Ummm...mutation and natural selection are part of the theory of evolution that Darwin proposed.
The problem is that neither mutations nor natural selection can produce a new kind of animal, only variations within a species. Besides to have a new species, you have to have NEW genetic information implanted. Mutations and natural selection take genetic information away from an organism or damages genetic information already inherent in the organism itself.
Genetics is no friend of evolution
All observational science shows devolution of the species, not evolution of the species.