1. Sponges & Cnidarians

2. Objectives Body structure Feeding & digestion Reproduction cycle
Importance of cnidarians

3. Phylum Porifera Sponges Simplest animals, multicellular
No organs or body systems
Asymmetry
Cellular digestion
Feed by filtering water
Do not move
Reproduce sexually and asexually

4. Sponges

6. Glassy sponges

9. Sponge Anatomy Osculum: large opening at top; water exits
Collar Cells (Choanocytes); layer of cells with flagella that move water and digest food
Ectoderm: outer layer
Jellylike Cells (Amebocytes); move inside to supply nutrients, carry away wastes, form sperm and eggs
Pore (Ostia); where water enters
Spikes (Spicules): rigid frame for support

10. Sponges structure

11. Phylum Cnidaria
Cnidarians (Jellyfish, Hydra, Sea Anemone, Coral, Portuguese Man-of-War)
Tentacles with stinging cells (Cnidocytes)
Venom paralyzes fish (prey)
Pull food into the mouth
Food goes into a central cavity
Specialized tissues help them move (swim, flip, shrink, bend)
Symmetry: Radial or Asymmetry
Reproduce
Asexually (budding)
Sexually (both sexes in one animal or separate)

12. Cnidarian Anatomy Body Plans
Polyp (stationary/vase shaped) Medusa (swimming/cup-shaped)
Jellyfish
Portuguese
Man-of-War
Hydra
Coral
Sea Anemone

13. Polyp

14. Medusa

15. Reproduction in cnidarians

17. New vocabularies
Cnidocytes: cnidarians tentacles are armed by stinging cells.
Nematocytes:a capsule that holds a coiled tube like structure containing poison
Gastrovascular gut: A cavity in which digestion occurs & undigested food is ejected through the mouth

18. Comparison between Sponges Cnidarians Body plan Feeding & digestion
Asymmetry
Radial Symmetry
Feeding & digestion
*Filter feeders: Filtering small particles from water by collar cells
*Digestion takes place within jelly like cells called archeocytes.(in each cell):
These cells help in :
1-digestion
2-productio n of eggs & sperms
3-excretion
*Capture prey with tentacles(that are armed with stinging cells called Cnidocytes.
(Each cnidocytes contains thread like tube contain poison called nematocyte)
*Digestion: in gastrovascular cavity
Movement
Sessile (stay or attached to one place)
Sessile or free floating
Response to stimuli
*No nervous system
*Cells react to stimuli by closing their pores
Simple nervous system consists of nerve net.
Repronoduction
*Hermaphrodites:reproduces sexually
*Reproduces asexually by fragmentation,budding or gemmule production
Separate sexes; Medusa reproduces sexually
Polyp reproduces asexually
by budding.

19. Assignment #3: Sponges
Draw a Diagram to show how water travels through a sponge (use arrows)
Answer the following:
How do pores help a sponge feed?
How do collar cells help a sponge feed?
What is the function of the osculum?
Why is a sponge classified as an animal?