The major pentatonic scale also gets its name from being five notes out of the seven notes from the major scale while the minor pentatonic scale has five notes from the minor pentatonic scale. Pentatonic scales tend to sound good despite random orders due to the absence of dissonant intervals between them.
Major Scale As a Diatonic Scale. A major scale is considered a diatonic scale. Diatonic means that the scale has five whole steps (whole tones) and two half steps (semitones) in the octave. Many scales are diatonic including major, minor (the harmonic minor is an exception) and modal scales.
Melodic Minor Scales The melodic minor scale differs from the natural minor scale due the sixth and seventh notes are raised a semi-step, and therefore no longer mirror the major scale. This scale is also some kind of peculiar since it is sometimes played differently ascending and descending.
The natural minor scale can be thought of as a major scale with the 3rd 6th and 7th notes lowered by one half step. By altering these notes we also change the intervals which make up the scale. Also, most of the time when we refer to a ‘minor' scale we're generally referring to the natural minor.