Dodece,
The truth is that you have the relationship backwards.
We don’t require evolution to understand anatomy, an understanding of anatomy is required to understand evolution. You can catalogue and study the differences between two specimens, understand how these organisms worked, and map the genetic make-up of both creatures without acknowledging evolution; but you require the knowledge from these fields to argue that one species evolved into the other. You can discover fossils of extinct species, create a time-line for their extinction without ever assuming that it evolved into anything (because lots of species would have been a short lived unsuccessful branch); but without this fossil record you can’t argue that evolution exists.
Evolution is a big-picture theory, and (like most big picture theories) it is used as a way to make sense of what would otherwise seem like chaos. Much like I could doubt the big-bang theory and accept that the universe exists, people can doubt the theory of evolution and still accept that the findings of all these other fields are still valid. Where you’re differing is how you explain how all these pieces of science work together to support your big-picture theory; and if creationists want to explain that god was constantly tweaking the animal-life make-up of the planet and introducing and eliminating species at an alarming rate over the last 7,000 years that’s there (somewhat insane) choice.
