Imagine a change in the iguana's habitat from dry land to aquatic. Based on the Generation I allelic frequencies, we can assume only a small percentage of iguanas had webbed feet and were able to survive. Over many generations, if their habitat remains aquatic, iguanas without webbed feet will disappear from this population.
This is an example of Darwin’s concept of survival of the fittest. The animals with traits suitable for the environment will live and reproduce and pass on their traits. Soon the species will evolve to the new environment.
