Then how do we explain why some creatures seem to undergo 'evolution' or random mutation/natural selection, and some don't?
One of the reasons why I’m a young earth creationist is because I don’t believe the evidence suggest any species have evolved via random mutation. As a YEC, I do acknowledge limited change within the boundary of the created kinds over time, but I have yet to see any evidence, other than evo-assumptions, that suggests that random mutation plus natural selection is capable of macroevolution.