1. Mollusca

2. CHARACTERISTICS: Mollusks are soft bodied animals that usually have an internal or external shell 4 Main body parts –foot – crawling, burrowing and tentacles for capturing prey –mantle – thin layer of tissue covers most of the mollusks body, like a cloak –shell – made by glands in the mantle that secrete calcium carbonate –visceral mass – contains internal organs

7. Characteristics cont. herbivore, carnivore, filter feeder, detritivores, parasites radula – flexible tongue shaped structure which hundreds of tiny teeth are attached. (scrap algae or dig through shell) siphon – tube like structure through which water enters and leaves the body marine mollusks – gills land mollusks – use mantle cavity (oxygen diffused over membrane) open circulatory system – blood is pumped through vessels by a simple heart closed circulatory system – (octopi, squid) – can transport blood more quickly release nitrogen containing waste – ammonia

8. Bivalvia – any mollusk that has a shell divided into 2 valves hinged at one side –Examples – clams, oysters, mussels, scallops Characteristics –shell made of calcium carbonate –most dioecious – separate sexes, some can alter gender, external fertilization –most obtain food and oxygen by filter feeding siphon system –no head, teeth or eyes

11. Most of the time all we see of most clams is simply a siphon protruding from the sediment or a coral head. Several different types of siphons are found, however, and experts can sometimes tell the clam species in a given area simply by observing the siphon.

13. Clam Anatomy

14. Bivalvia Char. Cont. –strong muscular foot used for burrowing or locomotion –open circulatory system –feeds on plant cell material –use sticky threads to attach themselves to rocks –can use shell by rapidly flapping their shells when threatened –some scallops have dozens of eyes? –adductor muscles used to close and open shell –no radula –Labial palps – on either side of the mouth, sort filtered food particles –gills –oldest part of shell – umbo

15. Scallop eyes Many people know of scallops as a tasty seafood, but most have never seen a living scallop. Scallops are diverse, with over 300 species of scallops living on the ocean floor worldwide. They range from shallow waters to areas several hundred feet deep. Scallops, classified as bivalve mollusks, hide some amazing secrets. For one, about sixty primitive tiny bright blue eyes eyes reside in rows along a scallop’s mantle edge to detect motion, light and dark. A scallop can easily regrow any lost or injured eyes. Although these eyes may or may not produce clear images, the ability to sense an object moving with the speed of one of the scallop’s predators allows the scallop to save its skin (or to be scientifically correct, its shells) by either shutting immediately or swimming away.

16. Scallop eyes

17. eyes

18. Secondly, scallops possess an unusual trait which most other bivalves lack: the ability to swim. Scallops can propel themselves away from danger by contracting their powerful muscles and "clapping" their shells together, forcing water out through openings on both sides of their shell hinge. They can move forwards backwards, make turns, and right themselves in this fashion. Scallops swim particularly when faced with a predator (e.g., a seastar). Otherwise, if left relatively undisturbed, scallops are fairly sedentary creatures that lie on the seafloor as they feed by filtering microorganisms from the water. Those tasty cylindrical or disk-shaped morsels of scallop meat found in seafood shops are the adductor muscles that in the living scallops make their unique swimming ability possible.

19. CLAM ANATOMY 1. This is the clam's left mantle. The mantle secretes the shell and is attached to it along the pallial line seen on the inner surface of an empty valve. Note: the left mantle was detached from the left valve when it was removed. The black arrows show the border of the left mantle

20. CLAM ANATOMY CONT. 2. This is the anterior adductor muscle, a major muscle for closing the valves 3. This is the posterior adductor muscle, a major muscle for closing the valves.

21. CLAM ANATOMY CONT. 4. This is the pericardial cavity, a region covered with a thin, dark membrane that contains the heart, kidney, etc. 5. This is the margin of the right mantle. The right and left mantles join together to form the incurrent and excurrent siphons 6. This is location of the incurrent and excurrent siphons.

22. Scaphopoda – shovel foot –Examples – Tusk shells Characteristics –live only in salt water –external fertilization –shells shaped like long thin fangs –draws water in through small tip of shell that sticks out of the sand or mud. Water flows into the mantle cavity where oxygen is absorbed directly into the blood – size 2mm – 15 cm –shell open at both ends –no gills, eyes, heart, or blood vessels (open circulatory) –radula – tooth, grinds up food

23. Tusk shell

25. Cephalopods – head foot –Examples – Octopus, squid, cuttlefish, and nautilus Characteristics –nautilus – up to 90 tentacles, no suckers, but contain sticky mucus like covering »sexual reproduction »male has 4 tentacles that form a spandex – transfers sperm »carnivores »primitive eyes »jaw/radula »siphon – bent tube through which fluid can be drawn over the edge of one container into a lower container by means of air pressure

26. Cuttlefish

28. NAUTILUS Nautilus are primitive cephalopods and are true living fossils. They are normally found in cool deep waters off of coral reefs, and require the high pressures in deep water for both good health and successful growth, and as such they have no place in home aquaria. They are subject to a fishery for their shells and recently over 10,000 of them were collected around New Caledonia in a few months. This effectively destroyed one population of them.

31. Cephalopoda cont. –most highly developed of all mollusks, large brain –dioecious –males of specialized tentacles to transfer sperm –modified foot – tentacles –gills –excellent eyesight –cephalo – head –poda – footed type animal (divided into tentacles or arms) –swim rapidly –chromatophores – allow animals to change colors and patterns

33. Squid anatomy

35. Giant squid video Scientists capture giant squid on camera - Science - MSNBC.comScientists capture giant squid on camera - Science - MSNBC.com

36. Cephalopoda cont. –teeth like hooks can dig into a shell/ radula, carnivores –digestive system is muscular –propulsion system used to move and keep water out –octopus is the only cephalopod that doesn’t have a shell – others have small internal shells, nautilus – external shells –closed circulatory shell –bronchial hearts – each cephalopod contains two hearts working as one –squid eaten by sperm whales –squid 17 meters – 6,000 Ibs. –octopus and squid shoot out ink when attacked

38. Polyplacophora – poly = many, plac = plate, phora = carry, ie: bearer of many plates –Examples – Chitons Characteristics –8 piece segmented shell, bilateral symmetry –inhabit rocky shorelines and shallow ocean bottoms –rolls itself in a ball for protection –will create a vacuum for protection, to hold chiton in place –move in same fashion as snails, foot secretes small amount of mucous

39. Cont. –eat seaweed and algae –only a few centimeters long, 8mm – 33cm –gills for respiration –closed circulatory system –poorly developed ganglia –nephridia – primitive kidney for excretion –dioecious, external fertilization –radula used to scrap algae

41. Polyplacophora A worm-like chiton from the South Pacific. Most chitons have well- developed, easily visible dorsal plates, but in a few species the plates are greatly reduced. A few of these species also have an elongate, worm-like body. Shown here are an adult, a juvenile and a young chiton.

43. Light microscope photograph of Rhyssoplax radula showing magnetite- tipped (black) tricuspid teeth

45. Gastropoda – stomach foot –Examples – Pond snail, limpets, abalones, land slug, and whelks Characteristics –single shell carried on back –broad foot crawls across the rocks or digs into the sand –spiral shell –shell is protection for animal –some retreat into the shell and close by using Operculum – plate attached to foot, allows them to withstand long periods of dryness

46. Gastropoda cont. –some have modified foot for swimming and used for reaching –pteropoda – winged feet –some have no shell – some squirt ink for protection, taste bad or poisonous –opisthobranchiata – sea slug, lose shell by adult –sea hares are hermaphrodites –some can seal shell and with stand long periods of dryness –radula

47. Snail Anatomy