1. Molluscs, Arthropods, Lophophorates, Echinoderms, and Invertebrate Chordates

2. Molluscs Name means “soft- bodied”
Usually covered by shell made of calcium carbonate
Ex: chitons, snails (gastropods), clams (bivalves), octopods, squid,
Range in size from microscopic to giant

3. Body Structure:
Head-foot region
Covered by mantle
Used for locomotion
Can help form shell
Visceral mass
Radula  contains teeth
Adapted for scraping, piercing, tearing, or cutting pieces of food

4. Reproduction and development:
Mainly sexual
Can have separate sexes or be hermaphrodites
Type of feeding:
Herbivores, Carnivores, Filter feeders, Suspension feeders, Scavengers, Deposit feeders

5. Ecological roles:
Source of food and calcium
Hosts to parasites
Can cause commercial damage

6. Arthropods Name means “jointed-leg” Body Structure:
Paired jointed appendages for locomotion, mouthparts, sensory structures
Hard exterior (exoskeleton)
Made of protein and chitin
Sophisticated sense organs  highly developed nervous system
Segmented body

7. Reproduction:
Herbivores, Carnivores, Filter feeders, Suspension feeders, Scavengers, Deposit feeders
Chelicerates
Horseshoe crabs
Sea siders

8. Mandibulates
Decapods: crabs, lobsters, true shrimp
Mantis shrimp
Krill
Amphipods
Copepods
Barnacles
Ecological roles:
Food source
Common symbionts
Nutrient recycling
Can cause commercial damage

9. Lophophorates (Phoronida)
Sessile
Body Structure:
Lack distinct head
Feeding:
Possess lophophore
Feeding device
Also used for gas exchange
Ciliated tentacles around mouth

10. Reproduction:
Asexual by budding or fission
Some are hermaphrodites
Some have separate sexes
Phoronids  wormlike
Secrete a leathery tube around the body
Bryozoans
Brachiopods  lamp shells
Ecological roles
Filter feeders
Supply food
Fouling ship’s bottoms

11. Echinoderms Name means “spiny skin” Mostly benthic
Ex: sea stars, sea urchins, sea cucumbers
Body Structure:
Radial symmetry
Endoskeleton of calcium carbonate (ossicles)
Water vascular system
Used for locomotion, feeding, and circulating internal fluids

12. Reproduction
Asexual and sexual
Feeding
Herbivores, carnivores, filter feeders, deposit feeders, scavengers
Ophiuroids
Brittle stars, basket stars, serpent stars
Crinoids
Sea lilies, feather stars
Ecological roles
Source of food for molluscs, sea otters, spider crabs, and humans
Predators
Destroy kelp forests

13. Tunicates (Urochordates)
Sessile
Body structure:
Covered by a tunic composed of polysaccharides
Reproduction:
Asexual: in colonies
Sexual: hermaphrodites

14. Feeding:
Filter feeders on plankton
Ecological roles:
Channels nutrients for other organisms
Can have symbiotic relationship with photosynthetic bacteria
Widely distributed in all seas
Ex: sea squirts, salps, larvaceans

15. Cephalochordates Fish-like chordates (lancelets) Lack bones
Body resembles an eel
Reproduction:
Separate sexes
External fertilization
Feeding:
Feed on organic material from particles filtered from the water
Ecological role:
Channels nutrients for other organisms

16. Arrowworms (Chaetognatha)
In marine plankton (tropical water)
Body Structure:
Body is torpedo-shaped
Grasping spines around the mouth
Reproduction:
Hermaphrodites
Feeding:
Predators that feed on zooplankton
Carnivores
Ecological role:
Channels nutrients for other organisms