Mollusks are soft-bodied invertebrates that mostly have shells covering their bodies. They have complex organ systems and three main body parts: a muscular foot, mantle, and visceral mass containing internal organs. There are three main classes of mollusks: gastropods with one shell, bivalves with two attached shells, and cephalopods with an internal skeleton. Many mollusk species are used as food sources for humans while others like golden kuhol have become agricultural pests. Certain species can also transmit diseases.

1. MOLLUSKS

2. PHYLUM MOLLUSCA
•Mollusks are soft-bodied invertebrates
with most of them covered by a shell.
•They have complex respiratory,
reproductive, circulatory, digestive and
excretory systems functioning together
for their survival.

3. THREE BODY PARTS
•Muscular foot – used for locomotion
•Mantle – produces the shell
•Visceral mass – contains the internal
organs

4. THREE CLASSES
•Gastropods
•Bivalves
•Cephalopods

5. GASTROPODS
•Also called UNIVALVES because they only
have one shell.
•They are mostly marine with freshwater
and terrestrial members.
•Those living in seas have gills for
breathing and those on land use the lining
of their mantle as lungs.

6. LIMPET

7. SNAIL
(suso)

8. SLUGS
(kuhol)

9. ABALONE

10. NUDIBRANCHS

11. BIVALVES
•These mollusks consist of two shells
attached to each other
•Some are attached to rocks while others
remain in the sand or mud
•They use their mantle cavity to feed by
trapping suspended particles in water and
for gas exchange

12. MUSSELS
(tahong)

13. OYSTERS
(talaba)

14. CLAMS
(halaan)

15. TRIDACNA
(taklobo)

16. CEPHALOPODS
•These organisms have internal skeleton
•Some have external skeleton while others
are shell-less
•They are the most active mollusks, moving
very fast using arms and tentacles in
catching prey

17. SQUID
(pusit)

18. CUTTLEFISH

19. CHAMBERED NAUTILUS

20. OCTOPUS

21. Many mollusk species are utilized
as food like tahong (mussels),
talaba (oysters), halaan (clams),
scallops, and kuhol or suso to
name some. Other species are
made into decorative items

22. Golden Kuhol, however, has
become a pest to rice and other
crops. They eat a lot of plant
leaves and reproduce rapidly.

24. The giant African snail Achatina
fulica was found to be an
intermediate host to a rat
lungworm that causes meningitis.

26. ACTIVITY
Name the following organisms
and classify if they are
gastropods, bivalves or
cephalopods