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The mountain pygmy possum (Burramys parvus) is restricted to four regions in Australia’s alpine zone - HSC - SSCE Biology - Question 32 - 2023 - Paper 1
Question 32
The mountain pygmy possum (Burramys parvus) is restricted to four regions in Australia’s alpine zone. The species is listed as critically endangered with less than 2... show full transcript
Worked Solution & Example Answer:The mountain pygmy possum (Burramys parvus) is restricted to four regions in Australia’s alpine zone - HSC - SSCE Biology - Question 32 - 2023 - Paper 1
Step 1
Explain the impact of bushfires and introduced males on population size
Answer
Bushfires have severely affected the population size of the Mt Buller pygmy possum by causing direct mortality. The graph illustrates a decline in population size during years of significant bushfire activity.
The introduction of male pygmy possums from Mt Bogong serves to increase genetic diversity and improve the gene pool of the Mt Buller population, thereby potentially increasing resilience against environmental stresses. Mating with introduced males may also help replenish the population after losses due to bushfires.
Step 2
Discuss the relationship between population size and gene pool
Answer
The population size is intimately connected to the gene pool of the Mt Buller pygmy possum. A small population leads to inbreeding, which reduces genetic diversity and can increase the risk of extinction.
As indicated in the graph, population size fluctuated, but the introduction of new males increased genetic diversity, which is crucial for the long-term survival and adaptability of the population.
Step 3
Identify the effects of genetic drift and bottlenecks
Answer
Genetic drift has played a significant role in the Mt Buller pygmy possum population, particularly during bottleneck events caused by drastic population size reductions from bushfires. The population experienced a bottleneck between 2002-2007, leading to a loss of genetic variation.
The loss of genetic variation through genetic drift can affect the population's adaptability, making it more susceptible to diseases and environmental changes.