POPULATION STRUCTURE The population pyramid displays the age and sex structure of a country or given area Usually, but not always, in % to make for easier comparisons between countries FEMALES To the right MALES To the left Population in Five Year Age bands OLD DEPENDANTS ECONOMICALLY ACTIVE YOUNG DEPENDANTS Nigeria is a country experiencing rapid population growth and has a high percentage of young people approaching or at child-bearing age. The population pyramid with a wide base reflects the high percentage of young people. Japan, Germany, and Russia are all experiencing zero population growth, which would result in a narrow base on the population pyramid. The United States is experiencing slow population growth resulting in a slightly larger base that remains relatively constant throughout the ages until slightly decreasing at the top of the pyramid

What Population Pyramids Show Us KEY slope of pyramid indicate the death rate width of the base is related to birth rate/fertility rate proportions of men and women can suggest male or female migrations 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) "kinks" indicate dramatic reductions in birth rate or increases in death rate in the past area of graph indicates total population - compare areas of different population age groups or different sex on one graph 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 Economically Less Developed Country

According to the four stages of the demographic transition model, as countries industrialize, birth and death rates decrease over time due to increased access to health care, education (particularly among women), and other social changes

The DTM (Demographic Transition Model) The three key components to pay attention to in the Demographic Transition Model are: 1.Birth Rates 2.Death Rates 3.Total Population The vertical on the graph is rate per 1000 and the horizontal is time. The first stage of the demographic transition model indicates that total population is low and constant due to high birth and death rates. This is common in preindustrial societies where women have many children that help support the household. Population does not increase since death rates remain high due to lack of medical care

Demographic Transition Demographers call the sequence of stages in population growth the demographic transition model. The FOUR stages are: 1.Low-Growth Stage - HIGH birth rate and HIGH death rate lead to a population that varies over time, with little long-term population growth. 2.High-Growth Stage - HIGH birth rate and DECLINING death rate lead to sustained and significant population increase. 3.Moderate-Growth Rate – DECLINING birth rate combined with already-low death rate lead to continuing population growth. 4.Low-Growth or Stationary Stage - LOW birth rate and LOW death rate lead to a very LOW rate of growth. Stage four of the demographic transition model experiences low birth rates since women are being educated and economies are not dependent on child labor

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.

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). In general, positive checks result in higher death rates while preventive checks result in lower birth rates. Disease, war, famine, and disasters are examples of positive checks. Moral restraint is a preventive check

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 18 th centuries document millions of people perishing.

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).

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 = 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.

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.

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.

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.

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.

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.

Future Population Growth Many agencies suggest most (if not all) countries’ populations will stop growing at some time during the 21 st 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.

Demographic Transition

Population Pyramids related to the Demographic Transition Model Stage 1 Stage 2Stage 3Stage 4 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 IMPLICATIONS 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