EJC Honours Day 2013

Transcription

1 EJC Honours Day 2013

2 A soft-bodied animal, typically with a hard shell of one or more pieces. It is an invertebrate meaning it doesn t have a backbone and is of the phylum (group) Mollusca. The word mollusk comes from the Latin meaning "soft, flexible, tender" referring to the mollusk's soft body parts. Mollusk is another name for shellfish. Examples include snails, mussels, oysters, etc.

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5 Mantle An organ covering the soft parts of a mollusk. It secretes calcium carbonate to create the shell. Foot The largest visible portion of a mollusk other than the shell. It is the soft part that protrudes from the shell and touches the surface of whatever the mollusk is crawling on. Teeth/Radula More like a jagged tongue than they are like teeth. Used to chew food and scrape algae from rocks.

6 Ribs Any raised ridges on the surface of a shell. Valve The shell of a mollusk. Dorsal border The edge of a bivalve's shell where the hinge is located.

7 Apex The tip or point of the shell. Operculum A hard structure situated at the end of the foot, and is used to seal off the entry to the shell. You can think of it as a combination shoe/door. Canal A structure to accommodate siphons, or tubes, that extend from the mantle. These siphons act as snorkels, enabling the animal to continue to draw in a water current containing oxygen and food into their bodies. The siphons are also used to "taste" the water, in order to detect prey from a distance.

8 Habitat Land Sand/Rubble Rocks Corals & Reefs Mud & Mangroves Continental Shelf Deep Ocean Mollusks Snails Olives, Helmets, Pipis (clams), Sand snails Limpets, Chitons, Mulberry Cones, Tritons, Cowrie, Clams Bubbles, Ears, Murex, Whelk, Oyster Scallops, Cones, Tritons, Tusks, Augers, Volutes Nautilus, Horn Shell

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20 They glide or creep with their foot (for example, snail). They move or swim by jet propulsion (ejecting water from their body), for example, squid. Some, like the oyster, attach themselves to rocks and feed by filtering small food particles from water that flows through them.

21 Some mollusks hide in their shells when threatened. Others use poisons. Some camouflage themselves. Many octopus, squid, etc. warn off predators by being brightly coloured and unpleasant tasting. Some defend themselves by rapid colour changes or by spraying ink or a jet of water at an aggressor.

22 Many of them become covered with barnacles or other sea creatures that make them look like their surroundings. If a shell becomes damaged the mantle does repair work. Many shells, including most oysters, have the power of producing a secretion, which covers up any irritation. This is how pearls are made.

23 Shells are formed when numerous secretory glands of the mantle produce calcium carbonate which is laid in layers until the shell is complete. The calcium carbonate hardens into a shell. The apex of the shell is formed first, and as the animal grows, more is added to the shell at the opening. These glands along the edge of the mantle are of different sizes and shapes, so that the ribs produced by the glands give each species its special shell. Scattered among these glands are others, which secrete pigments, producing the varied designs, and still others which produce horny substances.

24 Food Money Buttons Adornment/Decorations Fret board markers Utensils Chemistry Dye Lime

25 Univalves Mollusks with one shell. Also known as gastropods. Largest class of mollusks. May live in water or on land. Examples include snails and slugs.

26 Bivalves Mollusks with two shells joined by a hinge at one edge. Live in water but not on land. Do not have teeth (radula), they feed by siphoning and filtering large particles from water. Use their closely-fitting valves as a defense against predation and drying out. Examples include clams, scallops, mussels and oysters.

27 Multivalves Very small class containing only the chiton, lepas and pholas. Have a shell jointed in eight places, held together by a surrounding girdle. Live on hard surfaces such as rocks.

28 Tusk/Tooth Shells Live only in the sea. They are in one piece with a tube open at both ends. These lie buried in the mud in deep water, with only their narrow ends protruding and are not very well known.

29 Cephalopods Also known as Armed Mollusks. Have at least 8 arms. Some have shells externally, internally, or no shell at all. They live only in the sea and many are well known, such as the cuttlefish, squids, octopus.

30 A pearl is a hard, rounded object produced within the soft tissue (specifically the mantle) of a living shelled mollusk. The finest quality pearls have been highly valued as gemstones and objects of beauty for many centuries, and the word pearl has become a metaphor for something rare, fine, and admirable. Marine pearl oysters and freshwater pearl mussels. Layers of nacre, more commonly known as "mother of pearl". It is a combination of calcium carbonate and conchiolin.

31 As a response to an irritant inside its shell, the mollusk creates a pearl to seal off the irritation. The commonly held belief that a grain of sand acts as the irritant is in fact rarely the case. Typical stimuli include organic material, parasites, or even damage that displaces mantle tissue to another part of the animal's body. These small particles or organisms enter the animal when the shell valves are open for feeding or respiration.

32 Pearls are fairly rare and highly valuable. Jesus likened eternal life to a pearl highly valuable and also free for the taking. A second lesson can be drawn from the way a pearl is made. It starts out as an irritant which the mollusk covers and turns into an item of beauty. In the same way, Christ covers our irritants with his robe of righteousness, converting us from miserable, doomed sinners into heirs of the eternal kingdom.

33 h_honors_answer_book/nature/shells a/82/assets/0017/9732/shells_honour_trai ner_s_notes_powerpoint_presentation.pdf als/mollusks.htm imals/marine_invertebrates/molluscs

34 Text Genesis 1:20,21 Psalms 104:25 Isaiah 50:2 Job 28:18 Description Water creatures were created on what day? The number of water creatures is innumerable. Water creatures perish out of water. Job considered coral of great value. 1 Kings 4:33 Solomon was acquainted with marine life. Matthew 7:6; 13:45,46 Jesus twice used a shell product to teach a spiritual lesson. Acts 16:14 A businesswoman was engaged in selling the famous purple dyes secured from the shellfish Mediterranean Murex. 1 Timothy 2:9 Paul does not support the wearing of pearls. Lev. w11:9,10 Shell creatures are unfit for food. Rev. 21:21 The twelve gates of Holy City are twelve pearls.