Principle #1: Genetic Variation: There is two types of bears in the Artic. Some with thick fur and others with thin fur. The ones with the thick fur are in the water and the ones wit thin are on the ice.
Principle #2: Overproduction & the Struggle for Existence: The Polar bears with the thinner fur struggle to survive and only go on the ice because of the extreme cold weather.
Principle #3: Differential Survival & Reproduction: The bears with the thick fur will reproduce and have more than one cubs with thin fur because they will learn to survive and hunt in the harsh climates.
Principle #4: Changes in the Gene Pool: The change in the gene pool will be more of the bears with the thick fur.