The seven modes are all constructed from the same major scale notes and yet each one is unique due to the different order of intervals within the mode. Each mode contains five whole tone intervals and two semitone intervals.

Similarities

The following table demonstrates how each mode shares the same notes within the key signature:

I	Ionian		C D E F G A B C	Tonic (Major)
II	Dorian		D E F G A B C D	Supertonic (Minor)
III	Phrygian		E F G A B C D E	Mediant (Minor)
IV	Lydian		F G A B C D E F	Sub-dominant (Major)
V	Mixolydian		G A B C D E F G	Dominant (Dominant 7th)
VI	Aeolian		A B C D E F G A	Sub-mediant (Relative Minor)
VII	Locrian		B C D E F G A B	Seventh/Leading-note (Half-diminished)

Differences

By starting each mode on the same note, it is easier to hear the contrast of how different they sound.

C Ionian

C Dorian

C Phrygian

C Lydian

C Mixolydian

C Aeolian

C Locrian