1. Pokemon with 3 stages evolve more in the Anime.
Evolutions of Pokemon with 2 stages = 16
Evolutions of Pokemon with 3 stages = 43
This is true, however:
1. The main characters had more Pokemon with 3 stages of evolution than 2.
2. Pokemon with 3 stages of evolution can evolve twice as much as those with 2.
3. Not all the Pokemon with 3 evolutionary stages fully evolved.
2. There are more under-evolved Pokemon that have 2 evolutionary stages.
Under-Evolved Pokemon with 2 stages = 23
Under-Evolved Pokemon with 3 stages = 18
This is true, however:
1. Many Pokemon with 3 stages of evolution (currently in their second stage) haven't fully evolved just like those Pokemon of only 2 stages.
2. Some Pokemon don't evolve because they have become iconic like Meowth (who hates Persians and so doesn't want to evolve), Pansage (who needs a stone to evolve and some people just can't be bothered) and Mime Jr. (who technically should have evolved - this shows you that script writers really don't want some Pokemon evolving).
3. A lot of Team Rocket's Pokemon don't evolve a lot of the time because they don't train but rather sit in their Pokeballs as Team Rocket plans how to capture Pikachu and when they do fight they faint easily because they don't have a strong enough connection with Jessie/James
Main Characters' Pokemon that evolve:
Yanma → Yanmega - Jessie - 0 episodes - After using Ancient Power
Caterpie → Metapod - Ash - 1 episode - After defeating Jessie's Ekans and James's Koffing
Metapod → Butterfree - Ash - 1 episode - Protecting Ash from wild Beedrill
Magikarp → Gyarados - James - 1 episode - Angry at James for releasing it
Piloswine → Mamoswine - Dawn - 2 episodes - Fighting Team Rocket after learning Ancient Power
Charmeleon → Charizard - Ash - 3 episodes - Fighting a wild Aerodactyl
Silcoon → Beautifly - May - 4 episodes - With Jessie's Cascoon
Cascoon → Dustox - Jessie - 4 episodes - With May's Silcoon
Sewaddle → Swadloon - Ash - 5 episodes - Fighting Burgh's Whirlipede
Wurmple → Cascoon - May - 10 episodes - With Jessie's Wurmple
Wurmple → Silcoon - Jessie - 10 episodes - With May's Wurmple
Starly → Staravia - Ash - 11 episodes - Fighting Team Rocket
Snorunt → Glalie - Ash - 15 episodes - Fighting Team Rocket
Swinub → Piloswine - Dawn - 20 episodes - Fighting Team Rocket
Pidove → Tranquill - Ash - 20 episodes - Fighting wild Venipede
Gligar → Gliscor - Ash - 21 episodes - Saving Ash from a fall after grabbing a Razor Fang
Roggenrola → Boldore - Ash - 27 episodes - Fighting Clay's Excadrill
Koffing → Weezing - James - 29 episodes - Out of love for James
Along with Jessie's Ekans
Ekans → Arbox - Jessie - 29 episodes - Out of love for Jessie
Along with James's Koffing
Golbat → Crobat - Brock - 31 episodes - Fighting Team Rocket
Monferno → Infernape - Ash - 31 episodes - Fighting Team Rocket and protecting several Pokémon
Charmander → Charmeleon - Ash - 32 episodes - After fighting a group of berserk Exeggutor
Fletchling → Fletchinder - Ash - 33 episodes - Fighting Nami's Talonflame
Poliwag → Poliwhirl - Misty - 41 episodes - Fighting Ash's Bulbasaur
Lombre → Ludicolo - Brock - 42 episodes - Pulled a Water Stone out of Samantha's bag
Tranquill → Unfezant - Ash - 46 episodes - Fighting Skyla's Swanna
Bonsly → Sudowoodo - Brock - 49 episodes - After escaping Team Rocket shortly after learning Mimic
Cyndaquil → Quilava - Dawn - 49 episodes - Protecting Dawn and Shinko from a colony of Ariados.
Lotad → Lombre - Brock - 51 episodes - After falling into a well
Dwebble → Crustle - Cilan - 51 episodes - Fighting Team Rocket
Swadloon → Leavanny - Ash - 51 episodes - Fighting Iris's Emolga
Treecko → Grovyle - Ash - 59 episodes - Fighting Guy's Loudred
Krabby → Kingler - Ash - 62 episodes - Fighting Mandi's Exeggutor
Grotle → Torterra - Ash - 66 episodes - Fighting Team Rocket
Krokorok → Krookodile - Ash - 72 episodes - Fighting Iris's Dragonite
Chikorita → Meganium - Ash - 73 episodes - Protecting Ash from Team Rocket
Aipom → Ambipom - Dawn - 73 episodes - Battling a group of Unown shortly after learning Double Hit
Tepig → Pignite - Ash - 73 episodes - Fighting Shamus's Emboar and Heatmor
Taillow → Swellow - Ash - 76 episodes - Competing against Jessie's Dustox in PokéRinger
Pidgeotto → Pidgeot - Ash - 78 episodes - Protecting Ash from a Fearow and flock of Spearow
Torchic → Combusken -- May - 81 episodes - Fighting wild Breloom
Grovyle → Sceptile -- Ash - 95 episodes - Fighting Team Rocket
Turtwig → Grotle -- Ash - 95 episodes - Fighting Paul's Honchkrow
Poliwhirl → Politoed - Misty - 96 episodes - Took Ash's King's Rock and then transferred between Pokémon Centers
Staravia → Staraptor - Ash -- 105 episodes --Competing against Paul's Honchkrow in PokéRinger
Combusken → Blaziken - May - 109 episodes - Fighting Team Rocket
Eevee → Glaceon - May - 110 episodes - Touching the Ice Rock on Route 217
Pineco → Forretress - Brock - 116 episodes - Protecting wild Pokémon from Team Rocket
Mudkip → Marshstomp - Brock - 123 episodes - Fighting Ash's Grovyle
Chimchar → Monferno - Ash - 129 episodes -After defeating Paul's Ursaring
Squirtle → Wartortle - May - less than 135 episodes - Offscreen during her journey in Johto
Happiny → Chansey - Brock - 152 episodes - Healing other Pokémon
Zubat → Golbat -- Brock -- 159 episodes -- Fighting Team Rocket
Bulbasaur → Ivysaur → Venusaur - May -- less than 196 episodes - Both offscreen during her journey in Johto
Phanpy → Donphan -- Ash -- 198 episodes - Fighting a Team Rocket mecha
Togepi → Togetic - Misty - 269 episodes - Protecting a group of Togepi from Colonel Hansen
Onix → Steelix -- Brock - 446 episodes - Training from Forrest
Cyndaquil → Quilava - Ash - 504 episodes - Fighting a Team Rocket mecha
Main Characters' Pokemon that don't evolve
Iris's Axew - Wants to fully evolve
Dawn's Piplup - Given an Everstone
James's Mime Jr. - Has not evolved despite knowing Mimic
Ash's Squirtle - Doesn't want to evolve; wants to be part of the Squirtle Squad.
Ash's Bulbasaur - Does not want to evolve
Meowth - Believes he cannot evolve; hates Persian
Ash's Pikachu - Does not want to evolve
- Meowth, Psyduck and Croagunk are iconic so generally aren't evolved unless the script writers want them to (like Brock's iconic Happiny which evolved and thus progressing his personal storys). Sometimes the script writers will go out of their way to make a Pokemon, that should evolve, not evolve (like Mime Jr.)
- Buneary doesn't evolve as her cuteness in her un-evolved form gets attention in contests especially when a cute move is used. Dawn has different Pokemon on her team for creating different moods/tones such as her Mamoswine for strength.
- Some Pokemon don't evolve in order to maintain a certain tone. Ash's Corphish would probably much more entertaining for kids who watch Pokemon than a Crawdaunt. This goes for a lot of Pokemon, like Gible, and Ash's Buizel probably didn't evolve because it thought Ash liked it the way it was as he went out of his way to obtain Buizel and the script writers thought that Buizel reflected Ash being a child but determined and strong nonetheless.
- A lot of secondary character's Pokemon don't evolve as they aren't that important/significant in the Anime; that is not to say they can't/won't though.
HOPE I HELPED.