Population Genetics Practice Test

A small, isolated lizard population on a desert outcrop has allele $T$ at frequency 0.52 at a neutral locus. Over 20 generations, with no immigration and no detected genotype differences in survival or reproduction, $p(T)$ fluctuates unpredictably between 0.30 and 0.70. The census population size remains around 80 adults each generation. Which factor most directly explains these allele frequency fluctuations?

A large insect population has allele $K$ at frequency 0.55. After a pesticide is introduced, genotype fitness estimates show $KK$ has the lowest survival, $Kk$ is intermediate, and $kk$ has the highest survival. Over eight generations, $p(K)$ decreases to 0.18. No immigration occurs, and the mutation rate is unchanged. Which factor most directly explains the decline in allele $K$ frequency?