AY Honors/Shells - Advanced/Answer Key
1. Have the Shell Honor.
2. Define the term "mollusca" or "mollusk."
The word mollusc is derived from the French mollusque, which originated from the Latin molluscus, meaning thin-shelled, from mollis, soft
The body of a mollusk consists of three sections; a head, with eyes or tentacles; a muscular foot; and a visceral mass housing the organs.
3. Learn the classification terms of mollusks, know the distinguishing characteristics of each, and become acquainted with several species under each class.
There are ten classes of molluscs; eight of the classes have living representatives, the other two classes are known only from fossils. More than 250,000 species of mollusc are recognized and named. Snails (Gastropoda) account for about 80% of living mollusc diversity.
| Class | Major organisms | Extant species | Distribution |
| Caudofoveata | worm-like organisms | 70 | deep ocean |
| Aplacophora | solenogasters, worm-like organisms | 250 | deep ocean |
| Polyplacophora | chitons | 600 | rocky marine shorelines |
| Monoplacophora | limpet-like organisms | 11 | deep ocean |
| Gastropoda | abalone, limpets, conch, nudibranchs, sea hares, sea butterfly, snails, slugs | 150,000& | marine, freshwater, land |
| Cephalopoda | squid, octopus, cuttlefish, nautilus | 786 | marine |
| Bivalvia | clams, oysters, scallops, mussels | 8000 | marine, freshwater |
| Scaphopoda | tusk shells | 350 | marine |
| Rostroconchia † | fossils; probable ancestors of bivalves | extinct | — |
| Helcionelloida † | fossils; snail-like organisms such as Latouchella | extinct | — |
4 Distinguish between univalve and bivalve mollusks from the following considerations:
a. Shell
The terms univalve and bivalve refer to the configuration of the shells of the mollusks. Univalves, such as snails, have shells consisting of one (thus uni-) piece. Bivalves, such as mussels, have shells consisting of two (thus bi-) pieces hinged together.
b. Mollusk body
Univalve bodies could almost be described as folded such that the mouth and anus both appear the the shell's opening. Bivalves on the other hand have flattened bodies.
c. Reproduction
d. Movements
e. Securing food
Bivalves are unique among the molluscs for lacking a radula; they feed by siphoning and filtering large particles from water.
f. Self-preservation
5. Identify from shells or drawings and know the meaning of the following concho logical terms:
a. Valve
b. Apex
c. Aperture
d. Byssus
e. Foot
f. Mantel
g. Operculum
h. Mother of pearl
i. Epidermis
j. Ribs
k. Teeth
l. Concentric lines
m. Canal
n. Spines
o. Whorls
p. Lips
6. Explain the development of a shell. How long do mollusks live?
7. Give some facts about the life of a strombus pugilis (fighting conch) and explain why this shell is so named.
8. Explain the activities of the shipworm.
Adventist Youth Honors Answer Book/Nature/Shipworm
9. What accounts for the distribution of mollusks.
10. Name two mollusks that have no shells.
Slug 
Octopus 
Cuttlefish 
Squid
11. Find answers for the following interesting questions:
a. How are bivalve and univalve animals fastened to their shells?
b. How is shell color controlled?
c. What mollusk has four gills?
d. From what sea animal was India ink formerly made?
e. What mollusk spins a silken thread?
f. What shells were used for money by ancient tribes?
g. What shell is considered sacred by the Tibetans?
h. Purple dye of ancient times came from the secretion of what mollusk?
i. What is the source of pearls? How are they formed?
12. Name six commercial uses for shells.
13. Do one of the following:
a. Personally find and collect 40 species of shells representing the five classifications. List each shell as to the place and date it was found, common name, scientific name, and class.
b. Make a collection of 50 species of shells you have found, received, or purchased representing the five classifications. List each shell collected as follows: if personally found, give the information called for under letter "a" above; if received or purchased, give the name of the person from whom the shell was received, the habitat of the shell, the date of its acquisition, and its common name, scientific name, and class.
References
- ↑ Ponder, Winston F. and Lindberg, David R. (Eds.) (2008) Phylogeny and Evolution of the Mollusca. Berkeley: University of California Press. 481 pp. ISBN 978-0520250925.
