Evolution

File:Evolution.gif

Ivysaur becomes Venusaur, depicted in Pokémon FireRed and LeafGreen.

During the course of a Pokémon's development, under certain circumstances specific to that Pokémon's species, it may evolve (Japanese: 進化 shinka) into a different Pokémon. This change is not merely physical, however, as Pokémon of a higher evolutionary stage have different (and usually more powerful) base stats than their predecessors, may have different moves that can be learned, and sometimes change their types, though usually at least one of the types of the previous form is preserved. Other statistics, such as nature and EVs, as well as alternate coloration, are preserved.

Evolution families

An evolution family is a group of Pokémon who will all, if bred with Ditto, make a Pokémon egg that will hatch into the same Pokémon, excluding baby Pokémon. This also means that the most basic form has the potential to become any of the rest of the family, although it will only be able to follow one evolutionary path, ultimately.

Stages of evolution

Pokémon can be classed into different evolutionary stages, based on their appearance in their evolution family. All Pokémon fall into one of four groups: baby Pokémon, unevolved Pokémon, first-evolution Pokémon, and second-evolution Pokémon. These groups are also the basis for the TCG's grouping of Baby Pokémon, Basic Pokémon, Stage 1 Pokémon, and Stage 2 Pokémon, respectively.

Due to the fact that no evolution family contains both a baby Pokémon and a second-evolution Pokémon, many regard baby Pokémon as the most basic form, while moving their evolved counterparts one level higher. For example, originally, Pikachu was regarded as an unevolved Pokémon, however, with the release of Pichu in Generation II, many now considered it more on par with Pokémon like Charmeleon, though its TCG classification remained the same.

Two-evolution families

Main article: Pokémon that are part of a three-stage evolutionary line

Perhaps the most well-known types of evolution families are those that feature two separate evolutionary events in the Pokémon's development. Indeed, this type of evolution family is what all of the starter Pokémon in the main series are a part of, including Pikachu. An example of this type of evolution family is below.

Lowest	Trigger	Middle	Trigger	Highest
Dratini	Level 30	Dragonair	Level 55	Dragonite

One-evolution families

Main article: Pokémon that are part of a two-stage evolutionary line

By far the most common type of evolution family, these families are based in a Pokémon that will only ever evolve once in its development. About one third of all Pokémon that would later get a baby form were part of this kind of evolution family before their baby form was revealed. An example of this type of evolution family is below.

Lowest	Trigger	Highest
Rattata	Level 20	Raticate

Pokémon that do not evolve

Main article: List of Pokémon that do not evolve

The least common type of evolution family, of course, is that in which no evolutionary event takes place, meaning that it is made up of only one member. Many of the Pokémon that have no evolutionary event are, of course, legendary Pokémon. However, there are still 42 other Pokémon that do not evolve. Below is a list of all non-legendary Pokémon that do not evolve.

Gen I		Gen II		Gen III		Gen IV
	Farfetch'd		Unown		Sableye		Pachirisu
	Kangaskhan		Girafarig		Mawile		Chatot
	Pinsir		Dunsparce		Plusle		Spiritomb
	Tauros		Qwilfish		Minun		Carnivine
	Lapras		Shuckle		Volbeat		Rotom
	Ditto		Heracross		Illumise
	Aerodactyl		Corsola		Torkoal
			Delibird		Spinda
			Skarmory		Zangoose
			Stantler		Seviper
			Smeargle		Lunatone
			Miltank		Solrock
					Castform
					Kecleon
					Tropius
					Absol
					Relicanth
					Luvdisc

It must be noted that not belonging to an evolutionary family is not an indication of strength overall. Some Pokémon, like Pinsir and Skarmory are comparable to fully evolved Pokémon while others, like Luvdisc and Pachirisu, are more comparable to unevolved Pokémon. Often this indicates a Pokémon's possibility to be eligible for future new evolutions or pre-evolutions.

Branch evolution families

Main article: List of Pokémon with branched evolutions

Several families, while also one- and two-evolution families, are also branch evolution families. What this means is that there is a split in the evolutionary line at some point so that even though two Pokémon of the same species evolve the same amount of times, they can become one of two or more entirely different creatures. Eevee is the best-known example of this, evolving seven different ways depending on the method used. An example of this type of evolution family is below.

Lowest	Trigger	Middle	Trigger	Highest
Poliwag	Level 25	Poliwhirl	Water Stone	Poliwrath
			Trade holding King's Rock	Politoed

Advantages

A major difference between the final forms of an evolution family with a branch in evolution is in the way that their base stats line up. For example, Kirlia evolves into both Gardevoir and Gallade, which both have 518 total base stats. However, Gallade's base stat in Attack is 125 and its base stat in Special Attack is 65. The reverse is true for Gardevoir, whose Special Attack is 125 and whose Attack is 65. This is true of many opposing evolutions, with one focusing in one specific stat, the other focusing in a separate stat, and both having the same total stats. This is especially obvious in the Eeveelutions, who each have exactly the same base stats, though organized differently.

A listing of the stat focuses is below.

Basic form		Evolutions		Types		Difference
	Oddish		Vileplume	Grass	Poison	Special Attack is 100, Special Defense is 90
			Bellossom	Grass		Special Defense is 100, Special Attack is 90
	Poliwag		Poliwrath	Water	Fighting	Attack is 20 higher, Defense is 10 higher
			Politoed	Water		Special Defense is 20 higher, Special Attack is 10 higher
	Slowpoke		Slowbro	Water	Psychic	Defense is 110, Special Defense is 80
			Slowking	Water	Psychic	Special Defense is 110, Defense is 80
	Eevee		Vaporeon	Water		Highest stat is HP
			Jolteon	Electric		Highest stat is Speed
			Flareon	Fire		Highest stat is Attack
			Espeon	Psychic		Highest stat is Special Attack
			Umbreon	Dark		Highest stat is Special Defense
			Leafeon	Grass		Highest stat is Defense
			Glaceon	Ice		Highest stat is Special Attack
	Tyrogue		Hitmonlee	Fighting		Large difference between Attack and Defense
			Hitmonchan	Fighting		Speed lower than Defense, Attack and Defense more equal
			Hitmontop	Fighting		Attack and Defense equal, Speed at minimum
	Wurmple		Beautifly	Bug	Flying	Attack and Special Attack higher than Defense and Special Defense
			Dustox	Bug	Poison	Defense and Special Defense higher than Attack and Special Attack
	Ralts		Gardevoir	Psychic		Special Attack is 125, Attack is 65
			Gallade	Psychic	Fighting	Attack is 125, Special Attack is 65
	Snorunt		Glalie	Ice		All stats are 80
			Froslass	Ice	Ghost	HP, Defense, Special Defense each 10 lower, Speed 30 higher
	Clamperl		Huntail	Water		Attack is 104, Special Attack is 94
			Gorebyss	Water		Attack is 84, Special Attack is 114
	Burmy		Wormadam	Bug	Grass	Special Attack and Special Defense higher by 10
			Wormadam	Bug	Ground	Attack and Defense higher by 10
			Wormadam	Bug	Steel	Equal Special & Normal stats
			Mothim	Bug	Flying	Lower Defenses but higher HP, Attacks, and Speed

Methods of evolution

Main article: Methods of evolution

The various triggers for a Pokémon's evolution are almost as varied as the Pokémon themselves. The most common of them is evolution by leveling up at or above a certain level. Other methods include leveling up when happiness has reached a high level, trading the Pokémon, trading the Pokémon holding an item, leveling up holding an item, or even using an evolutionary stone on it. Additionally, holding an Everstone prevents a Pokémon from evolving.

Most commonly, Pokémon that can evolve into more than one Pokémon will have the ways in which the evolution is activated being slightly similar, such as having both be by evolutionary stone or by holding an item and trading. Closely-related Pokémon, such as Nidoran♀ and Nidoran♂, will also have very similar, if not identical, evolution methods.

In the anime

In the anime, evolution happens in much the same way as it does in the games; though level-based evolution nor trade-based evolutions do not occur using those methods, there are similarities in the way they come about. For example, Misty's Poliwhirl evolved into Politoed because it found Ash's King's Rock and was holding it when Misty sent it out, while in the games it is required that Poliwhirl be traded while holding the King's Rock for the evolution to take place. When a Beedrill attacked Ash's Metapod, it caused a crack to appear on its shell, which Butterfree came out of it. The other aspect about the anime is the evolving is very different. For example, when Metapod evolve they leave their shells behind. However, starting from the Advanced Generation series it's changed (eg. Cascoon just turn into Dustox not leaving anything behind).

Additionally, a difference can be noted in the fact that Pokémon evolve during a battle, as opposed to after it. There are also several instances of an evolutionary trigger being incorrect, such as March of the Exeggutor Squad where several Exeggcute evolve into Exeggutor without the aid of a Leaf Stone. Pokémon may also evolve when they are needed to, for an extra boost of power, instead of after a set amount of training, such as when Ash's Charmeleon evolved into Charizard. In addition, Pokémon can sometimes choose not to evolve, even if they evolve by a 'natural' method such as leveling up. It appears that evolution has emotional implications for Pokémon - some Pokémon, such as Team Rocket's Meowth, dislike their evolved forms, while others such as Ash's Pikachu simply want to prove they can be powerful without evolving. Conversely, when Pokémon do evolve, this can often be linked with an experience that causes them to mature emotionally or deal with an emotional issue, such as when the Poochyena in A Bite to Remember evolved, or the Paras in The Problem With Paras. Poochyena, for some reason, had an aversion to using the move Bite, while Paras was extremely timid and weak in battle. Both of them evolved shortly after overcoming these issues.

For a list of all evolutions that Pokémon belonging to the main cast have undergone, see List of anime Pokémon by evolution.

In the TCG

Main article: Evolution (TCG)

Evolution in the TCG functions similarly in many aspects to that of the games, however, there is no different requirement that needs to be met depending on the Pokémon species to be evolved to move on to the next stage.

There are four different stages of evolution in the TCG, Baby Pokémon, Basic Pokémon, Stage 1 Pokémon, and Stage 2 Pokémon. Of these, only Baby and Basic Pokémon may be placed onto the Bench during the setup phase and during play; Stage 1 and Stage 2 Pokémon are considered to be evolution cards and therefore unable to be played except on top of their corresponding pre-evolved forms. The stage of evolution is indicated in a conspicuous place on each and every Pokémon card, though the placement differs among the four generations of cards.

Within the deck and discard pile, only Stage 1 and Stage 2 cards are considered to be "evolution cards" for the purpose of a Trainer card or Pokémon Power which allows them to be searched for. In play, a Basic Pokémon card can be considered an evolution card if it is evolved from its Baby stage.

In relation to the real world

Evolution in Pokémon, for most species, is more akin to metamorphosis than to actual evolution. The Pokémon whose evolution is closest to the real-world definition of evolution is Eevee, whose cellular structure changes due to its environment. However, even Eevee's evolution is more like metamorphosis, because evolution happens to a population rather than to individuals.

See also

• List of Pokémon by evolution family
• List of Pokémon with cross-generational evolutions