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Rock wallabies, Petrogale lateralis pearsonii, on Pearson Island off the coast of South Australia have had no genetic contact with mainland rock wallabies since they were isolated by rising sea levels at the end of the last glacial period, around 10,000 years ago - VCE - SSCE Biology - Question 8 - 2004 - Paper 1
Question 8
Rock wallabies, Petrogale lateralis pearsonii, on Pearson Island off the coast of South Australia have had no genetic contact with mainland rock wallabies since they... show full transcript
Worked Solution & Example Answer:Rock wallabies, Petrogale lateralis pearsonii, on Pearson Island off the coast of South Australia have had no genetic contact with mainland rock wallabies since they were isolated by rising sea levels at the end of the last glacial period, around 10,000 years ago - VCE - SSCE Biology - Question 8 - 2004 - Paper 1
Step 1
a. Explain how a genetic bottleneck may lead to a decrease in genetic diversity.
Answer
A genetic bottleneck occurs when a population experiences a significant reduction in size due to environmental events or other pressures, leading to a loss of genetic diversity. This reduction causes the surviving population to have a limited gene pool, resulting in a situation where allele frequencies can change by chance rather than by natural selection. Consequently, this random fluctuation can result in some alleles being lost while others become more common, diminishing the overall genetic variability of the population.
Step 2
b. Suggest one reason for the wallabies’ success despite the lack of genetic diversity within the population.
Answer
One reason for the wallabies’ success could be that they are well adapted to their specific environment on Pearson Island, allowing them to thrive despite a low level of genetic diversity. Additionally, the absence of significant predators may contribute to their stable population, facilitating survival and reproduction.
Step 3
c. Give one reason for this suggestion.
Answer
Introducing individuals from the southern Western Australian populations may increase the genetic diversity of the wallabies, which could enhance their adaptability and resilience to environmental changes, improving their long-term survival prospects.