Demographic Transition- The process of a change in society’s populations from a condition of high crude birth rate, and death rates and low rates of natural increaser to a condition of low crude birth rate and death rates, low natural increase, and a higher total population.

Crude Birth Rate (CBR) - The total number of live births in a year for every 1,000 people alive in a society.
Crude Death Rate (CDR) - total number of deaths in a year for every 1,000 people in a society.
Natural Increase Rate (NIR) (also referred to as the Rate of Natural Increase (RNI) and Natural increase Rate (NIR) - Percent growth of a population in a year, computed as CBR minus CDR.
Total Fertility Rate (TFR) - the average number of children a woman will have in her child bearing years, highlighted as being higher in stage 2 countries of the demographic transition model.
Zero population growth- Decline of the Total Fertility Rate (TFR) to the point where the natural increase rate equals zero.
Replacement Rate- The degree to which a population is replacing itself, based on the ratio of the number of female babies to the number of women of childbearing age.
Agricultural revolution- The time when humans first domesticate plants and animals and no longer relied on hunting and gathering techniques. This allowed human to create settlements, and began the specialization of labor.
Industrial revolution- A series of improvements in industrial technologies that transformed the process of manufacturing goods. 1750.
Medical revolution- Improvements and diffusion of medical technology from Europe and North America to less developed countries of Africa, Asia, and Latin America.

Stage 1- Low Growth // High Stationary Phase
Low amounts of growth due to the way food was gathered as hunter gatherers.
High crude death rates and high crude birthrates
NIR was stagnant and roughly zero.
Famines were a main reason for death
High rate infant mortality (death before age 1 per 1,000 of a population)
Hunter Gather stage- which was hunting and gathering food, before the first agricultural revolution for sustenance.
First Agri Rev occurs in this stage but no dramatic increase in population
No country exists in this current stage of demographic transition.

Stage 2- High Growth // Early Expanding Phase
High NIR
Increases in medicine and technologies facilitated growth.
Median ages around the late teens.
Countries entered stage 2 after 1750 as a result of the industrial revolution, and the late twentieth century medical revolution.
Also corresponds with second agricultural revolution
Crude Birth Rate remains high.
Crude Death Rate declines
Largest growth stage

The problem of stage two is that it can provide a demographic trap, which occurs when the population grows too quickly for the country to support, and this results in developmental problems within the country (ex. Population increases to the point where 3 schools are needed, only one opens)

Reasons for the high growth include a rural lifestyle, fear of children dying (high IMR), male dominated societies, lack of opportunities (economic and education)

Example of stage two countries would exist in Sub-Saharan? Africa.

Stage 3- Moderate Growth // Late Expanding Phase
Moderate growth due to a lowering of the Total Fertility Rate (TFR), a result of increased education levels, and opportunities for women.
Crude Death rate continues to decline and stabilize
Crude Birth Rate declines sharply - that marks this phase from 2.
Median age would be in the mid to late 20s
NIR is still high, promoting population growth, but there is much less significant growth than in stage two.
Population continues to increase as a result of higher CBR than CDR.
Asia takes advantage of the 3rd agri rev helping them maintain their population

People now have more opportunities, are increasingly growing up in an urban lifestyle and the lowering of the CDR decreases fears of children dying before adulthood

States that reach this stage tend to continue towards development

Examples of stage 3 are prevalent in Latin America (Brazil, Mexico) and Asia.

Stage 4- Low Growth
Low Growth due to a decline in Total Fertility Rate
Crude Birth Rate is low
Crude Death Rate is low
Median ages would be in the 30s.
CBR in stage four countries decline to the point where it equals the crude death rate, and the natural increase rate equals zero.
Countries approach Zero Population Growth (ZPG)
Countries in many cases (Europe) have a negative natural increase rates, as they are below replacement rate.

Alternative lifestyles are more accepted here. For example, LATs, YUPPIES, and DINKs as well as homosexuality.

The countries have people that have lived for a generation or more in an urban environment, women with as many opportunities as men, and are more popular than traditional folk culture. Jobs are increasingly post-industrial.

Examples of stage 4 would include the United States (only stage 4 country above replacement rate), Europe, Australia, and Japan.

Migration Patterns - The Migration Transition
People within stage 2 and 3 countries are increasingly moving to the cities. Stage 2 countries are the most rapidly urbanizing because they are the most rural and have the highest possibility of people moving to the cities. This is the largest migration path currently happening in the world today.

People from stage 2 and 3 countries are moving to the MDCs of stage 4 because those countries offer opportunities that their crowded countries cannot.

Stage 4 countries have migration patterns that are primarily internal and usually have people going from one urban area to another. People are highly mobile within their countries. These countries are also source areas for migrants from stage 2 and 3

Note: The largest reason for migration is economic. People in the LDCs move to the MDCs in search of jobs and they also move from rural to urban in search of jobs.