1. Population Pyramids and Demographic Transition Model
Population changes over time and space.
2. Population change can be shown on two models.

2. The population pyramid displays the age
POPULATION STRUCTURE
The population pyramid displays the age
and sex structure of a country or given area
OLD DEPENDANTS
ECONOMICALLY
ACTIVE
YOUNG
DEPENDANTS
Population in
Five Year
Age bands
FEMALES
To the right
MALES
To the left
Usually, but not always,
in % to make for easier
comparisons
between countries

3. What Population Pyramids Show Us
KEY
The overall shape of the population pyramid can indicate whether it is an
Economically More Developed Country or Economically Less Developed Country
Economically
More
Developed
Country
Less
slope of pyramid indicate the death rate
height of graph can indicate life expectancy (ignore the very thin end of the wedge as occurs on graph B as these people are a definite minority)
proportions of men and women can suggest male or female migrations
"kinks" indicate dramatic reductions in birth rate or increases in death rate in the past
width of the base is related to birth rate/fertility rate
area of graph indicates total population - compare areas of different population age groups or different sex on one graph

5. The DTM (Demographic Transition Model)
The three key components to pay attention to in the Demographic Transition Model are:
Birth Rates
Death Rates
Total Population
The vertical on the graph is rate per 1000 and the horizontal is time.

6. Demographic Transition
Demographers call the sequence of stages in population growth the demographic transition model.
The FOUR stages are:
Low-Growth Stage - HIGH birth rate and HIGH death rate lead to a population that varies over time, with little long-term population growth.
High-Growth Stage - HIGH birth rate and DECLINING death rate lead to sustained and significant population increase.
Moderate-Growth Rate – DECLINING birth rate combined with already-low death rate lead to continuing population growth.
Low-Growth or Stationary Stage - LOW birth rate and LOW death rate lead to a very LOW rate of growth.

7. Demographic Transition
The transition in the demographic transition occurs in stages 2 and 3, when death rates decline and then birth rates decline.
When the death rate and birth rate fall, the country transitions from a high growth rate to a low or sustained growth rate.

8. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage A
Both high birth rates and death rates fluctuate in the first stage of the population model giving a small population growth (shown by the small total population graph).

9. Stage 1: Low Growth
The low population growth rate of stage 1 is marked by much human suffering. With incredibly high birth rates and equally high death rates, population increases slowly.
Epidemics and plagues keep the death rates high among all sectors of the population.
During the 1300s, the Black Death (bubonic plague) hit Europe in waves beginning in Crimea on the Black Sea, diffusing through trade to Sicily and other Mediterranean islands, and moving through contagious diffusion and the travel of rats (who hosted the vector, the flea, that spread the plague) north from the Mediterranean.
Famines also limited population growth. Records in India and China during the 18th centuries document millions of people perishing.

10. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage B
Birth rates remain high, but death rates fall rapidly causing a high population growth (as shown by the total population graph).

11. Stage 2: High Growth
1700s = beginning of the Industrial Revolution. Sanitation facilities made towns and cities safer from epidemics, and modern medical practices diffused.
Disease prevention through vaccination introduced a new era in public health.
Also marks the Second Agricultural Revolution – more efficient farming methods decreased the number of people needed in farming and the food supply increased, thereby supporting a higher population.
1750 = DR in Europe of 35/1000, 1850 = 16/1000
When European and North American countries moved into stage 2 in the 1800s, their populations took off, inflating worldwide population.
European colonization of Africa and Asia in late 1800s brought those areas into stage 2. New alarms and cautions of worldwide population rang.

12. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage C
Birth rates now fall rapidly while death rates continue to fall. The total population begins to peak and the population increase slows to a constant.

13. Stage 3: Moderate Growth
Europe and North America entered stage 3 in the first half of the 1900s.
Stage 3 is marked by continuing , but slower, decline in death rates coupled with a significant decline in birth rates. The result is continued growth in the population but at a much slower rate.
In the second half of the 1900s, many countries in Latin America and Asia entered stage 3, which has helped slow the global population growth rate.
Why do birth rates decline, allowing a country to move into stage 3?
Low birth rates with greater urbanization, wealth, and medical advances.
Opportunity for women were not compatible with large families, delaying marriage and childbearing.
Medical advances lowered infant and child mortality rates, lessening the sense that multiple children were necessary to sustain a family.
Diffusion of contraceptives, the accessibility to abortions, and woman’s conscious decision to have fewer children at a later age all lower birth rates within a country.

14. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage D
Both birth rates and death rates remain low, fluctuating with 'baby booms' and epidemics of illnesses and disease. This results in a steady population.

15. Stage 4: Low Growth
The countries experiencing exceptionally low TFRs are in the fourth stage of the demographic transition.
Having achieved low (if not too low) birth rates along with low death rates puts the countries in a position of low to zero population growth.
Birth rates are lowest in the countries where women are the most educated and most involved in the labor force.
A country reaches stage 4 when the CBR declines to the point where it equals the CDR, and the NIR approaches zero.
This condition is called ZPG (Zero Population Growth), a term often applied to stage 4 countries.
Italy and France – Western European countries.

16. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage E?
A stage 5 was not originally thought of as part of the DTM, but some northern countries are now reaching the stage where total population is declining where birth rates have dropped below death rates.

17. Future Population Growth
Many agencies suggest most (if not all) countries’ populations will stop growing at some time during the 21st century, reaching a so-called stationary population level (SPL).
This would mean the world’s population would stabilize and the major problems to be faced would involve the aged rather than the young.
In 2004, the United Nations predicted that world population would stabilize at 9 billion in 300 years.

18. Demographic Transition

19. Combining Both Models

20. Population Pyramids related to the Demographic Transition Model
Stage 1
Stage 2
Stage 3
Stage 4
IMPLICATIONS
Both birth rates and
Death rates are
High, so population
growth rates are
slow but population
Is usually restored
Due to high birth
Rate. Short life
Expectancy
EXAMPLES: Afghanistan, Ivory Coast
Population starts
to grow at an
exponential rate due to fall in Crude Death Rate. More living In middle age.
Life expectancy rises
Infant mortality rate falls.
EXAMPLES: Jordan, Thailand
Population continues
to grow but at slower
rate. Low C Death Rate.
Dramatically declining
Crude Birth Rate.
EXAMPLES: Ireland, China, New Zealand
Low Crude Birth Rate
and Crude Death Rate
Higher dependency ratio
and longer life expectancy
Crude Death Rate does
Rise slightly because of
The ageing population
EXAMPLES: United States, Japan
There is some merit in including or considering
a Stage 5 today with a declining population