1. Chapter 8: Sponges, Cnidarians, Comb Jellies, and Marine Worms

2. What are Animals? Multicellular Eukaryotic (lack cell walls)
Cannot produce their own food (heterotrophs)
Can move (exception: adult sponges)

3. Vertebrates: have a backbone (vertebral column)
Invertebrates: do not have a backbone (no vertebral column)
Majority of marine animals

4. Sponges (Phylum Porifera)
Simple
Asymmetric
Sessile (cannot move)

5. Structure and Function
Full of tiny holes/pores called ostia
Water circulation (nutrients and oxygen)
Carries away wastes
Lack tissues and organs
Size is limited by ability to circulate water through its body

6. 3 possible body plans
Asconoid (simplest)-tubular and small
Syconoid (body-wall folding)-internal pockets
Leuconoid (highest degree of folding)

7. Nutrition and digestion:
Suspension feeders (filter feeders)  Get food from water
Reproduction
Sexual
Hermaphrodites
Asexual
Budding  pinching off to form new organism
Fragmentation  pieces form new organism

8. Ecological roles
Can produce chemicals that can kill coral or inhibit growth
Can provide camouflage and protection for animals
Can produce chemicals that prevent organisms from settling on their surface or to deter grazing
Hosts to other organisms
Recycles calcium to seawater

9. Cnidarians (Phylum Coelenterata)
Ex: jellyfish, hydra, coral, and sea anemones
Radial symmetry

10. Structure and Function:
2 different body plans
Polyp: benthic form
Cylindrical body with an opening a 1 end (mouth)
Surrounded by tentacles
Medusa: free-floating stage
Gelatinous material between layers of body called mesoglea

11. Stinging cells (cnidocytes)
Common on tentacles and outer body wall
Can also release toxins

12. Nutrition and digestion
Digests prey in gastrovascular cavity
Filter-feeders
Can be carnivores
Paralyze prey with toxins
Reproduction
Asexual  polyp stage
Sexual  medusa stage

13. Ecological relationships
Predators that feed on a variety of prey
Provide habitats for organisms (ex: corals)
Host symbionts that aid in nutrition and help them grow

14. Ctenophores (Comb Jellies)
Structure and Function:
Transparent bodies
Lack stinging cells
Planktonic
Eight rows of comb plates used for locomotion
Made of large cilia
Weak swimmers
Found mostly in surface water
Radial symmetry
Luminescent at night

15. Nutrition and Digestion
Carnivorous
Reproduction
Hermaphrodites
Shed eggs and sperm directly into the water column
Few species can brood eggs in their bodies

16. Marine Worms Most are benthic Structure: Elongated bodies
Lack external hard covering
Gain support for body from fluid in body compartments
Hydrostatic skeleton

17. Flatworms Flattened bodies Structure: Head and posterior end
Free-living or parasitic
Bilateral symmetry
Ex: flukes and tapeworms

18. Nutrition and digestion:
Chemical-detecting organs called chemoreceptors
Carnivorous
Can subdue prey by entangling it in mucus and suffocating it
Can stab prey
Digestion in gastrovascular cavity
Reproduction:
Asexually  regeneration
Sexually
Hermaphrodites
Can fertilize each other
Internal fertilization
No larval stage

19. Nematodes Roundworms 12,000 species Structure: Round, slender body
Elongated
Tapered at both ends
Nutrition/Digestion:
Scavengers, parasites
Carnivorous, free-living
Reproduction:
Most are hermaphroditic
Some can have separate sexes

20. Annelids Segmented Structure and Function: Body wall has muscle
Skin has setae (small bristles used for locomotion, digging, anchorage, and protection)

21. Feeding and digestion: Can have jaws or teeth Active predators
Chemoreceptors monitor water currents
Filter-feeders
Reproduction
Asexual
Budding
Regeneration
Fragmentation
Sexual
Separate sexes
Gametes shed into body cavity where they mature

22. Ecological roles:
Burrowing aids in nutrient cycling
Burrows provide habitats for other species
Feed on microorganisms and detritus

23. Examples of Annelids
polychaetes
echiurans
pogonophorans