| A | B |
|---|
| Sponges | Aquatic animals that make up the phylum Porifera. |
| Sessile | Does not move. |
| Collar cells | Cells that draw water into the sponge through numerous pores that penetrate the body wall. |
| Osculum | The opening at the top of the sponge. |
| Spongin | A simple skeleton made of protein fibers. |
| Spicules | Tiny, hard particles of calcium carbonate or silicon dioxide that are often shaped like spikes. |
| Filter Feeding | Obtaining food by screening food out of the water that the collar cells pump through the body. |
| Amebocytes | Cells that take the nutrients from food in the interior of the sponge to body wall. |
| Gemmules | Internal buds formed by freshwater sponges during droughts and cold weather. |
| Regeneration | The ability to regrow missing parts. |
| Polyp | The vase-shaped form of a cnidarian. |
| Medusa | The bell-shaped form of a cnidarian. |
| Epidermis | Outer layer of cells. |
| Gastrodermis | The inner layer of cells that deals with digestion. |
| Gastrovascular cavity | A hollow gut where digestion occurs. |
| Tentacles | Numerous flexible extensions. |
| Cnidocytes | Specialized cells used for defense and capturing prey. |
| Nematocyst | A stinging organelle in the cnidocytes of cnidarians. |
| Nerve Net | The nervous system in cnidarians consisting of a diffuse web of interconnected nerve cells. |
| Planula | A ciliated larva. |
| Coral Reef | A rocklike formation in warm, shallow seas composed of the skeletons of corals. |
| Colloblasts | A cell on the tentacles of a ctenophore that secretes a sticky substance that binds to the organisms prey. |
| Apical Organ | An organ that enables a ctenophore to sense its orientation in the water. |
| Bioluminescence | Production of light. |
