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Question 6 To estimate the amount of genetic variation in a species, measures of the average heterozygosity at a number of different gene loci in that species are made - VCE - SSCE Biology - Question 6 - 2002 - Paper 1
Question 6
Question 6 To estimate the amount of genetic variation in a species, measures of the average heterozygosity at a number of different gene loci in that species are ma... show full transcript
Worked Solution & Example Answer:Question 6 To estimate the amount of genetic variation in a species, measures of the average heterozygosity at a number of different gene loci in that species are made - VCE - SSCE Biology - Question 6 - 2002 - Paper 1
Step 1
a. Which organism would you expect to show the most phenotypic variation? Explain.
Answer
Drosophila would be expected to show the most phenotypic variation since it has the highest average heterozygosity at 12%. Heterozygosity indicates the presence of multiple alleles at a gene locus, which can result in diverse phenotypes. In comparison, the other organisms, such as the elephant seal and cheetah, exhibit much lower heterozygosity, suggesting that they have less genetic diversity and therefore are likely to show less phenotypic variation.
Step 2
b. Lack of genetic variation is believed to put a species at greater risk of extinction. Explain why low levels of variation put a species at risk of extinction.
Answer
Low levels of genetic variation reduce a population's ability to adapt to environmental changes. If all individuals in a population are genetically similar, they may respond to changes in the environment, such as disease or climate shifts, in the same way. This uniform response may lead to widespread susceptibility to threats. For example, if a disease infects a population, all individuals may be equally vulnerable, resulting in a higher risk of decline or extinction.
Step 3
c. Explain what is meant by the founder effect in the context of population genetics?
Answer
The founder effect occurs when a small number of individuals establish a new population. The genetic diversity of this new population is limited to the alleles present in the founding members, which may not represent the genetic diversity of the original population. This can lead to reduced genetic variation and increased vulnerability to environmental pressures and diseases, affecting the population's overall survivability.