QUESTION 54 (5 marks)
Three relationships are observed: a tick feeds on a wallaby; a fungus supplies a plant with mineral nutrients while receiving sugars; a barnacle gains transport on a whale without a measurable effect on the whale.
a) Identify each interaction in the order given. [3 marks]
b) For one interaction, explain your classification in terms of benefits and costs to both organisms. [2 marks]
Practice marking scheme
Answer
a) Parasitism; mutualism; commensalism. b) For example, the fungus and plant both benefit: the fungus gains sugars and the plant gains nutrients.
Working
Parasitism benefits the tick and harms the wallaby. Mutualism benefits both the fungus and plant. Commensalism benefits the barnacle while the whale is unaffected under the stated conditions. A complete explanation identifies effects on both partners, rather than merely naming a resource.
Marking criteria
- Identifies parasitism. [1 mark]
- Identifies mutualism. [1 mark]
- Identifies commensalism. [1 mark]
- States the effect on one organism in a chosen interaction. [1 mark]
- States the corresponding effect on the other organism. [1 mark]
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
View the QCAA syllabusCompare your working with the guide above.