The Demographic Transition Model (DTM) is a model that shows population change over time as countries progress through four to five stages of development. It suggests that as countries industrialize, death rates fall before birth rates, leading to population growth. Eventually, birth rates also fall. The DTM helps explain population changes in industrialized countries, but is less relevant for non-industrialized nations. Population pyramids can reveal a country's population structure and predict future changes based on birth and death rates of different age groups. They may indicate issues like an aging population or low life expectancy.

1. The Demographic Transition ModelAS Geography

2. Learning ObjectivesTo learn the concepts behind the DTMDraw, label and interpret pop’n pyramidsHow population pyramids can be used to predict pop’n changeHow various pop’n structures can cause issues for countries concerned

3. What is itThe DTM is a simple diagramIt is a model that shows pop’n change over timeIt is a simplified version of realityIt suggests all countries go through 4 – 5 stages of developmentIt can be used to predict population changes over time

5. StrengthsIt’s dynamic showing changes over timeIt describes effectively what happened in the UKMany industrialised countries went through similar stages in Europe and N. AmericaSome NIC’s (S. Korea, Singapore) Also seem to go through similar stages but faster than the UK didIt helps explain what happened and why in a particular sequence

6. WeaknessesNot very relevant to non industrialised countriesModel assumes stage 2 followed from industrialisation (For many this was not the case)The factors that caused falls in DR were often imported from EuropeAssumes stage 3 follows several decades after stage 2 and that DR fell as a consequence of changes brought about by changes in BROften the onset of stage 3 held back by attitudes to family size, birth control, status, religion

7. WeaknessesSome Govt’s sped up the difference between stage 2 and 3 by introducing one child policies (China)Original model only contained 4 stages now 5 to show where DR is exceeding BR (Ageing pop’n)DR risen rapidly due to diseases e.g. Africa and Aids – does not help predict this.

8. DTM and Population Pyramids

9. Population PyramidsThese are good for showing the structure of a country’s pop’n

10. Population Pyramids can show:The results of Birth minus deaths in a specific age groupThe effects of migrationThe effects of war, famine or diseaseAn indication of life expectancy

11. ActivityReview the following pyramids and see how well you can interpret themThink about:What type of country they are from, where they are in terms of the DTM and possible reasons for their shape

14. General Shapes

15. Age Structures and ProblemsAgeing populationYoung populationLow Life expectancy populationWhat problems can you foresee with these kind of populations?

16. Learning ObjectivesTo learn the concepts behind the DTM

17. Draw, label and interpret pop’n pyramids

18. How population pyramids can be used to predict pop’n change

19. How various pop’n structures can cause issues for countries concerned