Phylum Porifera

Review Questions

Mesohyl contains:

  1. a polysaccharide gel and dead cells.
  2. a collagen-like gel and suspended cells for various functions.
  3. spicules composed of silica or calcium carbonate.
  4. multiple pores.

Hint:

B

The large central opening in the parazoan body is called the:

  1. gemmule.
  2. spicule.
  3. ostia.
  4. osculum.

Hint:

D

Most sponge body plans are slight variations on a simple tube-within-a-tube design. Which of the following is a key limitation of sponge body plans?

  1. Sponges lack the specialized cell types needed to produce more complex body plans.
  2. The reliance on osmosis/diffusion requires a design that maximizes the surface area to volume ratio of the sponge.
  3. Choanocytes must be protected from the hostile exterior environment.
  4. Spongin cannot support heavy bodies.

Hint:

B