Intertidal zone
The intertidal zone is the area that is above water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 at low tide and under water at high tide
High Tide
High Tide was a band formed in 1969 by Tony Hill , Simon House , Peter Pavli and Roger Hadden .-History:...

 (in other words, the area between tide marks). This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral. The well known area also includes steep rocky cliff
In geography and geology, a cliff is a significant vertical, or near vertical, rock exposure. Cliffs are formed as erosion landforms due to the processes of erosion and weathering that produce them. Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually...

s, sandy beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...

es, or wetlands (e.g., vast mudflat
Mudflats or mud flats, also known as tidal flats, are coastal wetlands that form when mud is deposited by tides or rivers. They are found in sheltered areas such as bays, bayous, lagoons, and estuaries. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of...

s). The area can be a narrow strip, as in Pacific islands that have only a narrow tidal range, or can include many metres of shoreline where shallow beach slopes interact with high tidal excursion.

In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

s in the intertidal zone are adapted to an environment of harsh extremes.