[flukus]

There are a few effects but we don't know what is important and what isn't.

The moon stabilizes the earths rotation (due to orbital mechanics I don't understand), that's probably important for complex life.

Tides are probably important because they help mix up all the elements. Tidal pools also may have been critical for abiogenesis.

The creation of the moon be a huge planetoid hitting us may be responsible for plate tectonics that provide enough volcanism.