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Glossary for See Food by Guundie Kuchling For a printable version click here The animals shown in this book occur in most oceans of the world. Sea creatures can display striking colours and even the less colourful species can appear vibrant through light and water. Each prey species presented here is one of many possible sources of food for the respective predator. Algae: algae (singular alga) range from single-celled, microscopic organisms in the phytoplankton (see plankton) to giant multicellular forms (seaweed like kelp which grows up to 65 m in length). Algae include plants but also organisms which are both plant and animal. They use light to get the energy to live and grow and do not have to eat other organisms (this complex process is called photosynthesis and produces oxygen). Arrow worm: a slender marine worm, also called 'glass worm', with an almost transparent, symmetrical body, ranging from 10 to 80 mm in length. Together with copepods they are the commonest animals in the marine plankton. They hang motionless in the water, but when they sense movement they dart forward like a torpedo - propelled by their tail - to catch their prey with hooks. Arrow worms are all carnivorous (animal eaters), voracious feeders with mouths that can be enlarged to take prey almost as big as the worm itself. Bristle worm: a marine worm, either free living or inhabiting a tube. This worm shows many segments and bristles on each side of the body, from 2.5 cm to 50 cm in length or longer, and moves in a snake-like way. Found in most oceans, this species occurs from the shoreline to great depths. The free-living varieties can also be seen near the surface during reproduction. Ciliate (see-li-at): a single-celled plankton animal up to 2 mm in size, found in fresh and sea water. The body shows rows of cilia (hair-like extensions) which are denser around the mouth - which helps the animal catch food. Cone shell: a marine snail which paralyses prey with a long, venomous dart. Among the cone shells are fish eaters, worm eaters and mollusc eaters. This species is one of the most poisonous molluscs - so be careful when picking up shells from the beach where cone shells occur. Never touch any living cone shell! Crab: an omnivorous (both plant and animal eating) crustacean with freshwater, marine and terrestrial species. Different crab species can have a leg span from a few mm up to 4 m. 10 legs (4 pairs of walking legs, one pair of pincers for grabbing prey). Clione (klee-o-nay): a mollusc without shell that lives in the plankton. It is also called a sea butterfly because its body is drawn out into wing-like extensions. Many species are important as food for whalebone whales and basking sharks. Copepod (cop-ay-pod): a crustacean which propels forward with oar-like limbs. They range from less than 0.5 mm to 15 mm in size. Copepods are the most abundant animals in the marine plankton, and one of the most important food sources for larger animals like herrings, sardines, basking sharks and whalebone whales. Fish larva: baby fish can be part of the plankton, too. The larvae of many fish species drift in the tides and currents until they are strong enough to swim. Groper: large family of fish, mainly found in reef habitats with a size between 40-80 cm and a weight from 0.8 kg to 9 kg. Heliozoan (hay-lee-o-soan): a single-celled organism in fresh water as well as sea water, 40 - 200 micrometer (1 micrometer is 1/1000 of a mm). Heliozoans have armlike extensions (axopods) radiating outward from the cell. They are used for 1) floating in open water 2) crawling over firm structures 3) catching prey. These extensions give the heliozoans their sun-like appearance. They fuse together to catch, eat and digest big prey, and then separate again. Medusa: one of the two body forms in the life cycle of many species of sea jelly (see sea jelly), or a body form of the related Hydrozoans. A medusa is a tiny sea jelly, from a few millimeters to several centimeters or even bigger. Little medusae are part of the plankton, bigger ones swim actively by contractions of their bodies. Moray eel: this fish spends most of its life in holes and crevices, its size varies from half a meter up to 4 m in length. Noctiluca (nok-tee-luke-a): a single-celled animal in the plankton, up to 2 mm in diameter, with a tentacle for catching prey. The cell is filled with a gelatinous substance which helps the animal to float and drift like a balloon. Many noctiluca species have the ability to glow - the resulting light can be seen at night and is commonly known as 'sea sparkle'. Octopus: a marine mollusc (there is no trace of a shell in its body) with eight arms equipped with rows of suckers to catch prey. It ejects ink when threatened, crawls or swims and can camouflage itself by changing colour. The most intelligent invertebrate: the octopus can even be trained to perform tasks. Some species can change body shape to mimic parts of their environment (e.g. rocks) or dangerous animals (e.g. sea snakes, lionfish). Octopuses can reach an arm-span of up to 8 meters and a weight of up to 100 kg. The tiny blue ringed octopus is the most poisonous and deadliest mollusc in the world. Don't touch! Plankton: animals and plants which float and drift in sea water or fresh water. Phytoplankton are plants, confined to the water close to the surface which can be reached by sunlight. Zooplankton are animals, found in different depths of the sea. Zooplankton can be herbivorous (plant eating) or carnivorous (animal eating). Plankton undergoes daily cycles - moving from the surface to great depth in the sea. There is microplankton (e.g. ciliates) which can only be seen with a microscope and macroplankton (e.g. fish larvae) which can be seen with the naked eye. Plankton is the basis of all food chains in water (fresh water and sea water). Radiolarian (radio-lair-ee-an): a single-celled animal up to 2 mm in diameter with a wide variety of shapes and patterns. Most radiolarians are part of the marine plankton and can be found in all depths of the water. Like heliozoans, they have extensions (axopods) of their cell body, but they also have a protective shell. Rotifer (row-tee-fer): multicelled, often planktonic animals, less common in the sea, very common in fresh water, from the tiniest puddles to the largest lakes. They have a wheel of cilia around the mouth - hair-like structures for moving and bringing in food. Free floating rotifers use their foot as a rudder. Sea jelly: sea jellies (commonly called jellyfish, although this animal is not a fish) live on the surface and the deepest region of the sea. Most of them are passive drifters. They have a bell-shaped body with the mouth on the underside, surrounded by tentacles with stinging cells for defence and immobilising prey. Most jellies have a complex life cycle: they pass through two different body forms - the polyp (a cup-shaped stalk with tentacles) and the medusa (see medusa). Some species are highly toxic and dangerous to humans (e.g. box jellies). Sea star: most species have five arms (up to 1 m across), covered with a spiny surface, radiating out from a central disc. Their underside is equipped with numerous little tube feet which act as suckers. Their stomach can be turned inside out to digest large prey outside the body. Shrimp: a crustacean in salt or fresh water, with long legs and antennae, the front of the body covered by a tough plate, the carapace, with a spine-like projection. Shrimps can rapidly swim backwards. They can live in schools and are an important food source for larger animals (from fish to whales). Squid: a marine mollusc and a voracious predator. The shell (the "pen") is inside the body and looks like a clear piece of plastic. Squids can change colour for camouflage and expel ink when threatened. Usually from a few centimeters up to 60 cm in length, but giant squids can reach up to 18 meters (tentacles outstretched). In contrast to the related octopus, the squid has two long tentacles for catching prey (in addition to its 8 arms). Violet snail: up to 3 cm in size with a thin shell, this species makes its own raft from mucus and air bubbles. Clinging to its raft, the snail floats upside down on the surface of the sea and preys mainly on sea jellies. Wrasse: Wrasses are one of the largest, most diverse fish families in the sea, and are found worldwide except in Arctic and Antarctic seas. Most of them are brightly coloured and have strong teeth. 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