"Tides mean that organisms that live in the tidal zone must be adapted both to an above water and underwater environment, as well as be able to withstand waves that hit them every time the tide goes in or out. Some of these adaptations are structural, like barnacles being able to glue themselves to rocks. Others are behavioural, like animals that burrow in mud to protect themselves from the waves or mussels that clamp themselves closed whenever they are in the air to keep from losing water."
-hope this helps :)
