QCEVault

Functioning ecosystems and succession — Question 3

QCAA 2021, Paper 1 · 1 mark

Q3 · 2021 · Paper 1Unclassified1 mark

QUESTION 3

In ocean food webs, where phytoplankton is in the first trophic level, the second trophic level of zooplankton often has a higher biomass than the phytoplankton at any given time. Which explanation would account for this?

(A) The zooplankton are also able to photosynthesise.

(B) Different phytoplankton species are preying on each other.

(C) Carnivores in the third trophic level have increased their consumption of zooplankton.

(D) The phytoplankton multiply much faster than zooplankton, but their lifespan is shorter.

Question linkQCAA assessment resources

Related questions

  1. Q2 · 2025 QCAA · Paper 1 · 1 mark
    QUESTION 2 The diagram shows energy flow through an ecosystem in kJ m−2 year−1. Shaded boxes represent gross productivity. Respiration and heat 50 000 7800 Primary consumers Sunlight Producers 7 200 000 87 000 22 600 5060 Decomposers Calculate the percentage of solar energy available to primary consumers. (A) 0.1% (B) 0.2% (C) 0.4% (D) 0.5%
    Functioning ecosystems and succession
  2. Q7 · 2025 QCAA · Paper 1 · 1 mark
    QUESTION 7 Which process is involved in both carbon and water cycling? (A) respiration (B) evaporation (C) transpiration (D) precipitation
    Functioning ecosystems and succession
  3. Q20 · 2025 QCAA · Paper 1 · 1 mark
    QUESTION 20 The graph shows the relative impact of habitat destruction, overexploitation, pollution and other human activities on four taxonomic groups. Reptiles and amphibians Land mammals Birds Fish 0 10 20 30 40 50 60 70 80 90 100 Relative impact (%) Key Habitat destruction Overexploitation Pollution Other Which activity has the greatest impact on terrest…
    Functioning ecosystems and succession
  4. Q22 · 2025 QCAA · Paper 1 · 5 marks
    QUESTION 22  (5 marks) a) Compare the role of pioneer species in primary and secondary succession. [3 marks] Similarity:
    Difference:
    Significance:
    b) Describe two ways climax communities differ from pioneer communities. [2 marks]
    Functioning ecosystems and succession