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Kingdom, phylum, class |
Animalia, Mollusca, Bivalvia/Pelecypoda |
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Why are they called bivalves? |
Bi means 2, valve means shell |
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What are siphons and what is their purpose? |
They are filters through which water is sucked through. This allows only the food particles to enter the clam. |
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Adults are usually sessile, but the larva or ______________ is free swimming. |
Trocophore |
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Body organs make up the ___________ mass. |
Visceral |
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What is the oldest part of a clam’s shell called and how can it be located? |
It is the Umbo, and it is the coiled up hump like structure with the tight rings. |
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What do the rings on the clam’s shell indicate? |
They indicate how old the clam is; the more rings the older the clam. |
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Name the clam’s siphons |
Excurrent and Incurrent |
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What holds the two shells together? |
Hinge Ligaments |
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What muscles open and close the clam? |
Adductor |
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Describe the inside lining of the shell. |
Called the nacre, soft and smooth and protects the shell. |
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What is the function of the tooth-like projections at the dorsal edge of the clam’s valves? |
These microscopic teeth help make sure that the valves align properly while closing. To make sure that the shells form a tight seal of protection. |
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Where is the mantle located in the clam? What is its function? |
It is located midway on the anterior surface of the shell. It can be seen as the slight soft edge of the shell where the two halves open. It secretes the shell, also respiratory organ. |
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Describe the clam’s foot. |
It is wedge/axe shaped to help it dig. |
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What is the mantle cavity? |
The large space found between the two lobes of mantle. Water flows through this space and the food and visceral mass are located in this cavity. |
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How do clams breathe? |
Clams use two pairs of feathery gills for respiration (gas exchange), as oxygen diffuses into the gills. |
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What helps direct water over the gills? |
Cilia on gills |
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Where are the palps found and what is their function? |
A pair of labial palps are located at the anterior end of each set of gills. They direct the trapped food toward the mouth. |
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Describe the movement of food from the current siphon through the digestive system of the clam. |
Plankton > Incurrent siphon > Mucous on gills > cilia toward labial palps > Labial palps > Mouth > Stomach > Intestine > Anus > Excurrent Siphon. |
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Where is the clam’s heart located? |
The pericardial area, this is the dorsal surface that the intestine passes through. |
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Why are clams referred to as "filter feeders"? |
They filter plankton out of the water and trap it and direct it to their digestive tracts. |
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What are the parts of the clam’s nervous system? |
They don’t have a formal nervous system but they do have ganglia which conduct nervous impulses, (they also have nerve cords). |
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Miscellaneous: |
Open circulatory system, Indirect Development, Marine=external fertilization Freshwater=Internal fertilization, Invertebrates, Protostomes, No cephalization |
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