Phylum Porifera

Phylum Porifera
Parti. Reproduction. Study the stages of sexual reproduction in sponges. Place the letter of the
stage next to its description below.
__ 1. Free-swimming larva develops.
__ 2. Sperm cell unites with a mature egg cell.
__ 3. Larva develops into spongocoel.
__ 4. Sperm cell enters another sponge through a pore.
__ 5. Larva develops into a new sponge.
__ 6. Sperm cells are released by one sponge.
Part II. Multiple Choice. Select the best answer for each question below.
7. Adult sponges are sessile, which means that they
(a) have no gastrula stage.
(b) use a jellylike substance for body support,
(c) attach to a surface and do not move, (d) produce both eggs and sperm.
8. Collar cells perform all of the following functions except
(a) pumping water into the interior of the sponge.
(b) engulfing and digesting food that is filtered from the water.
(c) passing nutrients to the amebocytes.
(d) distributing nutrients throughout the rest of the body.
9. Sponges eliminate carbon dioxide and cellular wastes by
(a) allowing them to diffuse into the water that passes through the sponge.
(b) excreting them into the surrounding water through pores in the body wall.
(c) transporting them to an excretory organ that empties into the osculum.
(d) converting them into usable carbohydrates.
10. After a sponge egg is fertilized, it develops into a(n)
(a) external bud.
(b) gemmule.
(c) larva. (d) gastrula.
11. A sponge is classified as a(n)
(a) protist.
(b) plant.
(c) fungus.
(d) animal.
(e) bacteria.
12. Sponges are
(a) autotrophs. (b) decomposers, (c) filter feeders, (d) scavengers, (e) predators