Depending on the evolution some pokemon have differences at how they evolve plus depending on the generation that the pokemon evolves in okay?
Say like:
Weedle - Kakuna - Beedrill = This is Weedle's evolution line as seen from your screen
Nidoran(Male) - Nidorino - Nidoking - as seen the only one your missing is Nidoking you'll need a moon stone for him to evolve into that pokemon from your Nidorino...
Nincada - Ninjack are the evolution line if you had a extra space you'd also have a Shieldnija which is also part of it's evolution so you know...
If you need help with your game do feel free to let us know okay?