I'm about 7 months into bass playing and I am starting to focus on learning more theory as opposed to just learing tunes. I have picked up the "Bass Grimoire" which has lots of useful information but I am stumped on this one area: They have a section on modes where they go through each Key Signature and the seven "modes" that correspond with them(Ionian, Dorian, etc...) but the "fingering patterns" they show are 12 notes, not the usual 8(octave to octave) I am used to from other sources. I can see that these 8 note scales exist within these 12 note patterns but my question is, why 12 notes and what do they signify? Is it called a "12 note scale"? Should I learn these fingering patterns in addition to the basic 8 (along with pentatonic) I have memorized? Any/all help appreciated as usual..