Scalar Bass Lines: Scalar bass lines offer more possibilities than chordal bass lines. Lines with stepwise motion are more "walking-like" than chordal lines, wich tend to "leap". In order to retain the sound of each chord, chord tones are generally played on beats 1 and 3 (the strong rhythmic/harmonic beats), with passing tones, neighbor tones, and other melodic devices being used on beats 2 and 4 (the weaker rhythmic/harmonic beats).
A Bass lines using both diatonic and chromatic passing tones on beats 2 and 4
Bop Scales: The mixolydian bebop scale places a passing tone between the flat fth and root, allowing chord tones to land on strong beats. this can be applied to walking lines as in chorus two.
To create logical scalar bass lines, it is essential tu use strong voice leading. In this Chorus each note moves logically and smoothly to the next.