1. Mollusks

2. General Characteristics
Kingdom: Animalia
Phylum: Mollusca “soft body”
Class: Cephalopoda “head-footed” (squid)
Examples of Mollusca
Clams
Snails
Slugs
Octopuses

3. Groups of Mollusks Classified according to their foot and shell
Three major classes of mollusks
Gastropods
Bivalves
Cephalopods

4. Characteristics 112,000 species Coelomates
Soft body with internal or external shell
Larval stage called a trochophore
Body plan:
Foot – takes on many forms
Mantle – covers the body
Shell – (present in most)
Visceral mass – internal organs

5. 7 survival systems Feeding & Digestion Excretion
mouth, anus and complex stomach
radula-help the mollusks scrape algae and force food backward
Some filter feed-through their gills
Tentacles- grab and hold prey
Excretion
carried out by a pair of nephridia (earthworm also had this)
Empties into the mantle cavity

6. Circulatory Respiration Response
Open circulatory system- gastropoda & bivalvia
Closed circulatory system- cephalopoda
Respiration
Use gills to exchange O2 and CO2
Response
Mental capacity like that of a cat
Largest eyes among animals
Complex nervous system
Nerve ring located around the mouth with a nerve cord connected to ganglia

7. Reproduction Movement Internal fertilization (cephalopods)
External fertilization
Movement
Varies among classes of mollusks
Gastropoda- crawling
Bivalvia- sessile
Cephalopoda- rapid swimming

8. Gastropods snails, slugs, limpets and nudibranchs
Shell-less or single shelled
Move by a muscular foot
Some are poisonous, bright colors

9. Bivalves
Things with two shells

10. Cephalopoda octopi, squids, and cuttlefish
soft-bodied , head is attached to foot
foot is divided into tentacles with sucking disks
small internal shells or no shell at all
Squid have a modified shell called a pen
most complex of the mollusks

13. Echinoderms “spiny skin”

14. General Characteristics
Invertebrates
No cephalization (no head region)
Deuterostomes- recall from earlier what this means?
Habitat- marine environments
Examples:
Sea stars
Sand dollars
Sea urchins
Sea cucumbers

15. Unique Characteristics
Endoskeleton
Made up of plates called ossicles
Water-vascular system
Tube feet
Extensions that aid in movement, feeding, respiration and excretion