7/27/2019 pred-prey question.docx

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1. Snail kites are birds that feed on freshwater snails. Figure 1 shows the variation inpopulation numbers of both snails and snail kites in an ecosystem for the first eight-month period, January to August of the year…

(a) With reference to Fig 1, describe the variation in the population size of BOTHorganisms over the eight month period. (4 marks)

(b) Outline how predation may be of benefit to the prey population represented in Fig1. (4 marks)

(c) Explain how ONE density independent factor may impact the size of the snailpopulation. (4 marks)

(d) Assess TWO possible impacts on the ecosystem if the population of snails issignificantly reduced by draining the waterway. (8 marks)

(Total = 20 marks)

7/27/2019 pred-prey question.docx

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2. Figure one represents a pyramid of energy for a mango tree… 

(a) Account for the shape of the diagram. (2 marks)

(b) Draw a diagram showing the pyramid of numbers for the mango tree. (3 marks)

(c) Account for the difference in shape between the pyramid of energy and the pyramidof numbers drawn in (b) above. (5 marks)

(d) State FOUR limiting factors for an aquatic ecosystem. (4 marks)

(e) Four  TWO of those factors identified in (d) OUTLINE how they impact on thepopulation of organisms in an aquatic ecosystem. (6 marks)

(Total = 20 marks)