1. MOLLUSK

2. General
Mollusk
Informatiom
Sea Slug
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3. Mollusk Terms Phora = Bearing Mono = One Placo = Plate Cephalo = Head
LATIN LIVES
Phora = Bearing
Mono = One
Placo = Plate
Cephalo = Head
Scapho = Sword
Pelecy = Hatchet
Poda = Foot
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4. Phylum Mollusca Classes
Click on any Scientific Name to go to that Class
Aplacophora - mollusks without shells
Pelecypoda ( Bivalve) - clams, oysters, mussels, second largest species.
Cephalopoda – squid, octopus, chambered nautilus
Gastropoda ( Univalve) – snails, slugs, abalones, whelks, periwinkles, giant conch, most species
Monoplacophora - mollusks with one shell, ancient
Polyplacophora ( Amphineura) – chiton, eight plates, intertidal
Scaphopoda - a tubular shell - tusk shells
General information
Interesting Facts
Start Over
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5. Invertebrates with Soft Bodies “Mollusk”
octopus
They have existed for 600 million years.
Some are very primitive and some are quite intelligent creatures.
They are used commercially in many ways.
squid
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snail

6. Mollusk ~ Snail Second largest group in the animal kingdom
There are more than 150,000 living species of the mollusk.
Half of the species are marine.
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7. MOLLUSK ANATOMY
Mollusks vary greatly in the development of each of the three body sections.
Three main body sections
Head = Eyes, Mouth ( Radula –rasping sucking tongue) and Tentacles
Visceral Mass = Mantle which secretes the shell, and the gills, intestines, kidneys, heart.
Foot = large muscular organ to move the body.
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8. Mollusk Anatomy Visceral Mass Shell Coelom Mantle Heart Gonad
Nephridium
Esophagus
Stomach
Anus
Intestine
Gill
Mouth
Mantle Cavity
Nerve Cords
Foot
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9. Mollusk reproduction
Most mollusks have separate females and males; gonads are in the visceral mass ~ Sperm or eggs are produced by meiosis.
Snails are hermaphrodites bearing both female and male gonads in same individuals.
Sea Slug
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10. Class
Monoplacophorans
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11. Monoplacophorans
This is the deep- sea dwelling class that was the ancestor of all other mollusks.
These animals were thought to be extinct until 1952
At present, only a few living species are known to exist.
There are many fossils .
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12. Monoplacophorans
Nepolina
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13. Monoplacophorans
Fossil Specimens
Cyrtolites
Archinacella
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14. Class
Aplacophora
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15. Aplacophorans
These organisms lack shells and are worm-like in body form.
They have calcareous scales or spicules in their integument.
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16. Aplacophorans
Soleonogasters which also live on the bottom feed on cnidarians (Jellyfish – Corals).
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17. Class
Gastropoda
Whelk
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18. Mollusks Gastropoda (Univalve)
Class Gastropoda-
meaning stomach foot
Univalve = one valve or one shell
Conch
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19. Mollusks - Gastropods
snails, slugs, abalones, whelks, periwinkles, giant conch
Largest – giant conch – 1 foot length
Urosalprix – “oyster drill” bores hole in oyster and digests through the hole.
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20. Mollusks - Gastropods
Snails, nudibranchs, cowries, whelks
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21. Sea Slugs
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22. Nudibranchs with
symbiotic algae
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23. 11/23/2018

24. Glaucus atlanticus
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25. Abalone
The Abalone shell is used to make jewelry
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26. Abalone
Abalone is served in fine restaurants
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27. Periwinkle
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28. Periwinkle Periwinkles feed on algae and seaweed.
They are found at the water's edge on Mash grasses.
They move up and down the grasses in synch with the tides.
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29. Snails As Bird food The endangered Whooping Crane eats snails
Snails provide an immense amount of food for waterfowl in the wetlands.
Mallard - 16%
Pintail - 15%
Blue winged Teal - 38%
Northern Shoveler - 40%
Gadwall - 4%
Whooping Crane – 60%
The endangered
Whooping Crane
eats snails
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30. Class
Pelecypoda
Oyster Shell
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31. Phylum Mollusca Class Bivalvia ( PELECYPODA)
Class consist of;
clams, oysters, scallops, mussels
mussels
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32. What are the shells of mollusks made of?
Oyster Shells
Calcareous material that resembles limestone
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33. Scallop
Eyes
Gills (Cilia)
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34. Clam
Gills with Cilia
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35. What do clams use for digging into the sand?
A muscular, hatchet-shaped foot extends from
between the shells and is used for digging.
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36. Class
Cephalopoda
Octopus
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37. Cephalopoda
Class Cephalopoda are among the most active, interesting and intelligent of the Mollusk.
Cephalopoda means head-foot. Their head is attached to the foot which become tentacles
octopus
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38. Class Cephalopoda octopus
Shell reduced & internalized in squid ( beak)
No shell in octopus
Largest invertebrates
Possess eyes and tentacles
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39. Mollusks - Cephalopods
All are carnivorous
Siphon allows jet propulsion in squid
Defenses include ink (squid, octopus) and change in coloration of octopus
octopus
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40. Mollusks - Cephalopods
Squid, chambered nautilus, cuttlefish, octopus
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41. Squid
Shell reduced to pen made of chitin
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42. Cuttlefish
CuttleFish
Cuttlefishes have Carbonate shells
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43. cephalopods
The only cephalopods with a shell are a few species of nautiluses
Nautilus means shell with chambers.
Nautilus
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44. Class
Polyplacophora
Chiton
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45. Class Polyplacophora
Habitat: Chitons inhabit the intertidal and subtidal regions.
They live under or on rocks with a very tight grip to protect them from waves.
Each one consists of Eight plates
Diet: Encrusting plants and animals
Reproduction: Chitons are dioecious, meaning there are female chitons and male chitons.
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46. Chiton
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47. Gumboot Chiton It is the largest species of chiton in the world,
It can grow up to 30 cm in length
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48. Class
Scaphopoda
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49. Scaphopoda
The Scaphopoda are known as the "tusk shells" because their shells are conical.
The scientific name Scaphopoda means "shovel foot", which refers to the "head" of the animal. It lacks eyes and is used for burrowing into marine mud and sediments.
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50. Scaphopoda
The most distinctive feature of scaphopods is that the tubular shell is open at both ends,
Not just one end as in most molluscs.
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51. Life is Tough
Scaphopods live their adult lives buried in sand or mud, with their head-end pointed downwards.
Only the narrow posterior end of the shell sticks up into the seawater for water exchange and waste expulsion.
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52. Interesting
Facts About
Mollusk
Rapa Whelk
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53. Introduced Species Rapa Whelk
Came from the Sea of Japan
The Rapa Whelk is destroying the Mid-Atlantic natural Whelk habitat
No predators
Reproduce rapidly
VIMS has a bounty for catching them
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54. The role of the Mollusk
Can be a check on pollution levels, since some are filter-feeding bivalves
Pouch Snails provides a sign for what the water quality is; (the dominance of pouch snails signifies poor water quality)
Mollusk provide 16% of
the Mallard Ducks Diet
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55. Mollusks ~ Reproduction
Some hermaphroditic
mollusks, such as
certain oysters switch from one sex to the other.
Sometimes
producing eggs, and sometimes sperm
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56. Mollusks Sea Hare Those without shells;
May spend daylight hours under rocks
Some sea hares have a special “ink” they squirt.
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57. Mollusks ~ Make Pearls
Oyster with Pearl
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58. Mollusks Facts Snails and other mollusks never seem to develop cancer;
Sea Slug
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59. Mollusks There are some negative relationships with humans
Land slugs and snails are plant eaters that do damage to crops
Shipworms will damage wood ships- “termites of the sea”
Shipworms
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60. THE END
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