| Date | May 2021 | Marks available | 1 | Reference code | 21M.1.SL.TZ1.21 |
| Level | Standard level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 21 | Adapted from | N/A |
Question
The diagram shows the energy flow between five “sinks” in a terrestrial ecosystem.
In a typical terrestrial ecosystem, which trophic level would have the highest biomass?
A. Autotrophs
B. Primary consumers
C. Secondary consumers
D. Detritus feeders
Markscheme
A
Examiners report
Syllabus sections
- 16N.1.SL.TZ0.18: What restricts the length of a food chain? A. Energy losses between the trophic levelsB. A...
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21M.2.SL.TZ2.4d.i:
Deduce whether jellyfish or crustacea are a richer source of carbon in a food chain.
- 17M.2.HL.TZ2.4a.ii: Using the food web, identify a saprotroph.
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20N.2.HL.TZ0.4a:
Distinguish between the transfers of energy and inorganic nutrients in ecosystems.
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19M.1.HL.TZ1.14:
The diagram shows the food web for an aquatic ecosystem in which letters R–Z represent individual species.
[Source: © International Baccalaureate Organization 2019]
Which organism is a tertiary consumer?
A. Organism T
B. Organism U
C. Organism W
D. Organism Y
- 17M.2.HL.TZ2.4c: Outline the energy flow through this food web.
- 17N.2.SL.TZ0.04b: Outline why the number of trophic levels is limited in a food chain.
- 22M.2.SL.TZ1.1g: Outline the relationship between ambient daily temperature and food intake in March.
- 18N.1.SL.TZ0.17: The diagram shows interactions between food chains in an ecosystem in the African...
- 18M.1.HL.TZ2.22: Which processes occur in an ecosystem? I. Biomass increases in each successive trophic...
- 16N.2.SL.TZ0.1f: Identify an example of competition between organisms in this food web.
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19M.1.SL.TZ1.18:
The diagram shows the food web for an aquatic ecosystem in which letters R–Z represent individual species.
[Source: © International Baccalaureate Organization 2019]
Which organism is a tertiary consumer?
A. Organism T
B. Organism U
C. Organism W
D. Organism Y
- 17M.1.SL.TZ2.17: What is lost between trophic levels in ecosystems and cannot be recycled? A. Heat B....
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21N.2.SL.TZ0.3b.i:
The image shows an example of a soil food web.
[Source: Anon., n.d. The Soil Food Web. [image online] Available at: https://www.nrcs.usda.gov/wps/portal/nrcs/
photogallery/soils/health/biology/gallery/?cid=1788&position=Promo [Accessed 11 March 2020].]Draw a food chain from this food web, showing at least three organisms.
- 17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive...
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16N.2.SL.TZ0.1e:
The trout, Oncorhynchus mykiss, that live in West Brush Creek and Cement Creek also feed on the mayflies. Fishermen come to Colorado to catch and eat trout. Draw a diagram of part of a food web for the creeks in Colorado, including mayflies, humans, trout and bats.
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16N.2.SL.TZ0.7c:
Draw a labelled diagram of a pyramid of energy.
- 17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
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19N.2.HL.TZ0.8c:
Explain the movement of energy and inorganic nutrients in an ecosystem.
- 22M.2.SL.TZ1.1h: Suggest, with a reason, how the activity of the sloth varies with ambient temperature.
- 22M.1.SL.TZ2.18: The diagram shows part of a food chain. The left box represents producers and the right box...
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22M.2.SL.TZ2.7a:
Outline energy flow through a community in a natural ecosystem.
- 21N.1.SL.TZ0.18: In a woodland ecosystem, each tree provides food for numerous aphids which feed on the sap of...
- 22M.1.SL.TZ1.18: The table contains information about the diet of some animals. Which pyramid of energy...
- 17M.3.HL.TZ1.13c: Distinguish between mutualism and parasitism, providing another example of mutualism and...
- 20N.1.HL.TZ0.16: Plankton are major producers in marine ecosystems. Only a small proportion of the energy...
- 22M.2.SL.TZ1.1f: The mean daily food intake fluctuated from day to day. State the month that contains the day...
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21N.2.HL.TZ0.1b:
Compare and contrast the effects of temperature on the biomass of autotrophs and heterotrophs with added nutrients.
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21N.2.HL.TZ0.1d:
Suggest reasons for the decreases in biomass of autotrophs as temperature rises, despite the increases in photosynthesis.
- 19M.2.HL.TZ2.8a: Outline energy flow through a food chain.
- 18M.1.SL.TZ1.17: Animals in the highest trophic level of a food chain will often be the largest in body size...
- 17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
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20N.2.HL.TZ0.8a:
Outline the criteria that should be used to assess whether a group of organisms is a species.
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21M.1.SL.TZ2.18:
The diagram shows the flow of energy through an ecosystem in
[Source: “Energy flow: Figure 3,” (https://cnx.org/contents/24nI-KJ8@24.18:fbNheNoN@8/Energy-Flow) by OpenStax College, Biology CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).]
What percentage of the energy passed from primary producers to primary consumers is lost to cellular respiration by tertiary consumers?
A. 0.001%
B. 0.08%
C. 0.2%
D. 0.4%
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21M.2.SL.TZ2.4c:
Explain how energy enters, flows through and is lost from marine food chains.
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21M.2.SL.TZ2.4d.ii:
Suggest with a reason whether having a large body mass is an advantage or disadvantage for jellyfish.
- 18M.2.HL.TZ2.6c: Describe the reasons for the shape of a pyramid of energy.
- 17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
- 18M.2.SL.TZ2.3c: Explain how energy and nutrients are transferred in ecosystems.
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16N.2.SL.TZ0.7a:
Explain the processes by which energy enters and flows through ecosystems.
- 19N.2.SL.TZ0.5c: Explain the movement of energy and inorganic nutrients in an ecosystem.
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16N.2.HL.TZ0.8c:
Describe how energy flows through and is used by organisms in ecosystems.
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19M.2.SL.TZ2.3a.i:
State two causes of the decrease of biomass along food chains in terrestrial ecosystems.
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17M.2.SL.TZ1.2d:
Explain the role of decomposers in an ecosystem.
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21N.2.SL.TZ0.3b.ii:
Explain the reasons for food chains rarely containing more than four or five trophic levels.
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19M.1.SL.TZ2.18:
The Silver Springs feed into the Silver River in Florida. The diagram shows a pyramid of energy for the Silver Springs ecosystem. The units are kJ m–2 y–1.
[Source: © International Baccalaureate Organization 2019]
What do level I and level III represent in the pyramid of energy?
