Creatures that live in the intertidal zone have adapted to be able to cope with drying out when the tide is low. It may be the case that without a moon and no tides creatures might never have needed to have adapted in this way and have made that transition to land so there may never have been any terrestrial animals!

Also, lots of marine animals have body clocks that synchronise with the lunar cycle. The clocks tell them when to feed and when to rest but most importantly they often tell them when to breed. In the sea synchronised mass spawning is very common. This is when all the animals release their eggs and sperm at the same time in the same location to try and maximise the chance of fertilisation. Without the important moon to set these clocks synchronised spawning might not be possible.

It’s also possible that other 28 day cycles, such as the menstrual cycle, might originate from lunar cycles in our evolutionary past so should we have evolved as far as being on land we might reproduce in a very different way too.