1. Molluscs

2. Molluscs/Mollusks Over 200,000 species of molluscs
More marine species than any other Phylum
Most have soft bodies enclosed in calcium carbonate shell.

3. Structure Body covered by mantle, thin tissue that secretes the shell
Have ventral, muscular foot, for locomotion
Have head w/ eyes & sensory organs
Radula
unique to molluscs
ribbon of small teeth used to feed
made of chitin (highly resistant carbohydrate)

4. Body Functions
Nervous System - well-defined with a primitive brain; ganglia = “local brains” in different parts of body
Circulatory system – blood vessels & 2-chambered heart
Digestive system - usually includes a jaw, salivary glands, pharynx, esophagus, stomach, intestine and anus
Reproductive system – separate sexes & external fertilization 
Respiration system –gills

5. Types of Molluscs
All molluscs have basic body plan but greatly modified depending on class.
3 Main Classes:
Cephalopoda (Cephalopods)
Gastropoda (Gastropods)
Bivalves (Bivalvia)

6. Cephalopods Name means “head-footed” 650 species, all marine
Predators specialized for locomotion
Includes: octopus, squid, cuttlefish, & other fascinating molluscs

7. Class Gastropoda Largest and most varied class of mollusk
90,000 species
Gastropod (stomach foot)
Foot on ventral side (stomach)
Examples: Snails, limpets, abalones, nudibranchs

8. Snails

9. Nudibranchs

10. Class Bivalvia Body compressed and enclosed in a two valved shell
Very small head, no radula
Gills expanded and folded and used to filter out food particles as well as gas exchange
Strong muscles are used to close the valves

12. Clams
Giant Clam

13. Mussels
Oysters
Scallops

14. Arthropoda

15. Arthropods Arthropoda = jointed foot Largest phylum
Includes insects, spiders, centipedes, millipedes and crustaceans
Inhabit almost every environment on Earth

16. Arthropod Characteristics
Segmented Body
Bilateral symmetry
Jointed appendages: mouth parts and legs
Compound eyes
Exoskeleton: hard, chitonous external skeleton
Limits growth
Must molt

17. Classification

18. Biology of Arthropods Feeding Respiration Circulation
Can be parasitic, filter feeders, or detrivores
Respiration
Do Not have Lungs
Tracheal Tubes – extend through body
Air transferred through Spiracles
Marine arthropods have gills or book lungs
Circulation
Have ganglia or many hearts run along body

19. Subphylum Crustacea The majority of marine arthropods Gills
Includes: shrimps, lobsters, crabs
68,000 species
Gills
Skeleton hardened by calcium carbonate
Appendages used to swim and/or crawl
2 pairs of antennae = sense
“Green” gland = salt regulation
Ventral nerve chord
Complete digestive system

20. Subphylum Chelicerata
All have pinchers
Mouthpart called chelicerates
Two body sections: Abdomen & Cephalothorax
Nearly all have four pair of legs
Include:
Spiders, Horseshoe Crabs, Scorpions, Ticks

21. Insecta (Insects) Body divided into 3 parts:
Head, Thorax, & Abdomen
Three pairs of legs attached to the thorax
Have compound eyes
Sense taste & smell
Growth involves metamorphosis
Eggs  Nymph  Adult
Eggs  Larva  Pupa  Adult
Form societies: closely related animals; same species

22. Subphylum Uniramia Insects Have jaws 3 pairs of legs One pair antannae
Examples:
Centipedes : 1 pair of legs per segment
Millipedes : 2 pair of legs per segment

23. Sea Stars, Brittle Stars, Sea Urchins, Sea Cucumbers, & Crinoids
Echinodermata
Sea Stars, Brittle Stars, Sea Urchins, Sea Cucumbers, & Crinoids

24. Echinoderm Characteristics
Echinodermata = spiny skin
Endoskeleton
Secreted within the tissues
Water vascular system
Madreporite = where water enters
Tube Feet
Muscular extensions of canals
End in Suckers
Used for attachment, locomotion, & sensing stimuli
Pentamerous symmetry = 5 part
Larvae = bilateral symmetry

25. Behavior Carnivorous, detritus foragers, planktonic feeders
Reproduce by Spawning & Asexually
Regeneration
Protection = Spiny skins and spines
Predators:
Mollusks
Fish
Crabs and shrimps
Other echinoderms

26. Ecology and Range Only marine Various habitats
Intertidal zone to bottom of the deep sea trenches
Sand to coral reefs
Cold and tropical seas

27. Classes of Echinoderms