Class Bivalvia and Bivalve Shell Quiz

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Questions and Answers

What is the function of the hinge ligament in bivalve shells?

To filter feed using respiratory currents

To attach the bivalve to a substrate

To secrete nacre around foreign material

To draw the valves together using adductor muscles (correct)

Where is the umbo located in a bivalve shell?

At the dorsal midline of the shell

As the oldest part of the shell (correct)

At the hinge ligament

Around the foreign material forming pearls

Where are gland cells located that secrete mucus to entangle particles in bivalves?

On the foot

On the labial palps (correct)

On the ctenidia

On the mantle

How do scallops and file shells move?

By creating a jet propulsion by clapping their valves Signup and view all the answers

What is responsible for producing pearls in bivalves?

An irritant lodged between the shell and mantle Signup and view all the answers

What is the function of the crystalline style in bivalve digestion?

To secrete digestive enzymes Signup and view all the answers

In bivalves, how is food directed into the mouth for ingestion?

By sliding down food grooves at the edge of gills Signup and view all the answers

Where does fertilization usually occur in bivalves?

In the suprabranchial chamber Signup and view all the answers

What is the role of nephridial tubules in bivalve circulation?

Regulation of water balance Signup and view all the answers

What is the purpose of the three-chambered heart in bivalves?

To pump blood to the gills Signup and view all the answers

How do glochidium larvae complete their development?

By attaching to gills of passing fish Signup and view all the answers

Where do juveniles of glochidium larvae usually detach and begin independent life?

On the substrate after encysting on a host Signup and view all the answers

Which type of larval stage is hatched with the beginnings of a foot, shell, and mantle in many gastropods and bivalves?

Veliger larva Signup and view all the answers

What class has over 70,000 living and more than 15,000 fossil species, including marine snails, limpets, slugs, whelks, and sea slugs?

Class Gastropoda Signup and view all the answers

What is the characteristic feature of gastropod shells in terms of coiling formation?

Dextral (right-sided) Signup and view all the answers

Which type of larvae do cephalopods, some freshwater bivalves, and snails lack?

Veliger larva Signup and view all the answers

What is the smallest and oldest part of the whorl in a gastropod shell?

Apex Signup and view all the answers

What is the function of the operculum in many snails in relation to the shell?

Covering shell aperture (entry) Signup and view all the answers

Study Notes

Bivalve Anatomy and Functions

The hinge ligament connects the two halves of a bivalve shell, allowing it to open and close efficiently.
The umbo is the rounded, elevated area on the shell's dorsal side, often the oldest part of the shell.
Gland cells that secrete mucus are located in the mantle, allowing for the entrapment of particles for feeding.

Movement and Feeding

Scallops and file shells can swim by rapidly opening and closing their shells to expel water.
Pearls are produced by the secretion of nacre by the mantle tissue in response to irritants.
The crystalline style aids in digestion by rotating within the stomach, mixing food with digestive enzymes.

Reproductive and Developmental Processes

In bivalves, food is directed into the mouth through ciliary action and water currents created by gills.
Fertilization typically occurs in the water column or within the gills of the female bivalve.
Nephridial tubules filter waste from the blood, playing a crucial role in the circulatory system.

Heart and Lifecycle

The three-chambered heart pumps blood, facilitating circulation and nutrient distribution throughout the body.
Glochidium larvae undergo a parasitic stage, often attaching to fish gills to complete their development.
Juveniles of glochidium larvae detach from the host fish and begin independent life in the aquatic environment.

Gastropod and Cephalopod Characteristics

The larval stage that hatches with initial structures like a foot, shell, and mantle is known as a veliger.
Gastropoda class includes over 70,000 living species and around 15,000 fossil species, encompassing a variety of marine organisms.
Gastropod shells display a unique coiling pattern, often resulting in asymmetrical shapes.
Cephalopods, some freshwater bivalves, and certain snails do not possess a trochophore larval stage.

Shell Structure and Functions

The protoconch is the smallest and oldest part of the whorl in a gastropod shell, providing the initial shape.
The operculum functions as a protective cover for many snails, sealing the shell's opening when the animal retreats inside.