8.1 Human populationsIB Environmental Systems and Societies HL: Subtopic test

1. 1
   Country A has a population of 96 million. Its age structure is: 0-14 years, 30 million; 15-64 years, 60 million; 65 years and over, 6 million. Its total fertility rate (TFR) fell to about 2.1 ten years ago. Even so, its population is still growing by about 1% a year, mainly through natural increase.

   (a)

   A TFR of about 2.1 is described as the replacement level. What does it mean?

   [1 mark]

   • AWomen have, on average, enough children to replace themselves and a partner in the long run
   • BEach woman has exactly 2.1 children every year
   • CThe death rate equals the birth rate immediately
   • DThe population doubles every 2.1 decades

   (b)

   What is the dependency ratio of Country A?

   [1 mark]

   • A10
   • B36
   • C50
   • D60

   (c)

   Explain why the population of Country A is still growing even though its TFR has fallen to the replacement level.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Niger and Germany are at different stages of the demographic transition. In Niger the TFR is above 6, about half of the population is under 15, and the birth rate is far higher than the death rate. Germany has a TFR of about 1.5 and a median age of about 45; deaths have exceeded births for many years, and its population has been held roughly steady by immigration.

   (a)

   Which stage of the demographic transition model best describes Niger?

   [1 mark]

   • AStage 1
   • BStage 2
   • CStage 3
   • DStage 4

   (b)

   Which description is most likely to fit the age-sex pyramid of Niger?

   [1 mark]

   • ANarrow base, wide middle and wide top
   • BStraight sides
   • CVery wide base narrowing rapidly towards the top
   • DWide at the top and narrow in the middle

   (c)

   Using Niger and Germany, explain why the two countries have different patterns of population structure and growth.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Lake Chad lies on the borders of Chad, Niger, Nigeria and Cameroon. Since the 1960s its surface area has shrunk dramatically because of reduced rainfall, repeated droughts and the withdrawal of water for irrigation. Millions of people around the lake depend on it for fishing, farming and herding. Many fishing and farming families have left the shores in search of work, moving to towns and to camps for displaced people elsewhere in the region.

   (a)

   Explain how climate-related changes around Lake Chad can cause environmental migration.

   [3 marks]

   (b)

   Discuss the consequences of environmental migration from the Lake Chad region for the areas that receive migrants.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   The world population rose from about 3 billion in 1960 to 8 billion in late 2022. United Nations projections suggest that it will peak at around 10 billion in the 2080s, although the projections assume that fertility will keep falling in sub-Saharan Africa. A 2023 assessment of the planetary boundaries model concluded that six of the nine boundaries, including climate change, biosphere integrity and land-system change, had been transgressed. The Global Footprint Network estimates that humanity uses resources at a rate equivalent to about 1.7 Earths, but resource use per person is many times higher in high-income countries than in low-income ones.

   (a)

   Evaluate the use of population models to predict the future global human population.

   [6 marks]

   (b)

   Discuss the extent to which rapid human population growth has increased stress on the Earth's systems.

   [6 marks]

   Total for question 4: 12 marks

End of questions