Species of ants resides in a backyard that has very dark green grass. There is a variation of colour within the ants. Most of the ants are black and very few ants are green.
Adaptation
The black ants dominate the backyard as the green ants remain only a few as they are very visible for predictors to eat. This also creates competition for food and resources for the ants.
Differential Reproduction
A few months later, the very sunny weather turns the dark green grass into lighter green. The crows now feed on the black ants as they are easier to spot.
Survival
Overtime the population of the black ants all shorten immensely. However, the green ants managed to maintain their population and survive.
As the time goes on, the green ants are given a selective advantage and are now capable of reproducing much more offsprings to pass on the heritable green colour than the black ants.
The green ants now dominate the yard as they continue to survive. There still are a few black ants, however will not be the same amount as before.