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Genetic Variation & Change · Part 4 of 4
9 exam-style questions with model answers, plus 12 quick multi-choice questions — every question on this part of the standard, grouped by the 3 pages of notes they come from.
Write a full answer before you reveal the model one. That comparison is where the learning happens.
Define natural selection, and state what must already be present in a population before natural selection can act.
A bacterial population is treated with an antibiotic. Within months, most of the bacteria are resistant. Explain how this happened.
Many NZ native bird species have declined severely since the arrival of introduced mammalian predators, rather than adapting to them. Discuss why natural selection has not rescued these populations, and what this reveals about the limits of natural selection.
Explain how migration can change the allele frequencies of a population, and state the condition that must be met for it to have any effect.
Two nearby populations of a beetle have very different allele frequencies for wing colour. A new road is built, physically separating them. Explain what will happen to the two gene pools over time.
A conservation manager is deciding whether to translocate kākāpō between two island populations. Discuss the genetic arguments for and against, and evaluate what would make the decision sound.
Define genetic drift, and explain why it has a much greater effect on small populations than on large ones.
Explain the difference between a genetic bottleneck and the founder effect, and explain what both have in common.
Two populations of a NZ skink have the same allele frequencies for a colour gene. One lives on the mainland with 50,000 individuals; the other on a small island with 60. After 50 years, the island population's frequencies have changed dramatically while the mainland's have barely moved. Discuss the likely cause, and evaluate whether natural selection could account for the difference.