New View of Natural Selection——The influences from inevitability and occasionality to biological evolution are also discussed

In this thesis, through the analysis to the contradictions between Darvin's Natural Selection Theory and the biological diversity in the present world of nature, and the debate between Darvin's Natural Selection Theory and the Neutral Mutation Random Drift Hypothesis, a new evolution view is created:the unfittest must be eliminated while the biological diversity and differences in quality and quantity exist all the time according to the differences of their fitness. Meanwhile, the influences from inevitability and occasionality to biological evolution are also discussed.