Quelpr
4 marksEnergy Flow and Nutrient Cycling

CAPE Biology Unit 2 · May/June 2025 · Paper 2 · Question 1(b)(i)

In a mangrove ecosystem, algae harvest about 170 000 kJ m⁻² yr⁻¹ of sunlight energy. Crabs consume algae, harvesting about 12% of the energy obtained by the algae. Marine birds consume crabs, harvesting 10% of the energy obtained by the crabs.

Given the information above, construct a pyramid of energy with corresponding values for the mangrove ecosystem.

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 1(a)(i)Name the THREE stages of the light-independent reactions that occur in the Calvin cycle, labelled X, Y and Z in Figure 1.[3 marks]
  2. 1(a)(ii)State the functions of reduced NADP+ and ATP in the light-independent reactions.[2 marks]
  3. 1(a)(iii)Outline a suitable procedure for conducting the investigation.[5 marks]
  4. 1(b)(ii)Determine the productivity of the producer in the mangrove ecosystem if 1 000 000 kJ m⁻² yr⁻¹ of energy is provided by sunlight to the mangrove.[2 marks]
  5. 1(b)(iii)State TWO reasons why all the energy available from sunlight is not used by the algae.[2 marks]
  6. 1(c)(i)Define EACH of the following components of biodiversity: Species diversity, Genetic diversity, Ecosystem diversity.[3 marks]
  7. 1(c)(ii)Explain the impact of climate change on EACH of the following components of biodiversity. You MUST present your response in complete paragraphs: Species…[9 marks]

More practice: the rest of this paper · more Energy Flow and Nutrient Cycling questions · all CAPE Biology Unit 2 past papers