2 Terms to Know BR(birth rate) DR(death rate) # of births/1000 in populationDR(death rate)# of deaths/1000 in populationRNI(rate of natural increase)(BR-DR)÷10IMR(infant mortality rate)# of infant deaths/1000 live birthsTFR(total fertility rate)avg. # of children born to a woman of childbearing age given her country’s BR and DRExponential Growth Website
3 Demographic Transition Model It is based on an interpretation begun in 1929 by the American demographer Warren Thompson, of the observed changes, or transitions, in birth and death rates in industrialized societies over the past two hundred years or so.
4 Demographic Transition Model It is an idealized, composite picture of population change in these countries. The model is a generalization that applies to these countries as a group and may not accurately describe all individual cases. Whether or not it applies to less developed societies today remains to be seen.
6 Stage OneBoth high birth rates and death rates fluctuate in the first stage of the population model giving a small populationlittle access to birth controlmany children die in infancy (high infant mortality) so parents tend to have more children to compensate in the hopes that more will livechildren are needed to work on the land to grow food for the familychildren are regarded as a sign of virility in some culturesreligious beliefs (e.g. Roman Catholics and Hindus) encourage large familieshigh death rates, especially among children because of disease, famine, poor diet, poor hygiene, little medical science.
7 Stage TwoBirth rates remain high, but death rates fall rapidly causing high population growth.improvements in medical care - hospitals, medicines, etc.improvements in sanitation and water supplyquality and quantity of food produced risestransport and communications improve the movements of food and medical suppliesdecrease in infant mortality.
8 Stage ThreeBirth rates now fall rapidly while death rates continue to fall. The total population begins to peak and the population increase slows to a constant.increased access to contraceptionlower infant mortality rate means there is less need to have a bigger familyindustrialization and mechanization means fewer laborers are requiredthe desire for material possessions takes over the desire for large families as wealth increasesequality for women means that they are able to follow a career path rather than feeling obligated to have a family
9 Stage FourBoth birth rates and death rates remain low, fluctuating with 'baby booms' and epidemics of illnesses and disease. This results in a steady population.most preventable deaths are avoided
10 Stage Five???Total population is declining because birth rates have dropped below death rates.Not originally part of the model, but many post-industrial countries find themselves in this position.
11 Population PyramidsUseful tool for understanding the structure and composition of populations because they graphically portray many aspects of a country, such as sex ratios and age structuresCan give insights into trends in populations over time by their portrayal of the relative number of people in a cohort (example “baby boom”)
19 Stationary PyramidShows roughly equal numbers of people in all age categories, with a tapering towards the older age categoriesCountries such as Iceland, show stationary age categories because of relatively low, constant birth rates and high quality of life