Let me see if I can answer this question with information that Darwin didn't have during his days which makes me, if I think about it, more educated than Darwin. We have the genetic code and both sides agree with that. The creationists model says that a creator created the original forms in their original condition, fully formed, beetles, wolf, horse, human, rabbit, etc... And inside these original forms was the genetic make up for diversity of species but limited to their original forms. Meaning the original forms can take on different characteristics and variety but only in their same original forms. They don't take on any other form. Non-coincidently that is what we see in nature.