A sandy beach is made up of minute grains of sand or crushed shells and rock. Because it is grainy, wind and water reshape a beach every day. Sandy shores are exciting places with life in and underneath the water.

The Intertidal Zone
The intertidal zone is the area exposed between high and low tides. In the intertidal zone, part of the day is spent in open air and the rest of the day is spent covered in ocean water. High tide brings with it nutrients and food. When it goes out, the tide takes with it waste products and disperses eggs and larvae. Because of the shifting sands, organisms living in the intertidal zone on a beach have adapted to these changing conditions. Without the cover of water, many animals simply shut down during low tide. Some of the animals spend most of their life buried under the sand. Others burrow into the sand when the tide is low or when the crashing waves hit the shore. Some of the animals feed on materials that washes ashore. Others filter food from the water. Still others feed on tiny algae and bacteria among the sand grains.

Walking Along a Sandy Shore
Examine the strand line as you walk along a beach. You can run into many interesting things. 

Always wear shoes when you walk along the beach. Besides the many natural items you find as you walk, unfortunately you'll encounter the man made dangers of broken glass, litter, and pollution, too. 

Look for sea stars. Sea stars are a very basic and primitive form of life. If a sea star loses a leg, it will grow back. Obviously, such is not the case with a human being or a mammal. Through thousands of years, mammals have evolved to much more complex systems than starfish. Mammals' limbs are more complex, and have a central nervous system. 

You'll find many sea shells. They are the former homes of snails and other aquatic creatures. Their exoskelton (which means skeleton outside the body) is all that remains of them. Shells are beautiful and fun to collect. 

Clam shells are exoskeltons of living creatures. In parts of the world, such as the eastern coast of the United States, you can dig for clams along the beach and then cook them.

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