How does evolution change animals?
Evolution changes animals to better fit their environment.
Evolution can be defined as simply change or change within a species. This type of adaptive evolution is easily observed in nature.
Humans in Denmark and Iceland have genetic mutations that allow them to be better adapted to the environment of the cold darker environment where they live. The white skin allow for more absorption of sunlight creating vitamin D. This provides the lighter skinned people an adaptive advantage.
A population of squirrels was separated by the formation of the Grand Canyon of Arizona. The squirrels on the north rim where it is colder have evolve a thicker fur, and are larger than their cousins on the south rim where it is much warmer.
While it is clear that animal populations can change to adapt to the environment this form of evolution is the selection of mutations and variations best suited to a particular environment. White skin is actually a harmful mutation, in most environments. Sunburn, Skin Cancer are much more prevalent in white skinned people than the general population.
There is actually no direct empirical evidence that evolution ( of any kind) is capable of changing one type or kind of animal into another type or kind.