Practice 2.5 Zonation, succession and change in ecosystems with authentic IB Environmental systems and societies (ESS) exam questions for both SL and HL students. This question bank mirrors Paper 1, 2 structure, covering key topics like ecosystems, human impact, and sustainability. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
Paper
Level
Question 1
SL & HLPaper 2
1.[4]
Explain how you would measure the impact of pollution on a freshwater ecosystem.
Question 2
SL & HLPaper 2
Explain how abiotic factors can be measured in an ecosystem investigation.
1.[4]
Choose two factors and describe the measurement method for each.
Question 3
SL & HLPaper 2
1.[4]
Describe two methods for estimating population size in an ecosystem.
Question 4
SL & HLPaper 2
1.[3]
Explain the importance of replication in ecological field studies.
Question 5
SL & HLPaper 2
in a forest ecosystem study
1.[3]
Explain how a clinometer can be used to measure tree height.
Question 6
SLPaper 1
Figure 1: Plant species present on two volcano slopes that erupted in the 1880s. Measurements taken in 1930, 1975 and 2015.
| Volcano | Latitude | Eruption date | Type of surface | Number of species (plants) recorded in three separate years |
|---|---|---|---|---|
| 1930 | ||||
| Krakatau, Indonesia | 6 degrees south | 1883 | Ash and lava | 24 |
| Tarawera, New Zealand | 38 degrees south | 1886 | Lava | 2 |
1.[4]
Explain two reasons behind the differences in the number of plant species found.
2.[3]
Explain a method of measuring plant species abundance in volcanic areas.
Question 7
SL & HLPaper 2
1.[4]
Describe two methods for measuring soil characteristics in an ecosystem study.
Question 8
SL & HLPaper 2
1.[3]
Explain the importance of random sampling in ecological investigations.
Question 9
SLPaper 1
Figure 1: Fact file on North American beavers
- Typically, one family per square kilometer of river habitat.
- Live in family groups consisting of two adults and up to three kits, born annually between April and June.
- Experience high mortality rates due to harsh weather, limited suitable habitats, and predation.
- North American beaver population:
- Estimated at 250 million before the fur trade.
- Currently around 9 million.
- Primarily feed on tree bark.
- Build lodges using wood and mud, which serve as:
- Safe spaces for eating, sleeping, and raising young.
- Winter shelters where they remain during the colder months.
- Defended structures to keep other beavers out.
- Beavers are being reintroduced in Europe to aid in wetland restoration.
Source: adapted from www.sbaa.ca, www.ecology.info, www.tobyhemenway.com and http://acs7.cortland.edu
Figure 2: Algonquin wolf pack territories and protected areas
1.[1]
With reference to Figure 1, outline one reason why there are more beaver remains in wolf faeces during summer.
2.[2]
The number of wolves in Algonquin Provincial Park is estimated to be between 250 and 1000. Outline two reasons why it is so difficult to estimate the number of wolves accurately.
3.[3]
With reference to Figure 2, explain the threats to the future existence of a small and sustainable population of wolves as a result of their protection in limited area.
Question 10
SLPaper 1
Figure 1: The Nadezhda smelting plant in Norilsk opened in 1979
The plant may be a possible source of the water discolouration.
Figure 2: Daldykan River in Norilsk
1.[3]
Describe a practical strategy using a biotic index to provide evidence that the Daldykan River (Figures 1 and 2) is damaged by effluent from the metal processing plant.
2.[1]
When measuring levels of pollution, state one advantage of using a biotic index compared to measuring the pollutants directly.
Advantage:
3.[1]
When measuring levels of pollution, state one disadvantage of using a biotic index compared to measuring the pollutants directly.
Disadvantage: