QUESTION 7 (3 marks)
Koalas were once widespread in Australia. Due to a variety of factors, their population decreased and fragmented into small pockets, forcing them to inbreed. They have recently been hit by devastating epidemic diseases. Explain why koalas face an increased extinction risk from disease.
QCAA guide · typeset solution
QCAA sample response and mark allocation
7 | High genetic diversity may allow for some members of the population to survive diseases and later reproduce and pass on their resistance to increase the survivability of the population. However, inbreeding creates low genetic diversity, which makes koalas vulnerable to extinction due to disease. | • explains how genetic diversity can prevent extinction during rapid environmental change, e.g. disease [1 mark] • describes why koalas have low genetic diversity (inbreeding) [1 mark] • states that koalas are more vulnerable to extinction due to low genetic diversity [1 mark] |
QCAA sample response and marking criteria reproduced from the official guide.
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