Koolen: my apologies for my hasty reply.
Good advice for the future "noticing", but the questions & misconceptions on modes comes up here much too often. The search feature here is excellent, and if ALL posters would avail themselves of it, knowledgable people such as yourself wouldn't have to repost the same thing over and over and over.
BTW, I think that modes can be more easily understood if BOTH methods are taken into consideration. Simply saying that "it's the same scale but you start and end on a different note" can help to get "a" pattern down, but understanding the INTERVALS that distinguish modes of the SAME key and why and when they are used MAY help novices understand a bit better; then again, maybe not.
e.g. Intervals of the modes of C ( where w=whole step or 2 frets , h=half step or 1 fret).
Mode...............Intervals........Notes...............................Scale degrees
C Ionian..........wwhwwwh......C D E F G A B C...............1,2,3,4,5,6,7
C Dorian..........whwwwhw......C D Eb F G A Bb C...........1,2,b3,4,5,6,b7
C Phrygian.......hwwwhww.....C Db Eb F G Ab Bb C.......1,b2,b3,4,5,b6,b7
C Lydian..........wwwhwwh......C D E F# G A B C............1,2,3,#4,5,6,7
C Mixolydian...wwhwwhw......C D E F G A Bb C............1,2,3,4,5,6,b7
C Aeolian........whwwhww.......C D Eb F G Ab Bb C........1,2,b3,4,5,b6,b7
C Locrian........ hwwhwww.......C Db Eb F Gb Ab Bb C....1,b2,b3,4,b5,b6,b7
The intervals remain the same for all of the keys. This applies to harmonic and melodic minor modes also. Then a discussion of WHY & WHEN modes are used ( this can be debated endlessly ) should ensue. The underlying chords will suggest (or demand) a mode (or two or even three) that can be used - again - all this has been posted here before.
Getting the information above to line up exactly is a real pain.
Here's a link that may be helpful and probably a lot clearer than my attempt.
http://www.guitarstuff.com/lessons/lessons.html
[Edited by John O'Carroll on 05-01-2003 at 07:44 AM]