Generation 1 These dark green beetles live in a forest and eat decaying animals and plants.
Generation 2 After breeding, one beetle has mutated a gene that causes its offspring's shell to be brown.
Predator Interruption The brown beetle lives longer than the green beetles because its new shell color helps it hide from predators. A longer lifespan helps it breed more than the green beetles do.
Generation 3 After breeding, the brown beetle produces offspring that carry the brown shell causing gene.
Predator Interruption The offspring of the brown beetle survive predators, live longer, and breed more than the green beetle offspring.
Generation 4 The offspring of the brown beetle breed and produce offspring that are more adept at avoiding predators of this environment. Now the general beetle population has evolved brown shells for camouflage.