Graduation Requirements
Science Biological
Equipment/Materials Needed

No special equipment or materials are needed

The three large classes of Mollusk are Gastropods (snails, slugs), Bivalves (clams, scallops), Cephalopods(squid, octopus)

Badge Completion Requirements


This class comprises snails and slugs from saltwater, from freshwater, and from the land.

Gastropod, any member of more than 65,000  species belonging to the class Gastropoda, the largest group in the phylum Mollusca. The class is made up of the snails, which have a shell into which the animal can generally withdraw, and the slugs, which are snails whose shells have been reduced to an internal fragment or completely lost in the course of evolution.


Snails have a basic body design:

snail image

Of the more than 65,000 species, about 30,000 are marine, 5,000 live in fresh water, and 30,000 live on land. In general, oceanic gastropods are most diverse in the number of species and in variety of shell structures in tropical waters; several hundred species (each represented by a small number of individuals) can be found in a single coral reef habitat. Most gastropods are marine as the one below:

Freshwater snails are common in ponds, streams, marshes, and lakes. Usually, only a few species are found at one place, but each species will have a rather wide range. Most species are common and feed on algae or dead plant matter.

Please review the following:

Land snails are very successfully, terrestrial dwellers. When actively moving, they continuously lose water. During periods when water is unavailable, they retreat into their shells and remain inactive until conditions improve.

Please review the following material provided by



Please define the following words in your presentation




Explain medical concerns regarding snails

Plan an expedition searching for gastropods 

Collect and identify three different species of gastropods


Please develop and submit a presentation demonstrating your understanding of Gastropoda. Please include the above prompts in your presentation.   


Bivalves include clams, scallops, oysters, and mussels. 

As their name implies, they have two parts of their shell, which can open and close. 

Bivalves live in both marine and freshwater habitats.

Most bivalves have a pair of large gills that enable them to extract oxygen from the water (to breathe) and to capture food.

Internal Anatomy of a Bivalve



clam anatomy

Gross Anatomy of a Bivalve Shell

gross anatomy

Scallop movement-Unlike other bivalves such as mussels and clams, most scallops are free-swimming. They swim by clapping their shells quickly using their highly developed adductor muscle, forcing a jet of water past the shell hinge, propelling the scallop forward. 

Clams and mussels use the foot to move


Please review the following:


Explain the formation of a pearl

Do only Bivalves form pearls?  Explain

Discuss the feeding mechanism for Bivalves

Compare and contrast Snails and Bivalves

Explain the environment where Bivalves live.

Collect a sample of Bivalves shells

Explain the invasion of Zebra Mussels in the United States 


Please develop and submit a presentation demonstrating your understanding of Bivalves. Please include the above prompts in your presentation.