Comparing and Contrasting Different Classes of Mollusks
1. List four members of the class Gastropoda and one feature that is common to most
members of this class.
Snails, slugs, abalones, sea butterflies, sea hares, and nudibranchs
2. From what is the class name Bivalvia derived?
Bi (meaning two) and valve (meaning shell) – These animals have two shells.
3. List three members of the class Bivalvia. Scallops, oysters, and clams
4. List three members of the class Cephalopoda and one feature that is common to most
members of this class.
Octopi, squid, cuttlefish, nautiluses – All members of this class have their foot
attached directly to their head (tentacles to head).
5. Describe how gastropods, cephalopods, and bivalves each use unique ways to protect
themselves from predators.
Shell gastropods coil up in their shells for protection, while other sea gastropods use
ink or poisons to ward off predators. Land slugs avoid predators moving mostly at
night and hiding under rocks during the day.
Bivalves use their two shells for hiding and protection while clams will also burrow
deep in sand or mud.
Cephalopods use ink secretions in the water to distract predators while they take off.
Many octopi also have the ability to change to the colour of their surroundings in
order to camouflage themselves.
6. Describe the process of pearl formation.
A sand grain or small pebble gets caught between the mantle and the shell of an
oyster. The mantle covers the particle with secretions of a substance called nacre.
After years of buildup the particle becomes a pearl.