It was rather annoying to download the 60MB update outside but Gen2 Pokemons in the Pokemon Go game is out.
With more than 80 new Pokemons out, and some of the original pokemon can be evolved.
Sadly, there are items you need to get for some of these new Pokemons to be evolved.
Metal Coal for
Onyx to become Steelix
Scyther to be Scizor
Dragon Scale for Seadra to become Kingdra
Slowpoke to be SlowKing
Polywhirl to be Polytoed
Sun Stone for Gloom to be Bellosom
So you can see, not only do you need candies, there are items needed for evolution.
-- Robin Low