Natural selection and mutations are scientifically observed daily. Creationists welcome observations related to natural selection and mutations. In fact, these mechanisms of biological change help to explain the biblical concept of “kinds” of animals.
Baraminology is the study of “kinds” as described in the Bible. Learn more about it HERE. In a nutshell, a kind is sometimes the same as a species and sometimes it is broader, like a family of species. In either case a kind of animal has a great deal of variability in its genetic code.
With natural selection and artificial selection (breeding) you can get a variety of features in dogs. However, each kind has limits to how much change it can produce. Dogs can have various colored coats and eyes, length of legs and hair, ears that stand up and ears that flop over but we cannot breed dogs for wings, gills, human-like fingers or scales. Dogs don’t have the information for those features in its DNA.
I believe that God created animals “after their own kind” and that He did not use evolution. After the kinds were created there were a variety of changes, as allowed within each animal’s genetic code.