to environmental pressuresby developing resistance to drugs and insecticides. Poverty- diseases cause many deaths in LDCs. Improved travel- motor vehicles allow rural residents to easily reach urban areas and urban residents to reach rural areas. Airplanes give access to other countries. People carry diseases with them and are exposed to the diseases of others.
  • Many new infectious diseases have emerged over the past 3 decades and have spread through travel.
  • Avian flu or bird flu had infected 258 people in 2006, which was transmitted from birds.
  • Epidemiologists believed that it wasn't spread easily or contagious, but that it might turn into a pandemic.
  • to know if a disease was pandemic, it would break out simultaneously in many locations.
  • The most lethal epidemic in recent years is AIDS (acquired immunodeficiency syndrome).
  • Worldwide, 20 million people died of AIDS in 2006 and 40 million were living with HIV (human immunodeficiency virus).
  • 95% of people living with HIV and 99% of new cases have come from LDCs.
  • Sub-Saharan Africa had 2/3 of the world's total HIV-positive population and 9/10 of the world's infected children.
  • 2nd highest rate of infection was in Caribbean countries.
  • Crude death rates rose as a result of AIDS, and life expectancy has declined.

Snowball Effect of AIDS

Suffering/Effects of AIDS


What are the 5 stages of epidemiologic transition?
Name a disease that falls under each stage.
What is the cause of cholera?
What is the cause of avian flu (bird flu)?
What are 3 reasons for the reemergence of infectious and parasitic diseases?

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