Question

why does genetic drift affect a small population more than a large one?
small populations have more diversity than a large population
large populations have more allele diversity so a dramatic event would result in more loss
the loss of a few alleles caused a large shift in the allele frequency of a small population

Explanation:

Genetic drift is a random change in allele frequencies. In small populations, the loss of a few alleles (due to random events like a small number of individuals not reproducing) can cause a large shift in allele frequency. In large populations, the same random loss of a few alleles has a much smaller impact because there are many more alleles overall. For example, if a population has 10 individuals and 2 with a certain allele die (randomly), that's a 20% change in allele frequency. If a population has 1000 individuals and 2 with a certain allele die, that's only a 0.2% change.

Answer:

The loss of a few alleles caused a large shift in the allele frequency of a small population.