In a world that has not physically changed and in which has not arisen new species of animals or plants, the extinction would not be known. Each available niche inside the ecology world would be filled with a constant population of diverse animals (depredators and its preys) in a balanced vital cycle without changes. However, the natural ecological balances have always a dynamic character, and they tend to change in the time. In fact, those changes are inextricable part of the mechanism of the evolution: When an evolutionary base of extinction is made, it is unavoidable.
