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# Demographic transition

Demographic transition is a model that tracks changes in a country's population. It predicts population stabilization as countries transition from high birth and death rates to low ones. This typically happens in industrialized nations. The model has five stages, each representing different population trends. The future of population growth, however, remains uncertain. Created by Sydney Brown.

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• It wasn't obvious to me what the pyramid charts were graphing. It would be nice if you labeled the axises.
• Agreed. Based on the info provided by this website (http://pages.uwc.edu/keith.montgomery/Demotrans/demtran.htm) I think that the y-axis represents the age variable (e.g. 0-10yr, 10-20yr, etc) and that the x-axis represents the # of people. The dashed midline is where the zero mark. The violet and red lines are for each sex (i.e. male and female).
• where is the canada among the stages?
• If you look at the population pyramid of Canada on Google Image, you'll see that it's clearly at stage 4.
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• Can someone explain the Malthusian Theory and if it predicts a decrease or stabilization in population?
• At she says "high stationary population pyramid" but the "Overview of demographics" video has a correction that says it's expansive population pyramid, not high stationary. But the correction doesn't make sense to me because birth and death rates are both high so the overall population is neither increasing nor decreasing, so shouldn't it be stationary?
• Ya...so fertility generally has a larger effect on population growth than death rate because in this day and age, death rates are generally decreasing (unless we have a huge death rate due to an epidemic or war). Yes, the birth and death rate are high, but the birth is often higher than the relatively high death, so "expansive" is a better label.

The way I reason it, is that these graphs are snap shots, where as population growth is dynamic. In a country where the birth rate is high due to kids being useful to the economy, and where the death rate is high due to low health care, the birth rate will decrease if there is a social change and kids are not used as workers whereas death rates will decrease if sanitation and care for the elderly improves. The latter occurs more readily, so the death rate will start to slowly decrease even though the birth rate is high, leading to stage 2! In other words, I'd call stage one early expansive :)

• At Stage 4 of the model, if the life expectancy is said to be longer, than shouldn't you have drawn the graph taller?
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• This seems to state that population, after a long decline, eventually stabilizes, but it gives no reason for the end of population decline. Rather, it seems to state that in the future, after some period of decline, the population will magically? "balance" and remain stable. But everything else I read says that once total reproduction rate, followed by population population, begin to fall we recognize no cause for it to stop falling. All the way to zero. Comments?
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• Which of the stages shows natural increase, thanks.
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• Not a question, just a statement: when Sydney says that some governments, like China, are introducing government policies to encourage smaller families - however, coincidentally on this day in 2015 (10 June), China announced that it was removing it's one-child policy and returning to the 2-child policy it had before 1980 since their culture of favoring boys over girls has resulted in a much larger male population over female population. This is also compounded by the fact that culturally people take care of their grandparents and parents as they age, so a couple would have 4 parents between them to care for since neither person in the couple has a sibling (due to the 1-child policy their parents were under).
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• After 23 years, about half of Zed's original population will no longer the majority. Probably less, because that assumes the immigrants will not have children when in real life they usually have more births per woman than the natives of the country. It also assumes that the population was 100% homogenous, which probably isn't the case.
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• So... in stage five nobody knows what will happen. I have a theory. The population will age so that there's a lot of elderly people and they need younger people to take care of them. The younger people will have more children after they realize that if they don't, they might end up being old with no one to take care of them. Does anyone else have any theories?
(1 vote)