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 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 clean sand dollars?

    A:

    Clean sand dollars by ensuring the organism is dead, rinsing it until the water runs clear, soaking it in chlorine bleach and drying it in the sun. Use white glue, diluted with water, to preserve the sand dollar.

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  • 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:

    Where do sand dollars come from?

    A:

    The sand dollars found on beaches are the skeleton, or test, left behind by living sand dollars. Sand dollars live in the sands of shallow waters, where they burrow into the ground for food.

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