Q:

How are sand dollars made?

A:

Quick Answer

Sand dollars are the fused calcium-based shells of a type of sea urchin. These sea urchins are burrowers that feed on tiny organisms in ocean sediment. Their burrowing lifestyle means their spines must be very short, and their bodies are flattened and slightly elongated to enable them to move through sediment more easily.

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Full Answer

The sand dollars found on beaches are generally the hollowed and dried skeletons of the sea urchins that grew them, and each of their features corresponds to missing parts of the whole. The short spines, which are not very useful for defense, are used for locomotion instead. Sand dollar skeletons bear five grooves that somewhat resemble flower petals. These grooves hold double rows of pores the sea urchins use to breathe. They also hold tube feet that are also used for respiration, not for locomotion as with many other echinoderms like sea stars. Their shells have a small hole in the center bottom where their mouth is located. Food in the sediment around them is coated in mucus and moved toward the mouth via the spines and other structures. The urchins have internal strong jaws that grind grains of sand and extract any organic matter before excreting the sand through the tops of their shells.

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Related Questions

  • Q:

    What do sand dollars eat?

    A:

    Sand dollars eat tiny bits of organic material they find on the sea floor. Sand dollars are echinoderms, which means they have spines. They get the name "sand dollar" because their skeletons look like large coins when they wash up on the beach.

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  • Q:

    What are some fun facts about sand dollars?

    A:

    One fun fact about sand dollars is that these animals are closely related to sea urchins. In addition, the white or off-white sand dollar skeletons found on beaches are called "tests," and their five-jawed mouths are at the center of the star-shaped markings on the tests.

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  • Q:

    How do you bleach sand dollars?

    A:

    Sand dollars can be bleached white by simply using a common household bleach and fresh water. Placing them under the sun for a time will also help make the sand dollars whiter naturally.

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  • Q:

    What are some characteristics of sand dollars?

    A:

    Live sand dollars range in color from gray to purple to deep red, and one side of the body is lighter than the other. They vary in size and are flattened discs resembling sea urchins. Sand dollars lie flat when in the water and stand vertically when it comes time to eat.

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