IB ESS SL Topic 2 Ecology Question Bank

Practise IB ESS SL Topic 2 Ecology through questions on species, populations, communities and ecosystem relationships.

Covered syllabus points

2.1 Individuals, populations, communities, and ecosystems 2.2 Energy and biomass in ecosystems 2.3 Biogeochemical cycles 2.4 Climate and biomes 2.5 Zonation, succession and change

[Maximum number: 5]

Figure:Example of a lake ecosystem

Figure: Example of a lake ecosystem below shows an example of a lake ecosystem.

Rooting flowering plants: producers

(a)

State the source of energy for this ecosystem.
(a) (i) State the source of energy for this ecosystem.

[ 1 ]

(b)

Identify one way in which energy may leave this ecosystem.

Birds: secondary and tertiary consumer eg kingfisher

Floating plants: producers eg lilies, water fern

Frog: secondary consumer

[ 1 ]

(c)

Draw a food chain from the ecosystem in Figure: Example of a lake ecosystem consisting of four trophic levels.

[ 1 ]

(d)

Identify two possible effects of removing trout on this ecosystem.

[ 2 ]

[Maximum number: 11]

(a)

Identify four characteristic features of the tropical rainforest biome.

[ 4 ]

(b)

Explain how a community of decomposers contributes to the stability of the whole ecosystem.

[ 7 ]

Explain how a community of decomposers contributes to the stability of the whole ecosystem
a. Decomposers will feed on dead organic matter/detritus (like dead leaves, wood, carcasses, feces)...;
b. ... reducing their accumulation / cleaning up Earth;
c. They will break down organic matter into inorganic matter…;
d. ...enhancing soil fertility / increasing nutrient availability;
e. The inorganic minerals (nitrates, phosphates, metals) will then feed plant communities / will be absorbed by plant roots...;
f. ...supporting high vegetation/plant abundance;
g. ...and may support high habitat/niche diversity;
h. Decomposers are responsible for nutrient cycling / e.g. nitrogen cycling (nitrogen fixation/ammonification/nitrification/denitrification/phosphorus cycling/carbon cycle;
i. ...high flow of matter may support complex food webs;
j. Decomposers are the basis of a detritus-based food web / important part of ecosystem flow of energy / may be eaten/pass biomass on to carnivore community...; k. ...supporting/stabilizing carnivore abundance;
I. As decomposer numbers decrease due to predation, so do carnivores;
m. ... thereby contribute to regulation of the carnivore community / which is an example of negative feedback (leading to stability); n. Decomposer will release organic matter through their own death/defecation...; o. ... which would provide food for other decomposers; p. Decomposers participate in humus formation...; q. ...increasing water holding capacity of soil (and soil fertility = MPd); r. Decomposers may compete with one another regulating their populations (another example of negative feedback = MPm); s. Decomposers, like earthworms, loosen soil / disperse nutrients / create space for air and water circulation...; t. ...helping root growth / improving soil structure; u. Fragmentation: larger invertebrates initially fragment larger chunks of organic matter (then bacteria and fungi complete decomposition into nutrients = MPc);
v. After a disturbance, decomposers will increase their metabolic/respiration rate/feeding on detritus...;
w. ...contributing to a faster return to original state (resilience entailing stability);

[Maximum number: 3]

(a)

Figures:Fact file on Hokkaido and Climate graph for Sapporo, Hokkaido

Using the climate graph for Sapporo, state the annual temperature range for Sapporo.

[ 1 ]

$27^{\circ} \mathrm{C} /$ from -4 to $(+) 23^{\circ} \mathrm{C}$ ;

Marking guidance:

Accept use of dash to indicate 'to'. Units are not required for credit.

(b)

Figure:World map showing location of Japan

Figures:Fact file on Hokkaido and Climate graph for Sapporo, Hokkaido

Figure:Elevation map of Hokkaido

Using Figures: World map showing location of Japan, Climate graph for Sapporo, Hokkaido and Elevation map of Hokkaido, identify one terrestrial biome found on Hokkaido.

[ 1 ]

(c)

Figure:Hokkaido's national parks and airports

Using Figures: Elevation map of Hokkaido and Hokkaido's national parks and airports, outline one relationship between the location of Hokkaido's national parks and their elevation.

[ 1 ]

a. national parks are mainly found in areas above $500 \mathrm{~m} / 1000 \mathrm{~m}$ in elevation / found mainly in the areas of highest/high elevations;
b. (there is no relationship, as) the national parks are found at all elevations (i.e. Kushiro Marshlands);

Note: Must give a reason if they say there is no relationship.

[Maximum number: 1]

Figure:Salinity variation in the Large Ocean Management Area

Figure:Water-surface temperature variation across the LOMA

Figure:temperature scale

Suggest one reason for the zonation seen in Figure: Water-surface temperature variation across the LOMA.

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Covered syllabus points

Topic 2: Ecology question 1

Question (a)

Question (b)

Question (c)

Question (d)

Topic 2: Ecology question 2

Question (a)

Question (b)

Topic 2: Ecology question 3

Question (a)

Question (b)

Question (c)

Topic 2: Ecology question 4