Aspecies of small lizard has three color forms, pale gray, brown, and black. in its original range, the colors of the rocky environment were mixed from pale gray to very dark, and the population had an even mix of all three color forms. the blending of colors with their environment the lizards hide from predators. a group of these lizards ended up on an island with all gray rocks. eventually, only gray lizards remained. this is an example of