The bass lines can be remembered with "Great Big Dogs Fight Animals" G,B,D,F,A. The first line in the bass is the second G below middle C (circled in red). We "skip" from line to line, skipping a letter in between to find these new notes.
To remember the signal for the lines say "Grrr" like an angry dog. This will help you to recall that "Great Big Dogs Fight Animals", G,B,D,F,A; the bass lines