1. Chapter 9 - Mollusks

2. Body and Structure 3 Layers of Shell
Head-Foot: Includes, head, foot, and sensory organs (eyes, ears, etc)
Visceral Mass: Includes organ systems (digestive, circulatory, etc)
Mantle: Tissue that covers and protects soft part of body, hangs from each side of body
Mantle Cavity: Space that is formed between body and mantle
Radula: Tissue that contains teeth and is in all types of mollusks except bivalves, used for tearing, biting, etc
3 Layers of Shell
Periostracum (outermost)
Prismatic (middle)
Nacreous (innermost)

3. Chitons and Scaphopods
flattened bodies, covered by eight shell plates hidden underneath mantle
use flat foot to attach to rocks in intertidal zone
roll into ball for protection
shell commonly called “tusk shell”
opens at both ends, foot used for burrowing and protrudes from larger end
water enters and exits smaller end, which brings in oxygen and removes waste
uses foot to capture prey

4. Gastropods size can range from microscopic to larger than 1 meter
if it possesses a shell, it is always one piece (univalve)
as the animal grows, the whorls of the shell also increase in size
can withdraw into safety and close the aperture (opening) with cover called operculum
Nudibranchs: lack a shell, usually brightly colored and bizarrely shaped because of gills and appendages

5. Tunicates
Mostly sessile animals that are widely distributed in all seas. Named after their body covering called the tunic.
Sea Squirts
Have cylindrical bodies and two tubes, one for sucking in water and one for pushing out water.
Protect themselves by blasting water out of their excurrent siphon
The mucous web filters water out leaving only plankton.
3 types: Colonial, Solitary and Compound.
Tunicates can regenerate their damaged body parts.

6. Tunicates Salps Larvaceans Free swimming tunicates.
Incurrent and excurrent siphons on opposite sides.
Larvaceans
Free swimming tunicates.
Release the mucous they use for feeding every 4 hours creating a fog in the ocean described by divers as “swimming through a snowstorm

7. Tunicates Cephalochordata (Lancelets)
An Eel-like, laterally compressed being.
4-8 centimeters
Like to burrow in the sand leaving only their head outside to catch food particles swimming by.
Reproduce sexually
Majorally popular for fishing in China.

8. Bivalves Mollusks with shells divided into 2 jointed halves
Called valves
Includes
Clams
Oysters
Mussels
Scallops
Shipworms
Body
Shells hinged by ligaments
Adductor muscles
Close valves
Foot
For movement
Inhalant and Exhalant openings
“Soft-Bottom Burrowers”
burrow into sand
Attached Surface dwellers
Thread-like secretion
Attaches bivalves to surfaces
Unattached Surface Dwellers
Move through jet propulsion
Boring Bivalves
Burrow into wood or stones
Reproduction
Sperm and egg are shed into the water

9. Cephalopods Cephalopods Means “head footed”
Have tentacles with suction cups
Octopus, squid, cuttlefish
Nautiloids
Subclass Nautiloidea
Large coiled shell
Septa
Separated chambers
Siphuncle
Connecting tissue to the shell
Removes seawater from the new chambers as they form
Tentacles
Coleoids
Cuttlefish, Squid and Octopus
Carnivores
Body developed to catch prey
eye-sight, tentacles, beak
Reproduction
Different sexes
Mating rituals
Spermatophore
Tentacle used for making sperm
Oviduct
Tube for releasing eggs
Fertilized eggs are raised out of the female body

10. Arthropods -The largest phylum of creatures on Earth
-Animals with jointed appendages
-Exoskeletons that are composed of a tough polysaccharide called chitin.
-They also perform molting with their exoskeletons
-Arthropods have what is called an open circulatory system: They have no arteries, veins or capillaries.
-Instead blood is carried through sinuses

11. Chelicerates
-Have a pair of oral appendages called chelicerae and lack mouth parts for chewing food.
-Food: They are able to eat solid food such as small invertebrates
-Reproduction: Aquatic chelicerates use external fertilization
-Have six pairs of appendages that are uniramous.
-Do not have antennas

12. Mandibulates
-Have appendages called mandibles that can be used for chewing food.
-Jawlike structured mouth
-Have 10 legs but first pair are modified to be pincers
-Have a pair of antennas
-Reproduction: Mostly dioecious, or brood eggs (External reproduction)
-Food: Wide variation in food, depends on environment and availability

13. Echinoderms All have radial symmetry Found in all depths
They have tubed feet
Well known animals: Starfish,Sea Urchins, Sea Cucumbers

14. Starfish Majority are carnivores or scavengers
They can reproduce another ray if one is removed

15. Ophiuroids They avoid the light Suspension feeders
They cast “automize” when scared by a predator

16. Sea Urchins Known as Echinoids ---> like the hedgehog
Body closed in by endoskeleton
“Regular Echinoids” are urchins that can move

17. Irregular Echinoids Heart urchins and sand dollars
They burrow in the sand

18. Sea Cucumbers ”Respiratory trees” ----> form of gas exchange
Have oral tentacles to help them eat
Release “Cuvierian Tubules” ----> the stickiness gives them time to escape from the predator.

19. Crinoids “Sea Lilies” ----> look like flowers
They cling to the bottom for long periods of time, this is called cirri