animals with better genetics will survive more often than animals with poor genetics that cannot benefit them. for example: if there were mice that lived in a desert with orange sand, orange colored mice would be more likely to live because they blend in with their environment and can hide from predators. on the contrary, mice of colors that stand out from the orange sand like black or white mice will be less likely to survive because predators can spot them easier. (the color of the mouse is based on genetics)