| Date | May 2019 | Marks available | 2 | Reference code | 19M.1.SL.TZ0.8 |
| Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 0 |
| Command term | Describe | Question number | 8 | Adapted from | N/A |
Question
Figure 5: Ecosystem goods and services in coastal marine habitats
With reference to Figure 5, describe how loss of a coral reef ecosystem could impact a neighbouring seagrass community.
Markscheme
would reduce protection from waves/currents/storms / increase in damage to seagrass community from waves/currents/storms;
could reduce food source for some seagrass species;
could reduce spawning areas/nursery grounds for some seagrass species;
could increase/decrease predation pressure on seagrass species from other marine species;
without coral to filter the water, the water clarity would decline adversely affecting seagrass / an increase in water turbidity, making it difficult for light fixation/photosynthesis by seagrass;
loss of coral reefs will reduce tourism to the area thereby reducing funds available for protection of seagrass ecosystems;
Do not accept only “there is loss of biodiversity”.
Do not accept only “increase/decrease in water turbidity/clarity” without impact on seagrass.
[2 max]
Examiners report
Few candidates achieved 2 marks, most responses only considered one way in which a loss of coral reef would impact a seagrass community. A common error was to discuss the role of coral reef but not what would happen to seagrass in the absence of coral reefs. Some candidates incorrectly stated that the organisms from the coral reef would simply relocate to the seagrass ecosystem.
Syllabus sections
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14N.2.SL.TZ0.3a:
Distinguish between a pyramid of numbers and a pyramid of productivity.
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17N.2.SL.TZ0.7a:
Outline how soil can be viewed as an ecosystem.
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17N.2.SL.TZ0.4a:
Describe the role of primary producers in ecosystems.
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19N.1.SL.TZ0.2e:
Suggest why the St Lawrence River beluga whale population has not recovered despite being given protected status in 1983.
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14M.1.SL.TZ0.1a.i:
State the source of energy for this ecosystem.
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16M.1.SL.TZ0.1e.i:
State its trophic level in the ecosystem.
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19M.1.SL.TZ0.7:
Explain two ways in which mangroves improve the water quality for primary producers within marine ecosystems.
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18N.1.SL.TZ0.3a:
With reference to Figure 6, draw a food chain that includes four trophic levels.
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18M.2.SL.TZ0.5b:
Suggest the procedures needed to collect data for the construction of a pyramid of numbers for the following food chain:
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17N.1.SL.TZ0.7:
To what extent might Iceland be viewed as a role model for sustainability by other countries?
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19N.1.SL.TZ0.2d:
With reference to Figure 8, explain why the beluga whale is more at risk from toxic pollutants, such as heavy metals and persistent organic pollutants (POPs), than most other organisms in its food web.
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19N.1.SL.TZ0.3b:
With reference to Figure 9(a), outline how the round goby both positively and negatively affects the St Lawrence River ecosystem.
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16M.2.SL.TZ0.1c.iii:
Identify four factors that would affect the primary productivity of forest plantations in the Copperbelt Province.
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18N.1.SL.TZ0.10a:
With reference to Figure 7(a), outline one reason why there are more beaver remains in wolf faeces during summer.
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18N.1.SL.TZ0.3b:
Identify two ways that human activity in Algonquin Provincial Park may affect the food web.
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17N.1.SL.TZ0.5c:
Identify two reasons why the future size of the Atlantic puffin population is difficult to predict.
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18M.2.SL.TZ0.4b:
Explain how a community of trees in a woodland may be considered a system.
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19N.1.SL.TZ0.2a:
Using Figure 6(c), identify a food chain in the St Lawrence River ecosystem that has five trophic levels.
- 17N.1.SL.TZ0.5a.ii: Identify one argument against humans hunting puffins.
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14M.1.SL.TZ0.4d:
Explain how the use of non-biodegradable pesticides on farmland may affect the human food chain.
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19M.2.SL.TZ0.1d:
Outline two ways in which the food web is likely to change as a result of succession.
- 18N.2.SL.TZ0.4c: Using examples, discuss whether habitat conservation is more successful than a species-based...
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17M.2.SL.TZ0.1d:
With reference to the concepts of bioaccumulation and biomagnification, outline how the concentration of DDT has changed along the food chain.
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16M.2.SL.TZ0.1d.i:
With reference to Figure 7, state the most common ecosystem in Zambia.
- 18N.1.SL.TZ0.1: Identify one ecosystem in Algonquin Provincial Park.
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17M.2.SL.TZ0.1b:
State the trophic level labelled X in Figure 1.
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19N.1.SL.TZ0.1d:
Outline why estuaries are highly productive ecosystems.
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17N.1.SL.TZ0.5b:
With reference to Figure 8(c) state the impact that an increase in the mackerel population might have on the Atlantic puffin population.
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14N.1.SL.TZ0.2b:
Elephants eat a variety of vegetation: grasses, shrubs, leaves and small tree seedlings. Describe the impact on a grassland ecosystem of the main large herbivore being removed.
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16N.2.SL.TZ0.4a:
Outline why top carnivores are vulnerable to non-biodegradable toxins.
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14N.2.SL.TZ0.4b:
Explain the transfer of energy through an ecosystem. Support your explanation with a labelled diagram.
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16N.1.SL.TZ0.4c:
Describe how the second law of thermodynamics operates in relation to the transfer of energy within the Silver Springs ecosystem.
- 18M.2.SL.TZ0.3a: Identify one producer in the system illustrated in Figure 3.
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16N.1.SL.TZ0.4d:
Distinguish between a pyramid of numbers and a pyramid of productivity.
