There is a population of frogs living in a pond, 25 are green, 25 are brown, 25 are yellow with green spots and 25 are all yellow. A drought occurred and 75% of the frogs died, with the remaining frogs green and brown. After 25 generations the frogs still were green and brown, and yellow frogs never appeared in the population again. Which of the following best explains this phenomenon?
Multiple Choice
Balancing selection.
Heterozygote advantage.
Founder effect.
Bottleneck effect.
Sexual selection.