Evolution by inheritance of acquired characteristics predicts that the mice in the different environments needed to change color, so they did so and then passed their traits on to their offspring. The theory of evolution by natural selection is not goal oriented. It predicts that white and brown mice are descendants of an ancestral population that varied in color. The white mice had higher fitness in the beach environment, where they were more likely to escape the notice of predators. Likewise, the brown mice had a higher fitness in the mainland environment.