Billion Oyster Project

Exoskeletons, Shells & Endoskeletons Lab


Teacher-Authored Lessons



Class Periods




Subject Areas



Explore anatomy in form and function while exploring NY Harbor Populations! Think about the advantages and disadvantages between shells, exoskeletons and endoskeletons.


  • Students dissect organisms in order to form observations and inferences about exoskeletons, endoskeletons, and shells.

  • Students identify similarities and differences between exoskeletons, endoskeletons and shells (the hard parts).

  • Students understand that exoskeletons, endoskeletons and shells have advantages and disadvantages.

Materials and Resources


  • Clam/oyster shucker or screwdriver
  • small skewers or toothpicks
  • tweezers
  • dissection trays
  • shrimp with head and tails on, mollusks, whole smoked sardines with head on (all dissection specimens purchased from supermarket),
  • magnifying glasses or hand lens
  • microscope and slides (optional)

Before you get started

Tips for Teachers

Give kids expectations about their sketches. Encourage labeling.

Give kids expectations about the dissection process, but plan on having an extra specimen in case the students break the organism down to a "mash of flesh and parts". Talk about why mushing it all up is not productive.
Take your time and let the kids have time too. Debriefing is important.


Prepare groups to maximize student engagement.

Prepare trays and kits that include all supplies for each group (except the organisms-- keep them in the fridge until ready to use!)


Students will have so many questions about the NY Harbor Populations they encounter at the ORS. This lesson began when students were asking, "what is an exoskeleton?" And, "Does the shrimp have a shell?"

Instruction Plan


What are some examples of hard parts on organisms? Ask students to make lists of all the organisms they can name that have either exoskeletons, endoskeletons, shells. You may define endoskeleton as “internal skeleton”.


Explain the class procedure. 3 stations: Shell, Exoskeleton, Endoskeleton. Each group will rotate through the three stations. At each station, read the info card and then dissect an organism. Also see examples of these “hard parts” from additional organisms. Students complete the graphic organizer to record observations and inferences about advantages and disadvantages of the various hard parts. As expertise and time permits, you may have students study tissue under magnification.


Students use the info sheets and teacher conferencing during the dissection to clarify understanding that shells are not living, they are mineral and can grow on the edge as the mantle produces more calcium carbonate, that exoskeletons are made from secretions of chitin from skin and cannot grow, and that bones are made up of cells and therefore can grow from the middle.


how might this thing you noticed provide advantages, or expand the possibilities for this animal? How might it provide disadvantages, or limit the possibilities for this animal? If that feels abstract, maybe frame it as: what can a crab do that an oyster can't? What can an oyster do that a crab can't? And then perhaps, how could you design a better oyster shell / crab exoskeleton in a way that would give an advantage to the crab/oyster or let it do something more effectively?


Exit Slip

Write a paragraph comparing and contrasting 2 out of 3 of the “hard parts” we studied. Include specific details from our lab and discussion.

Use your lab sheet for evidence.


NGSS - Cross-Cutting Concepts

  • Structure and Function

    • Structures can be designed to serve particular functions.
    • Structures can be designed to serve particular functions by taking into account properties of different materials, and how materials can be shaped and used.