How important that I know this? I feel like the AP biology book has a million definitions with respect to this section, do you really think I need to know them all?
I'd say you should definitely know at least 75% of the terms presented in the Cliffnotes AP Bio book. Many of those terms tend to resurface on the exam.
If you think learning all of that material is worth hopefully getting 2 questions right, go for it. If not, just learn the basics (chart on dat qvault) and hope for the best.
I think learning the taxonomy stuff in Cliff's Bio is manageable if you don't try to do it all at once. Try learning just a section of it a day along with a different bio chapter. It all gets jumbled if you take in too much.