There is a population of rabbits in this desert. Some are gray and some are tan.
Changes in gene pool
I'm hungry where did they go?
The rabbits that are struggling to survive is the gray ones because they are visible to there predators which are the cheetah and fox. The tan rabbits are surviving because they are blending in with the environment so they are able to reproduce and make more babies.
At this point the tan rabbits will survive and the gray ones will not. Therefor, the tan rabbits will pass those genes onto the next generation.
The gene pool in the population will produce all tan rabbits because the survived the predators by blending in with the environment.