One of the modules in the Master Spinner Level One workbook has you look at an entire fleece and study it. Now, I had originally thought "A sheep is a sheep is a sheep". And that idea went straight out the window when I attended Fibre Week last year. During the class last year we looked at individual fleeces, and kind of examined them section by section. But it wasn't until I sat down and did the module that really showed me just how varied a fleece can get! The staple length varies, section to section. As does the crimp structure, and the texture, and even the lock structure.
So the next time you get a whole fleece, dump the whole bag out on your kitchen floor (because it's going to be a dirty process) and look. If your fleece was bundled up nicely, chances are you can un roll it and see just how it came off the animal. I'm guessing you'll be as surprised as I was!