This fosters a rich growth of plankton, the base of the marine food web and a source of food for near-shore marine life. Most important, plants and animals, through natural selection, have developed adaptations that allow them to live in this difficult neighborhood. These special adaptations are quite varied. They may consist of shells that close like trap doors when the tide goes out. Or clinging feet with suction cups, or muscles that grip the rocks.
Some animals can fold themselves up or disappear down a long tube, to await the return of high tide.
Others literally tie themselves to the rocks with secreted fibers, to resist the force of moving water. Rubber necks and flexible stalks allow some intertidal residents to bend with the waves. Many have a tough skin, or impregnable armor to keep them moist and cool while exposed to air.