I am answering 2019 Question 2 Genetic variation
My answer below just addresses the first two bullet points os just need feedback on first two bullet points.
I was a bit confused by the marking schedule because the question refers to the gene pool, which would be the North and South Island birds combined. Migration, which is the movement between populations, would result in alleles moving between North and South Island. So migration, in this case, would only result in the increase of genetic diversity (due to new allele combination), not the loss, because the question is in reference to the gene pool as a whole. Alleles are not moving out of the gene pool; they are just moving between populations within the gene pool. The marking schedule is different from my thought process.
Another thing I was a little confused about is marking schuele refer to the 7000 population as small. I was looking online and it says that a minimum of 500 individuals in a population is enough to reduce genetic drift. Marking schedule says the opposite. By NCEA standards what should I consider a small population?
My answer: Allele frequency is the amount of times a particular allele occurs in a gene pool. Gene pool is the total number of alleles present in a population. Migration is the movement of alleles from one population to another.
Migration between the North and South Islands positively affects the karearea gene pool as a whole by increasing genetic diversity. The total population size is 7000, hypothetically we are going to assume 3500 live on the North Island and 3500 live on the South Island. If migration did not occur, then the 3500 birds on each island would just be limited to themself. Now that migration does occur, there are 7000 birds, so there are more mating options which increases genetic diversity and introduces North Island alleles to South Island and South Island alleles to North Island.
Females tend to migrate to new areas, if both males and females stayed in the same area, breeding would be limited to the mates in the areas. With limiting mating partners this would increase the chance of inbreeding which would reduce genetic diversity. Therefore through migration, chances of inbreeding is reduced, which is beneficial to the gene pool.
Genetic drift is the random change in alleles, generally resulting in the loss of alleles. As the population of the karearea is above 500, genetic drift won’t have a significant impact on the population. The random death of an individual is unlikely to completely take out an allele due to the buffer in individuals. If some individual dies, it is easy for the population to return to the original allele frequency through breeding.
Thank you very much any help will be appreciated