system
Given the following post, respond as if you're commenting on Reddit:
human
[Pokémon] How do Golem and Gengar evolve in the wild?

Also Pokémon like Steelix and Scizor who require items.
gpt
Trading seems to involve a data transfer from poke ball to poke ball so it could be that Gen gar and Golem weren't discovered until that form of trading was invented. The energy transfer could effect the Pokemon biology enough to spur an Evolution.