1. Sponges & Cnidarian
Chapter 35

2. Sponges Invertebrates - animals without back bones.
Simplest of the multicellular animals.
No organ system.
Kingdom: animalia
Phylum: porifera

3. Movement Holdfast - root-like - attach the sponge to rocks.
Adult sponges are sessile - unable to move.

4. Structure : Skeleton Spongin
Spicule – hard, spike-like, particles of calcium carbonate of silicon dioxide that make up a sponges skeleton

5. Structure Collar cells-create a current of water through the sponge.
Thousands of pores let water flow through it continually.
Water exits through the osculum – opening at the top of the sponge.

6. Filter Feeding Obtain nourishment and oxygen from this water.
Engulfed by collar cells and passed to amebocytes which distribute the nutrients to the rest of the body.

7. Reproduction
Budding
Gemmules
Regeneration
Sexual reproduction

8. Sexual Reproduction Sperm released Egg is fertilized
Larva form and leave the sponge.
Larva settles and attaches to an object.
Larva grows into an adult sponge.

10. Examples of cnidarians
Jellyfish
Sea anemones
Coral animals

11. Characteristics of Cnidarian
Invertebrates
Radial symmetry
Tentacles with stinging cells.

12. The two different forms of a Cnidarian body
Bell shaped
Specialized for swimming
Vase shaped
Sessile existence

13. Movement Most cnidarians are slow-moving or sessile
Found on shallow ocean floors, the bottom of ponds or drifting about in water currents.

14. Characteristics Gastrovascular cavity center of the body Hollow gut
One opening surrounded by tentacles

15. Feeding and Defense
Cnidocytes – cells found on tentacles used for defense & capturing prey.
Nematocyst – organelle in cnidocyte which can eject a filament with poison.