优胜劣败

Explanation: Refers to the biological survival of the competition in the preservation of adaptable, poor adaptability to be eliminated. This is a fundamental point of Darwinian evolution. 　　Usage: Joint type; as predicate, object; containing derogatory 　　Source: Qing Wu Jian "pain history" first round survival of the fittest, death to take random insult, since no need to say. " 　　Examples: In human society, ~ the phenomenon of frequent occurrence.