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Activity

Clam dissection (or mussel)

Summary: 
Students look at the inside of a real clam (or mussel). They identify major body parts of the clam, and compare them to human anatomy.
Science content (2016 curriculum): 
Biology: Features, Adaptations of Living Things (K, 1, 3, 7)
Biology: Classification of Living Things, Biodiversity (1, 3)
Biology: Sensing, Organ Systems (4, 5, 6)
Science topic (2005 curriculum connection): 
Life Science: Characteristics of Living Things (grade K)
Life Science: Needs of Living Things (grade 1)
Life Science: Animal Growth and Changes (grade 2)
image
Materials: 
  • clam (e.g. savory clam) for each student. Purchase at a shellfish store and store in a fridge in a closed plastic bag for two days before use, so that the animals are dead, but still fresh
  • dissecting tray for each student (a large petri dish works well)
  • penknife or other sharp knife for teachers to open the clams
  • flat toothpick for each student (better than the round, pointy kind)
  • labeled image of a dissected clam for each table group (http://iweb.tntech.edu/mcaprio/whole_no_mantle_L.jpg, archived at http://web.archive.org/web/20070630042552/http://iweb.tntech.edu/mcaprio...)
  • optional: worksheet with a drawing of a clam and human, and the list of parts for each
Procedure: 

Ask students if they think the inside of a clam will look the same as us. (We are both animals, but they are a mollusc and we are a mammal, so we might expect that some parts are the same and some are different).
The clam has a muscle that keeps the shell tightly closed. As the clams are now dead, the muscle may not be as strong, and students may be able to pull it open, while holding the clam over their dissecting dish (water may spill out of the clam). An adult can open shells that are tightly closed by cutting the two adductor muscles with a sharp knife.
Give students a photo of the inside of a clam: http://iweb.tntech.edu/mcaprio/whole_no_mantle_L.jpg, archived at http://web.archive.org/web/20070630042552/http://iweb.tntech.edu/mcaprio...
Ask students to look at the labeled image and to compare it with their own clam, while they wait for everyone’s clam to be opened.
Working as a class, each organ is found from the list on the clam-person-comparison worksheet (see attachment), starting from the bottom. As each organ is read out, students are assisted in finding the real organ in their dissected clam, by comparing their clam to the dissected clam images. They draw a line from the name of the organ in the clam to the appropriate part of the drawing of the clam. The function of each part is discussed. Then students then find the equivalent human organ from a list, and discuss the equivalent function in humans.
1. The clam SHELL protects the clam. It is its shelter. We do not carry our shelter with us.
2. The MANTLE makes the shell. We do not have a mantle, as we do not have a shell.
3. The clam FOOT helps the clam dig into the sand. We move with our FEET too.
4. The clam GILLS take oxygen from the water (like fish). We have LUNGS for taking in oxygen. (Students may need a toothpick to gently lift up the gills to see them properly).
5. One of the clam SIPHONS sucks in water. Tiny food particles in the water get stuck in tiny hairs on the gills. Then the food gets washed towards the clam's mouth inside the body. The water goes back out the other siphon. We eat with our MOUTH. (Students may need to straighten out the siphons with a toothpick to see them properly.)

Note: a mussel has similar parts, but they are arranged a little differently. See http://faculty.orangecoastcollege.edu/mperkins/zoo-review/clam-mussel/cl...

Attached documents: 
Grades tested: 
Gr K
Gr 1
Gr 2
Gr 3
Teacher: 
Carole Murray
Christy Wong
Diane Merchant
Ingrid
Julie Kawaguchi
Kecia Boecking
Mari Matsuo
Teaching site: 
McBride Elementary
ProD for Elementary teachers
Sexsmith Elementary
Weir Elementary
Activity originally developed and delivered: 

Scientist in Residence Program, Vancouver School District with teachers Ms. Kawaguchi and Ms. Merchant.
http://scientistinresidence.ca/
Original lesson plan at http://www.scientistinresidence.ca/pdf/life-science/Discovering%20Life%2...