1. Sponges Cnidarians Ctenophores
Parazoa and Radiata
Sponges
Cnidarians
Ctenophores

2. Phylum Porifera: The Sponges

3. General Information
Mainly marine organisms; evolved from choanoflagellates
May have algae or bacteria that give them color
Larva are flagellated, adults considered sessile
Many disease-fighting compounds
holdfast

4. Tube Sponges
Encrusting Sponges

5. Characteristics Can reproduce sexually or asexually
Gas exchange and excretion - diffusion at individual cells
Supported by skeletal fibers:
spicules or spongin
Simple animals made of few specialized cells; NO tissues
Asymmetrical
Body with ostia
Most are filter feeders / suspension feeders
1 family is carnivorous

6. Anatomy of a Sponge:
Osculum
Spongocoel
Choanocyte
Amoebocyte
Mesohyl

7. Suspension Feeding & Gas Exchange

8. Sponge Reproduction: Asexual reproduction
Buds or gemmules
Sexually – most sponges are hermaphrodites
Cells become egg/sperm
Sperm released into water
Fertilization occurs in mesohyl (egg)
Zygote becomes flagellated larva that leaves in flow of water

9. Phylum Cnidaria
Jellyfish
Box jelly
Sea anemone
Coral

10. Main Characteristics Diploblastic, radial symmetry
Cnidocytes with nematocysts concentrated in tentacles
Gastrovascular cavity with 1 opening
2 layers separated by mesoglea
Gas exchange and excretion occur by diffusion

11. Discharging of Nematocysts

12. Structure cont… Nerve nets Contractile cells
Connect sensory cells to contractile cells
Sense organs around edge of body
Ex. photoreceptors
Contractile cells
Not true muscles
Act as hydrostatic skeleton

13. Cnidarians come in 2 forms:
Medusa – tentacles down
Polyp – tentacles up
Many alternate between medusa and polyp during life cycle

14. 4 Classes of Cnidaria
Hydrozoa Scyphozoa Cuboza Anthozoa

15. Cnidarians are Carnivores
Feed on fish, larva, comb jellies, other zooplankton
Sting prey with their tentacles
Mouth  gastrovascular cavity  mouth
Jellyfish.asf

16. A word about corals: Many have symbiotic zooxanthellae
Environmental issue: Coral Bleaching

17. Portuguese Man-of-War
Interesting Facts…
Portuguese Man-of-War
Colonial
Has sail-like float
Tentacles can grow up to 165 feet and are nearly invisible

18. More interesting facts…
Box Jellies
More toxic than Man-of-War
Stings can lead to heart failure within minutes
Tentacles may reach 15 feet

19. CTENOPHORA: THE COMB JELLIES
Diploblastic??; Biradial Symmetry
Swim with 8 rows of ciliary combs
Have 2 long tentacles with sticky cells
Colloblasts
Eat large amounts of fish larva & plankton
Mouth + 2 anal pores
Introduced/Invasive species (Black Sea)