Methods of evolution
A natural part of a Pokémon's life is Evolution and most will benefit from it, unfortunatly the process of evolution can differ from species to species, making it slightly harder for a Pokémon to get there.
These are the current methods of evolution.
Evolve by Level
Most evolution happens by a Pokémon hitting a certain Level, a Pokémon earns levels by gaining Experience Points from a battle.
A Rare Candy can make a Pokémon instantly gain a level, potentially getting the Pokémon one step closer to evolving.
Evolve by Element Stone
Some Pokémon will only evolve after being exposed to an Element Stone.
If a Pokémon's next stage requires the use of a stone, then it can be applied at any time, this causes instant evolution.
However, once exposed to an element stone, a Pokémon can no longer learn any more Attacks by leveling up.
Example: Nidorino evolves into Nidoking by being exposed to a Moon Stone.
Evolve through Trading
Some species can only be gotten by being traded to another trainer, as soon as a Pokémon is transfered the evolution process immediately begins.
Evolve through Happiness
There comes a time when the only way for a Pokémon to evolve is through making it especially happy, this is usually true for Baby Pokémon such as Cleffa.
Once a Pokémon's hidden happiness stat hit a certain level, it would immediately start to evolve.
See: Raising Happiness
Other Methods
A single Pokémon makes use of another hidden stat, the beauty stat, that Pokémon is Feebas. After it's beauty stat reaches a certain point and the Pokémon gains an additional level, it will evolve into a Milotic.
Tyrogue has an odd three-way branched evolution depending on it's stats when it reaches level 20.
- Evolves into Hitmonchan if defence is higher than attack.
- Evolves into Hitmonlee if attack is higher than defence.
- Evolves into Hitmontop if defence is equal to attack.
Wurmple's evolution into either Cascoon or Silcoon could be based on a variety of factors, but it is seemingly random, dictated from when the Wurmple is caught.
The method of recieving a Shedinja is perhaps the oddest form of evolution, it can scarecly be called an evolution. Once a Nincada reaches level 20 it will evolve into a Ninjask, however, if the player has a free party slot at the time, a Shedinja will fill that slot at evolution.