Field mice in beach mice are closely related species. The Field mice are various shades of brown in the beach mice or later 10 and beige. Each piece is quite well camouflage in their home environment, where they blend into their surroundings and invade their major predators (flying raptor birds such as hawks.) these two species live in joining habitats(a Field near a beach), but don’t normally wander into the other habitat. One day the entire field is mold down, so that a new housing development can be built. The Field mice are displaced, and a scare everywhere, including onto the beach where they are fees for some vigilant hogs. As you may imagine, many of the Field mice get eaten. Some of the lighter colored ones escape predation and are able to successfully live on the beach and reproduce with other field mice. In this scenario, the process of natural selection is acting on

As the problem shows, the field mice are the ones that natural selection is acting on, but only the ligher shade ones. Because the lighter shade individuals are more likely to survive in the beach because they blend with the environment.

Evolution occurred on the field mouse population because if you read the script in the end, they were able to successfully reproduce. This means that they evolved in such a way that they were able to survive in their new environment. (most likely carrying on the trait of light-colored fur)

Natural selection acts on traits, phenotypic traits, favorable to the environment. Evolution occurred because of the natural selection, because the favored trait enabled the organism to adapt to the environment.