Genetic Drift
Genetic drift is the reduction of genetic variation due to random chance. In the comic strip below, I tried to demonstrate genetic drift, specifically the founder effect, by showing how, by random chance, three random spiders are blown away by a tornado and land on an island, then reducing genetic variation and fixating on the SZ allele. An example that would not be genetic drift would be if the original generation of spiders were to all turn red due to predators which would then be natural selection.