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IB ESS SL2.2 Energy and biomass in ecosystemsQuestion Bank

2.2 Energy and biomass in ecosystems

Question 1

Question 1(b)

(a)

Describe how the biomass of a field of crops might be measured.

[ 2 ]

Question 1(c)

(b)

Identify two reasons why a human vegetarian diet is considered to be more energy efficient than a diet containing meat.

[ 2 ]

Question 1

[Maximum number: 5]

The concentration of DDT at different trophic levels of the food chain.

Figure 1: Levels of concentration of DDT in food chain

Figure 1: Levels of concentration of DDT in food chain

Question 1(a)

(a)

State the main source of energy for the food chain in Figure 1.

[ 1 ]

Question 1(b)

(b)

State the trophic level labelled X in Figure 1.

[ 1 ]

Question 1(c)

(c)

Identify one use of DDT that has led to its presence in the environment.

[ 1 ]

Question 1(d)

(d)

With reference to the concepts of bioaccumulation and biomagnification, outline how the concentration of DDT has changed along the food chain. be marked.

[ 2 ]

Question 1

Question 1(b)

(a)
Figure 1(d): Climate graph for Roseau, Dominica

Figure 1(d): Climate graph for Roseau, Dominica

With reference to Figure 1(d), explain how the environmental conditions on Dominica result in high gross primary productivity.

[ 2 ]

Question 1

[Maximum number: 1]
Figure 2(a): Fact file on London

Figure 2(a): Fact file on London

Figure 9: Annual mean oxides of nitrogen ( \(\mathrm{NO

Figure 9: Annual mean oxides of nitrogen ( \(\mathrm{NO

Question 1(b)

(a)

Outline one factor which limits the primary productivity of an ecosystem in London.

[ 1 ]

Question 1

Question 1(a)

Question 1(a)(ii)

(a)
(i)

State how you could determine gross secondary productivity of the zebra.

[ 1 ]

Question 1(a)(iii)

(ii)

Explain how the second law of thermodynamics applies to this food chain.

Figure 1(b): Biting flies in the savanna

Figure 1(b): Biting flies in the savanna

Figure 1(b): Biting flies in the savanna

Figure 1(b): Biting flies in the savanna

Biting flies bite and drink the blood of zebras. They commonly carry diseases that can be fatal to zebras.

[ 2 ]

Question 1

Question 1(d)

(a)

Evaluate the possible use of grass carp in controlling the growth of water hyacinth in Inle Lake.

Floating gardens started in the 1960s; since then, lake area has decreased by one third.
Deforestation of surrounding hills increases sediment and nutrients in the lake.
Fertilizers and pesticides from floating gardens enter lake waters; increased nitrogen and phosphate lead to eutrophication and hypoxic water.
Water hyacinth is a fast-growing non-native floating plant; grass carp is non-native and feeds on water hyacinth.
A nearby coal mine and power plant discharge toxic waste into the lake; in drought years drinking water has to be brought in because the lake is too polluted.
The WWF lists the biodiversity of Inle Lake as vulnerable.

[ 4 ]

Question 1

Question 1(g)

(a)

With reference to Figures 4(b) and 9(b):

[ 1 ]

Question 1(g)(i)

(i)

Suggest a reason why a condor is likely to be poisoned even if a small proportion of the carcasses it consumes contain lead.

Figure 4(b): Probability of lead exposure for condors by diet

Figure 4(b): Probability of lead exposure for condors by diet

Figure 9(b): Lead and non-lead bullets after impact

Figure 9(b): Lead and non-lead bullets after impact

[ 1 ]

Question 1

Question 1(b)

Question 1(b)(i)

(a)
(i)

Explain why albatross chicks may starve if they eat plastic.

Figure 4(b): Dead albatross chick with plastic garbage in stomach

Figure 4(b): Dead albatross chick with plastic garbage in stomach

Figure 3/4: larger plastic pieces are taken in by fish, sea birds and animals, which may die of starvation.
One study estimates around 1 million sea birds, including albatrosses, and 100000 animals are killed by ingestion of plastic or entanglement in plastic fishing nets.
About half of all albatross species are endangered or critically endangered on the Red List.

[ 1 ]

Question 1(b)(ii)

(ii)

Explain why organisms at the top of the food web in the GPGP are likely to accumulate high concentrations of POPs (persistent organic pollutants).

Figure 3: the Great Pacific Garbage Patch is floating garbage in the North Pacific gyre; other ocean gyres also have garbage patches.
Estimates vary, with some estimating 3.5 million tonnes of plastic.
Garbage, mostly plastics from Pacific-bordering countries, floats to the GPGP in ocean currents and is trapped in the gyre.
Plastic pieces vary in size, may float at or just below the surface, and denser pieces may sink to the ocean floor.
Plastic is mostly non-biodegradable and breaks into smaller pieces; some small pieces absorb POPs as chemical sponges.

Figure 3/4: larger plastic pieces are taken in by fish, sea birds and animals, which may die of starvation.
One study estimates around 1 million sea birds, including albatrosses, and 100000 animals are killed by ingestion of plastic or entanglement in plastic fishing nets.
About half of all albatross species are endangered or critically endangered on the Red List.

[ 2 ]

Question 1(d)

Question 1(d)(i)

(b)
(i)

State the two material inputs of photosynthesis.

[ 1 ]

Question 1

Question 1(e)

(a)

Bithynia feeds on plant material in the wetland ecosystem.

[ 1 ]

Question 1(e)(i)

(i)

State its trophic level in the ecosystem.

[ 1 ]

Question 1

Question 1(a)

(a)
Figure 4(a): Average net primary productivity of ecosystems

Figure 4(a): Average net primary productivity of ecosystems

Figure 4(b): Mudflats along the St Lawrence River estuary at low tide

Figure 4(b): Mudflats along the St Lawrence River estuary at low tide

Figure 2(a): Fact file on the St Lawrence River estuary and Gulf of St Lawrence
The St Lawrence River estuary and Gulf of St Lawrence are recognized as a Large Ocean Management Area by the Canadian government.
The area is an important shipping route, highly productive, provides habitat for birds, whales and crabs, and provides nursery grounds for commercial fish species.
Management is challenging because stakeholder interests may conflict or be environmentally damaging.

Using Figure 4(a), identify an ecosystem that has an average net primary productivity above 30000 kJ m−2a−130000 \mathrm{~kJ} \mathrm{~m}^{-2} \mathrm{a}^{-1}.

[ 1 ]

Question 1(c)

(b)

Estuaries are one of the most productive ecosystems in the world, but only account for 3 % of global productivity.

State one reason why this occurs.

[ 1 ]

Question 1(d)

(c)

Outline why estuaries are highly productive ecosystems.

[ 3 ]
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