Evolving Music

This trope refers to songs that have lyrics or music that change significantly depending on who is in the group or if the singer goes solo. They may do their own version of songs they originally performed with the band but keep the same tune and probably the same lyrics.

They may also be a song about a particular event in the writer's life; the lyrics may change if the situation changes.

Groups may also decide to change the lyrics or arrangement of a song even if there hasn't been a change, just to keep it fresh or if they decide to go in a new direction artistically.

If a TV show is a Long Runner this may happen to the opening theme between series, though generally these only affect the music, and any lyrics will be unchanged.

Theatrical productions may also change some elements depending on the country it is being performed in: for instance, if a lyric refers to someone who is well known in the show's home country but is an unknown in other parts of the world. Equally, if a show has a modern setting and refers to current events, then lyrics and lines may change once those events are no longer in the news.

Compare Evolving Credits.

Note: The TV example does not apply if a show has totally new music for a new season like Bleach; only if it's a new version of the same music.

Anime & Manga

 * Angel Beats applies this trope to its opening theme in episode 4. Theme of SSS also got an epic rock arrangement which is used in tenser situations.
 * Neon Genesis Evangelion used different versions of In Other Words better known as Fly Me To The Moon as its ending theme.
 * Fresh Pretty Cure and Suite Pretty Cure both remixed their theme songs after their respective Sixth Rangers' debuts.
 * In addition, the opening theme of Futari wa Pretty Cure Max Heart is a remix of the original Futari wa Pretty Cure theme.
 * Sailor Moon switched to a different cover of its opening theme for its third and fourth series (and used a different theme entirely for the fifth).
 * The World God Only Knows has the respective capture targets doing the ending song when they're in their own story arc.
 * Infinite Stratos whenever one of the five girls entered the harems their seiyuu would join in and sing the ending.

Film

 * The James Bond theme.

Live Action TV

 * Coronation Street
 * The Cosby Show changed theme song every year. It was the same tune, but it was arranged in a different musical style every time.
 * The original recording of Doctor Who's theme tune went under subtle changes from 1963 to 1980 before being done from scratch in later years. All Doctors apart from the Fifth have had a new piece of music arranged for them.
 * Eastenders
 * The Law and Order shows all have the same Theme Tune with different tweaks to the arrangement so viewers can tell the main show from SVU, Trial By Jury, or Criminal Intent.
 * Mystery Science Theater 3000. is a handy flowchart tracking all the permutations of the theme music.
 * The OC's theme song got longer after the first few episodes, as some actors who were originally just guest stars got contracts and had to be added to the credits.
 * Quantum Leap had its theme music remixed for the fifth and final season.
 * Star Trek Enterprise had the widely derided theme song "Where My Heart Will Take Me", which was remixed with more of an upbeat rhythm for the third season, apparently in the hopes that this would make people somehow like it.
 * After Czechoslovakia split into Slovakia and the Czech Republic in 1992, the theme song to Where in The World Is Carmen San Diego changed an instance of "Czechoslovakia" to "Czech and Slovakia".
 * Survivor did this throughout the first twenty seasons with its theme "Ancient Voices." Each season's version had different vocals and elements that usually corresponded to the country where the season took place (a gong in Survivor China, a didgeridoo in Survivor Australia, etc.). Season twenty-one, Survivor Nicaragua, averted this by returning to the first season's version.
 * Power Rangers ZEO used a remix of the Mighty Morphin Power Rangers theme tune with new lyrics. Power Rangers Samurai uses another remix, which adds the line "Rangers Together Samurai Forever", and removes all references to "Mighty Morphin". The seasons in between are not an example of this trope, as they had completely new theme tunes.
 * Power Rangers Turbo also had a remix of mighty morphin's tune titled "new rangers to the rescue" during The Movie. the symphonic version played a few times during the season, but without the changed lyrics it's hardly different enough from the origional for people to notice without being told.

Music
"Even if the battle is won
 * The Beatles have done this. The songs of Let It Be... Naked are mostly evolutions of songs from the original Let It Be.
 * "Across the Universe" has two different arrangements from the classic era -- one from Let It Be, and the one currently on Past Masters.
 * "Revolution" and "Revolution #1" are another fast evolution of the same song.
 * Paul McCartney has also done this as a solo artist, both to his own works and to Beatles songs. He loves remixes...
 * Paul's Unplugged: the Official Bootleg is mostly these.
 * Dramatic example: "Coming Up" from McCartney II (with "The Plastic Macs") vs. the live vs. of "Coming Up" on Wingspan, vs. modern live vs. (which include long drum solos).
 * Some of the songs on the Give My Regards to Broad Street soundtrack fall under this. For instance, "Ballroom Dancing" has an entire extra verse from its original "Tug of War" vs.
 * The Butthole Surfers' "Some Dispute Over T-Shirt Sales" is essentially Ministry's "Jesus Built My Hotrod" (which their vocalist Gibby Haynes provided lead vocals for) with a different guitar riff: It uses the same melody and Singing Simlish lyrics.
 * Eric Clapton did this with "Layla." First he performed it with Derek & the Dominos. Then, when he did a solo unplugged performance for MTV, he did a much slower and soulful rendition of it.
 * Counting Crows have changed some of the lyrics to their song "Mr Jones" -- the song was written before they had their first hit, and has lyrics about wanting to be big stars; the new lyrics are about looking back after having been big stars and realising that it's not all it's cracked up to be. They also perform the song in a quieter and less rocking tone.
 * Dennis Culp wrote a song about rhubarb pie for Five Iron Frenzy, but the band ended up using that music for some completely different lyrics that Reese Roper wrote, "Ugly Day". "Rhubarb Pie" was released later on their B-sides album.
 * Every song ever performed by Bob Dylan.
 * E from Eels seems to relish dramatically different live arrangements for older songs - for instance, the Daisies Of The Galaxy version of "I Like Birds" is laid-back and based around acoustic guitar, but at some point they started doing a much faster, noisier electric version live, and have kept playing it that way every since. During the Eels With Strings tours even songs that were originally fast paced rock or upbeat pop were played slower and more stripped down (and of course, with a string quartet).
 * Several songs from Genesis:
 * "Watcher of the Skies" would only be performed without lyrics after Peter Gabriel's departure. It would later be dropped from the setlist entirely as it only sounded good on one piece of equipment (the Mark II Mellotron it was recorded on).
 * "Firth of Fifth" would have its piano intro dropped on account of it being impossible to play on contemporary digital pianos. It would later have its lyrics dropped on account of them being crap.
 * Phil Collins recorded an alternate version of "Behind the Lines" on his first album, then played that version on his first solo tour.
 * Several songs from The Lamb Lies Down On Broadway were reworked versions of songs from their salad days that were written on the road, played live, and then dropped after a few shows.
 * For the band's final two tours, most songs would be transposed into lower keys to accomodate Ray Wilson's voice and later the changes to Collins' voice.
 * Kylie Minogue is very fond of this. Many of her live shows after her 1998 Intimate And Live Tour. She has changed her song 'I Should Be So Lucky' to both a ballad and an electronica song. She also turned her song 'I Believe In You' into a ballad and 'The Locomotion' into a jazz song.
 * Mogwai's signature song, Mogwai Fear Satan, has changed drastically between its spot on their current live set.
 * Morning Musume's "Joshi Kashimashi Monogatari" has several versions due to the song's verses being about the people in the group but the groups has a tradition of regularly adding and shedding members meaning the lyrics have to keep evolving.
 * "Joshi Kashimashi Monogatari" was also given a Cover Version by Hello Project Elder Club but that also had two versions as the two tours had different members in attendance. In 2011 Dream Morning Musume formed and their first song is yet another version of JKM.
 * Muse have recently revamped "Cave" from their 1999 debut album, Showbiz, giving it a new piano arrangement when playing it live on their Resistance Tour.
 * Oingo Boingo also did this a lot: many of their songs were written when they were still a circus band instead of a rock band, and some of them were brought back later with rock arrangements. (Lead singer Danny Elfman also re-used one of the band's old circus songs as the theme song for the Dilbert cartoon.)
 * Amanda Palmer also changed all of her Dresden Dolls song arrangements and some of her lyrics after going solo.
 * She changed her arrangements anyways; since she didn't know how to read sheet music, she completely played by the ear. Naturally, it was amazing.
 * The Pet Shop Boys do this with "Being Boring" in live shows since the Turn of the Millennium: the lyric eulogizing friends that died of AIDS changes from "All the people I was kissing/Some are here, and some are missing in the 1990s" to the less dated "All the people I was kissing/Some are here, and some were missing by the 1990s".
 * The Tiger Lillies do this a lot. Their lyrics, arrangements and stage antics are constantly changing, and it's interesting to see how much their songs evolve and grow over time.
 * It happened over a relatively short period of time, but Weezer's "Burndt Jamb" went from having Singing Simlish lyrics in one publicly released demo, to a full set of lyrics in another demo, to a completely new set of lyrics by the time it was officially released on Maladroit. There's also "Private Message", which had its lyrics substantially rewritten and became "Hand To Hold" by Brian Bell's side project The Relationship, and "Thought I Knew", which conversely went from being a slow minor key Relationship song to a faster, major key Weezer song.
 * Frank Zappa's entire career was marked by this, something he referred to as "Conceptual Continuity." Pieces of lyrics and melody, and sometimes entire songs, would pop up in different contexts and arrangements on various albums. As an example, he released no less than three versions of "Peaches en Regalia", each sounding quite different.
 * In the 80's, Neil Young re-recorded his earlier Buffalo Springfield song, "Mr. Soul," as part of his synth/vocoder-based album Trans. This was motivated by his desire not to stagnate as an artist and his interest in recreating the experience of communicating with his cerebral palsy-afflicted son.
 * The Bangles have several examples:
 * When Vicki Peterson wrote "Single By Choice," it was a pretty personal song for her. After getting married to John Cowsill in 2003, she jokes about doing a "Married By Choice" version.
 * Vicki's songs seem especially prone to this trope. She wrote "Lay Yourself Down" (which appears on Sweetheart of the Sun) for her fiancé Bobby in 1990, as he was struggling to find his place in the music business. The song and its lyrics like those below became even more personal and poignant when Bobby began a battle with leukemia (to which he eventually succumbed in 1991):

The war is not over

It’s only begun

If there’s one still standing

One still standing his ground

Don’t you lay yourself down"


 * "Walk Like An Egyptian" has a different evolution. Debbi Peterson's drumming was replaced by a drum machine on the hit single, and in a particularly egregious case of Executive Meddling, she was even left out of the vocals. Now, when the group performs the song live, Debbi's drumming still gives way to the drum machine, but she sings and plays acoustic guitar.
 * Radiohead do this a lot, both intentionally and accidentally, and in a variety of ways.
 * The most obvious example is that, following their dramatic shift into more experimental, electronic styles following Kid A, they found a lot of their songs either very difficult or even impossible to perform live, which resulted in radically different interpretations being performed on tour. Their live album, I Might Be Wrong, was released to give fans who missed out on the live shows an (official) opportunity to hear these new arrangements.
 * The opposite is also true, as they often demo new songs live as they're being written. The most extreme example probably being Reckoner. Originally debuted during their 2001 tour as an aggressive (and decidedly sloppy) Grunge number, it wouldn't see an official release until 2007's In Rainbows, where it was a completely different song. During the writing process they decided they preferred an unheard bridge and scrapped all the original music and lyrics and started over. The 2001 version would later be released by Thom Yorkes solo project as Feeling Pulled Apart By Horses, though still in a radically altered style.
 * Having been together as a band for quite a while now, they've also developed various ways of keeping the songs interesting for themselves. During live performances of "Everything In It's Right Place", Thom Yorke has started adding in lines from other peoples songs (often the chorus from If You Tolerate This Then Your Children Will Be Next by Manic Street Preachers). As Jonny plays a radio for several songs (notably "Climbing Up The Walls" and "The National Anthem") each performance will, naturally, be entirely different, and he usually tunes into a chat show in the countries native language. He's also been known to add in pre-recorded phrases to be manipulated live on his sampler during certain songs, often "Happy Birthday X", to mark said band members birthday.
 * Nelly Furtado's "Say It Right" has a proper guitar solo in live performances instead of the short, repetitive riff of the studio version.
 * Yellow Magic Orchestra has recorded several live and studio versions of the songs from their first album, with "Behind the Mask" being played with its original lyrics and the ones Michael Jackson wrote for the song when he chose to cover it.
 * Orbital have done this a lot, but their track "Haclyon" has been a particularly striking example - the 1994 "+On + On" version familiar to most listeners is itself a development of the 1993 original, but soon after its release, they started incorporating a sample from Belinda Carlisle's "Heaven Is A Place On Earth" into their live performances. Some time after that, they also threw in bits of "You Give Love A Bad Name" by Bon Jovi. Since then, the track has mutated even more, its original darkness morphing into a euphoric unofficial remix of "Heaven Is A Place On Earth". It's still a highlight of their live shows, but liable to come as rather a shock to anyone who just knows the studio version.
 * Dutch national treasures The Nits have made evolving music into something of a trademark, with some songs undergoing radical rearrangement for every tour. Sometimes songs are rearranged because of line-up changes, but mostly it's done just because they can.
 * Five Man Electrical Band has two versions of I'm A Stranger Here and Signs, though all that's really different is one line taken out in the former and the intro shortened in the latter.

Literature

 * The Hedgehog Song from Discworld novels. See, only the hedgehog... is immune to certain kind of abuse, but there are too much of other animals to list, so the singer usually just picks any that springs to the mind.
 * The protagonist of Finder's Bane sang "The Toasting Song", where all couplets have in common only the meter and "We toast..." in the first line. Hilarity Ensues when one joking couplet he made up.
 * In-universe example in Holes -- the lyrics to the pig song get changed from the original Latvian when sung in English so that they still rhyme and preserve much of the original meaning.

Theater

 * The climactic song of Avenue Q "For Now" used to include the line "George Bush is only for now" since he left office it has been changed... to "George Bush was only for now" or "Glenn Beck is only for now" or "Fox News is only for now".
 * The London production used to have the line above, but it has since changed to "Gordon Brown is only for now", as of writing Gordon Brown had just resigned as PM so expect yet another change in the near future.
 * Various regional performances will have different changes to that line.
 * Depending on what production, Christmas Eve might say "Chinese Restaurant" instead of "Korean Deli" during It Sucks To Be Me.
 * More recent productions tend to change 'Mix Tape' to say 'Mix CD' or 'CD' as often as possible given the change in syllables or meaning.
 * Spamalot changed the lyrics of A Divas Lament - in which the female lead mentions not having won any awards - after the show did quite well at the Tony awards.
 * "As someday it may happen / I've Got a Little List", High Executioner Ko-Ko's song from Gilbert & Sullivan's The Mikado, is basically a humourous list of "undesirables" that can be updated with more current references for contemporary audiences.

Video Games

 * The Gran Turismo series has this opening theme, Castle Over the Moon, which becomes more and more awesome as the series progress.
 * The Comet Observatory and Starship Mario themes from Super Mario Galaxy and Super Mario Galaxy 2, which both gain more instruments as the game progresses.
 * Yoshi's Island did a similar thing with the map theme.
 * Also, those games' takes on "Road to Bowser" from Super Mario 64, with more smoother music for Galaxy and a choir for Galaxy 2.
 * When "Luna Ascension" from Tower of Heaven was reused in Super Smash Land, it was redone to have a more authentic Game Boy sound, as well as the addition of a remix of "Pillars of Creation" after the second loop.
 * In Sonic Rush Adventure, the Windmill Village music is remixed each time you craft a new vehicle, becoming faster-paced and gaining more instrument lines.
 * In Ristar, the first stage of Planet Sonata has some fun with this. You have to wake up giant sleeping birds who sing to rebuild the background music.

Western Animation

 * In addition to changing the visuals of the theme song every season, South Park has also switched between several different remixes of its main theme.