8.1 Human populationsIB Environmental Systems and Societies HL: Flashcards
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How is the dependency ratio calculated?
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- How is the dependency ratio calculated?
- (Number aged 0-14 + number aged 65 and over) ÷ number aged 15-64 × 100.
- Define population momentum.
- Continued population growth after TFR falls to replacement level, due to a large young cohort entering reproductive age.
- Define total fertility rate (TFR).
- The average number of children a woman would have in her lifetime at current age-specific birth rates.
- Name the inputs and outputs of a human population.
- Inputs: births, immigration. Outputs: deaths, emigration.
- How is natural increase calculated?
- Birth rate − death rate (migration excluded).
- State the rule of 70.
- Doubling time (years) ≈ 70 ÷ annual growth rate (%).
- Give an example of a country in stage 2 of the DTM and one feature.
- Niger: TFR above 6, a very young population and rapid growth.
- Give an example of a country in a late DTM stage and one feature.
- Germany: TFR about 1.5, older population, deaths exceed births.
- Give two environmental causes of migration.
- Drought, climate change or land degradation (also sea-level rise).
- Give an example of environmental migration.
- Lake Chad shrinkage pushing people to towns and displacement camps.
- How many planetary boundaries have been transgressed (2023 assessment)?
- Six of the nine.
- Why do projections of future population carry uncertainty?
- They rely on assumptions about fertility, mortality and migration that may change.
- Give one direct and one indirect population policy.
- Direct: one-child policy. Indirect: girls' education and family planning.
- What does an age-sex pyramid with a very wide base show?
- High fertility and a young, rapidly growing population.
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).