When you are done, try the Mollusks Quiz:
A mollusk is another name for a shellfish. There are three groupings of shellfish. They include:
Shellfish are not all fish and many of them live on land. Not all of them have shells. They are not fish, although many of them live in the water.

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System
Type
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Mollusks
System
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| Muscular-Skeletal | A Mollusk has an outer shell. It has a soft body. It has a muscular foot that it uses for movement. |
| Digestion | A Mollusk has food brought in through a siphon system and then to its mouth. It then goes to a digestive gland and to its intestine. Wastes leave via the anus. |
| Nervous | A Mollusk has no formal nervous system, but has a series of ganglia that conduct impulses. |
| Circulation | A Mollusk has a heart, blood and blood vessels. |
| Respiration | A Mollusk has tubes called siphons that bring water in and out of their bodies so that they can get oxygen and give off carbon dioxide. They have gills that help with this. |
| Reproduction | A Mollusk is either male or female and reproduces sexually with a large organ called a gonad. |
| Excretion | A Mollusk has an excretory system with an anus. It has an organ called the nephridium that gets rid of wastes. |
| Symmetry | A Mollusk has bilateral symmetry. |
| Appearance | A Mollusk has a soft, thick, fleshy body. It can be very small or as big as six feet across. |
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Mollusk Links |
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