1. Mollusks – a phylum of animals
“Soft bodied invertebrates”

2. Main Phyla of animals
Animal : Plant : Fungi : Protist : eubacteria : archeabacteria
Cnidaria
Echinoderms
Mollusks
Arthropods
Vertebrates
Cephalopods
Crustaceans
Bivalves
Gastropods
Bird
Insects
mammals
Arachnids
Fish

3. What makes a MOLLUSK a mollusk
All mollusks have a soft body with no skeleton at all.
Some mollusks have a shell to protect their soft bodies… but some don’t
They have a fleshy “foot” …sometimes several

4. Three Classes of Mollusks (mollusk = phylum of animal kingdom)
Bivalves
Gastropods
Cephalopods

5. Cephalopoda (head foot)

6. Cephalopod anatomy

8. Giant squid

9. Giant squids

10. Nautilus – only shell making cephalopod
Has about 90 tentacles!!!!
The inner chambers of the shell act as a swim bladder

11. Cuttlefish Think: Squid with a cuttlebone in it
Cuttlebone is not a “bone”… it’s an internal shell that is filled with tiny air pockets (think Styrofoam)

12. Bivalves – 1st class of mollusks Bivalves = 2 sides hinged
Clam Mussel
Oyster Scallop

13. Bivalve anatomy
Bivalves flow water into & out of their shell, gills do the gill thing, & they also filter the water – eating algae & waste from the water.

14. Oyster reefs
Oysters build on each other, saves in making the second shell sometimes!
1 oyster filters 50 gallons of water per day

15. Less Oysters = dirty water
One adult oyster filters 50 gallons of water/day
Galveston bay use to be filtered through oysters once every week by huge oyster reefs
Oysters are harvested for food a lot.
Oyster populations have declined
Water is not naturally filtered as much.
Oysters have to live 3-4 years before mating so it can’t be fixed real fast.. But it can be fixed.

16. Gastropoda = “stomach foot” (2nd class of mollusks)

17. Gastropod shell diversity

18. Gastropod anatomy

19. What do snails eat? Most snails are herbivores- eat algae
Some snails eat dead things – detritus
But some can be predators.

20. Cone snails

21. Killer snails

22. Cone snails hunting Net hunter (not a harpoon, general sedative)
National geographic video
Nemo eaten by a snail
Fish stabbed and swallowed

23. 2 general ways for Mollusks to reproduce
Bivalves
Broadcast spawn – never meet (common in most fish)
Gastropods & Cephalopods
Modified reproduction
A packet is passed

24. Bivalves – the strangest reproduction
Example : freshwater mussel
Lives in almost all rivers, lakes and streams in this country!
INFECT most fish in all rivers, lakes and streams

25. How do they get in the fish?
Most common… just passively by fish breathing water

26. Gastropods = true hermaphrodite
What is the most common fact known about snails/ slugs (not the salt thing, even more basic … )
Most are hemaphrodites.

27. Cephalopods
While their skin is most interesting… they have unusual reproduction. – it is basically invitro fert.
Male only delivers a packet
Female stores it in a
special pouch
Female can choose
later which packet
to use!

28. Now – for something entirely new the Nudibranch (naked gill)
A Nudibranch is a gastropod that has abandoned its shell.

29. What is a nudibranch?
A nudibranch is a sea slug that eats coral/jellyfish.