How is natural selection related to organic evolution?

Answer 1

Natural selection is the critical part of evolution following random mutation. It is by natural selection that organisms can exploit new food niches or new territories. Mutations are random. Those that are detrimental to the organism die out. Those that are beneficial get passed on. Those that are neither beneficial nor detrimental also get passed on. Should a benign mutation become beneficial due to changing circumstances then natural selection will favour it.