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Jellyfish, Hydroids, Corals, & Sea Anemones

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1 Jellyfish, Hydroids, Corals, & Sea Anemones
Cnidarians!!!!!!!!!!!!!! Jellyfish, Hydroids, Corals, & Sea Anemones









10 Basic Information Radial symmetry
Contain organisms such as jellyfish, hydroids, corals, and sea anemones Cnidocytes- stinging cells in their tentacles that are used for protection and killing prey.

11 Two Different Body Plans
1. Polyp- mostly benthic, cylindrical, mouth is at one end and is surrounded by a ring of tentacles. Ex- corals and sea anemones 2. Medusa- free floating stage that is commonly known as a jellyfish.


13 Both stages have the following:
Most of them do exhibit both during their life cycles, except corals and sea anemones Both stages have the following: Epidermis= outer layer of cells Gastrovascular cavity that is rather large and is lined by cells called the gastrodermis. Mesoglea- between the epidermis and gastrodermis and it’s a gelatinous material where jellies get their names from.

14 Stinging organelle-> called cnida and some function in locomotion while others function in capturing prey and defense. Most are of the spearing type called nematocycts= which is hidden away in a tiny capsule inside the cell and when activated it shoots out like a harpoon. When the cnidocil, a short bristle like structure, comes into contact with prey or another object, it gets activates and shoots out the nematocyst. Some nematocysts have a thread like structure that wraps around the prey and strangles them.



17 Dangerous Box Jellyfish- kills a person in minutes (3-20)
Portuguese Man of War M

18 Leatherbacks and Nudibranchs
Leatherbacks use them as a toy to play with and to eat! o

19 Nudibranchs Feed on them and somehow store the nematocysts in their body and use them for their own defense. rtebrates-animals/other-invertebrates/nudibranch/

20 Hydrozoans Hydroids Colonial and share food
Very small and usually inconspicuous Some are sessile and some are motile.

21 Jellyfish Class Scyphozoan or true jellies
Swim by pulsating their bodies or floating in the currents (making them plankton). Sense organs= photoreceptors allow them to determine if it is dark or light. Many species do not like bright sunlight so they only come to the surface when its cloudy or near dusk.

22 Anthozoa Benthic Flower animals (bright colors)- sea anemones, corals, gorgonians (soft corals) Adults= sessile Only polyp stage


24 Sea Anemones Polyps Compartmentalized gastrovascular cavity
Deepwater / shallow Sessile- some bury themselves in the mud like tube anemones

25 Sea Anemones Continue Expand tentacles to feed
Contract their bodies when they are disturbed Change locations by gliding on their base, by crawling on their side, or walking on their tentacles. Some species can detach and swim with brief contractions.

26 Nutrition / Digestion / Feeding
Digest their prey in the central gastrovascular cavity Two way digestive tract- food goes in and comes out the same way. Digestion and excretion are through the same crevice. Sessile- suspension feeders / filter feeders (plankton and organic matter) such as corals and anemones. Carnivorous- feed mostly on fish and larger invertebrates. Prey is paralyzed by the toxin in the nematocyst. Upside down jelly-> Cassiopeia, feeds on plankton that gets stuck in mucus produced by modified tentacles.

27 Cassiopeia

28 Ecological Roles Provide habitats like corals
Key predators of the ocean Coral polyps: extremely important. They provide habitat for thousands of other organisms. The reefs provide a solid surface for sessile marine animals to attach to, place of refuge for fish, and they act as a buffer to protect coastal organisms from waves and storms.




32 Host Symbionts Portuguese Man of War and the Nomeus (man of war fish). Fish just swims amongst the tentacles without getting stung while gaining protection from the jelly, but it also lures other fish into the tentacles .




36 Host symbionts continues
Zoozanthellae lives in corals and provides food to the coral as well as other reef fish. Parrotfishes- eat large amounts of coral polyps.

37 Sea Anemones Clownfishes Cleaner Shrimp Snapping Shrimp Arrow Crabs
Brittle Stars Young anemones will attach to crabs as a form of camouflage.

38 Arrow Crab

39 Clownfish

40 Cleaner Shrimp

41 Snapping Shrimp

42 Ctenophora- The Comb Jellies (100-150 species known)
No stinging cells Hermaphroditic- release sperm and eggs into the water. Planktonic , iridescent during the day and bioluminescent at night. Eight rows of cilia plates for locomotion, the plates beat allowing the animal to move. Carnivorous-> eats zooplankton, larval fish, and fish eggs. Ecological Role-> managing zooplankton size, regulation of fish species, and they channel nutrients to other species that eat them.

43 Ctenophore videos




47 Phylum Mollusca Snails, slugs, oysters, clams, octopuses, squid, cuttlefish Four Main Body Parts: 1. Head- foot= head, mouth, sensory organs, and foot used for locomotion. 2. Visceral mass= circulatory, digestive, respiratory, excretory, and reproductive systems. 3. Radula- ribbon of tissue that contains teeth (bivalves don’t have these). Unique to mollusks and helps in scraping, piercing, tearing, or cutting food. 4. Mantle- protective tissue that covers all of the soft parts. Also responsible for forming the animals shell by excreting calcium. Also used for gas exchange in some species.




51 More Characteristics!!!! Soft body enclosed in a calcium carbonate shell that is secreted by the mantle. Shell can be modified-> squid= internal, octopus = none, snails = coiled. Hemolymph- bathes / floods the organs, no vessels. Complicated digestive system with a mouth in the head and the anus emptying into the mantle cavity.

52 Characteristics Continue….
Complex nervous system (Cephalopoda has the most) Gas exchange= gills, lungs, or through the body via diffusion. Hermaphroditic and internal fertilization (separate sexes). Shell is comprised of three layers: 1. Periostracum= outermost layer /proteins 2. Prismatic layer= middle layer / bulk of the shell and is made of calcium carbonate and protein 3. Nacreous layer= innermost layer / thin, crystal prismatic sheets of calcium carbonate.

53 As the animal grows, new periostracum and prismatic layers form in the mantle. The nacreous layer is secreted continuously and is responsible for the thickness of the shell and cause the shell to have a prism look to it. Pearls are formed in oysters when the nacreous material is layered over sand grains and other particles.

54 Class Polyplacophora- Chitons
Flattened bodies with eight shell plates Have a large flat foot that allows them to attach to rocks. When removed they roll into a ball for protection. Feed on algae with their radula

55 Class Scaphopoda- Tusk Shells
Shell resembles an elephants tusk Shell is open at both ends, and the animals foot protrudes from the larger end. Water enters and exits at the small end. Special tentacles on their head for feeding.

56 Class Gastropoda Means “Stomach Foot”
Snails, slugs, abalone, nudibranchs, etc Asymmetrical Coiled mass or organs is enclosed by the dorsal shell which rests on the central foot. Some retract back into their shells by closing the opening or aperture with a hard covering called the operculum.

57 Some are carnivores and feed on clams, oysters, worms, and small fish (whelks and cone snails). Whelks can locate a food source as far as 30 meters ( 99 feet) away, but it takes days to get there. Deposit feeders – feed on bottom sediment(mud snails)

58 Nudibranchs -> no shell, but they have colorful branches that represent the gut and exposed gills. They eat sponges and other inverts (cnidarians). Protect themselves by toxins. (add in at bottom) Nudibranchs have projections all over their bodies that serve as areas of gas exchange called cerata (since they lack gills). When they feed on Cnidarians they don’t digest the stinging cells, instead they leave the cells intact and move them along ciliated tracts in the digestive system that are then transferred to the cerata. Remember bright colors = don’t mess with me 

59 http://ngm. nationalgeographic

60 Internal fertilization-> most males have a long flexible penis that allows them to deposit sperm into or near the female’s genital opening. Egg cases of the female are usually surrounded by a jelly-like sac or a hard case (like a whelk egg case). Some do shed their eggs into the sea = trochophore (free swimming larva).

61 Class Bivalvia- Bivalves!!!
Clams, mussels, oysters, scallops Two valve shell Umbo = oldest part of the shell near the hinge. Inhalant and exhalant openings / siphons -> obtain oxygen and also filter and sort food and waste particles. Adductor muscles= large muscles that close the valves. Foot function= burrowing and locomotion Inhalant = carries food and oxygen, Exhalant= removes waste.

62 More about Bivalves………….
Clams use their foot to burrow into the sand and then use a siphon to draw water in and out which allows them to breath and eat while under the sand.

63 Palps-> after the food is filtered through the gills, it forms a mass of paired structures that move the food to the bivalves mouth where it enters the digestive system.

64 Bivalve adaptations Different habitats but most are infauna = living beneath the sand. Mussels byssal threads allow them to attach to rocks. Pearls form when oysters secrete shiny layers of calcium carbonate to coat irritating particles that are loaded in the mantle and inner surface of the shell= nacreous layer. Scallops-> swim by rapidly ejecting water (jet propulsion) from the mantle cavity and clapping the valves together using its adductor muscles. Largest = geoduck (3 feet in length)

65 Mussels Byssal Threads

66 Geoduck

67 Scallops

68 Class Cephalopoda Octopuses, Squid, Cuttlefish, and Nautilus (only one covered in a shell) Reduction or loss of external shell “Head-footed”-> head pushes down toward the foot Complex Nervous system Foot= modified into arms and tentacles and equipped with suckers for catching prey. Large eyes-> set on the sides of their head and can see shaped and colors Thick muscular mantle = protection Mantle forms a mantle cavity behind the head where 2-4 gills are located Water enters at the free end of the mantle and leaves through the siphon. Swim by forcing water out of the mantle cavity through the siphon= jet propulsion. Siphon can move in any direction.

69 Reproduction in Bivalves (add in)
Separate sexes Sperm and eggs are shed into the water and fertilization takes place in the water column. Some are hermaphroditic like scallops and oysters. Some oyster species brood the eggs in their gills and then suck in the sperm for fertilization.















84 Octopuses!!!!!!!!!! Not octopi! Eight arms No shell
Crabs, lobsters, and shrimp= favs!!! Yummy  Bite prey using beak like jaws and the radula helps clean away the flesh. Then they secrete a paralyzing substance, most are harmless Live in crevices, bottles, rocks, corals Distract predators with their ink sac, which produces a dark cloud of fluid. Highly developed tactile sense and can discriminate objects in the basis of touch.

85 Dwarf Octopus 2 inches long!!!

86 Pacific Giant Octopus- 30 feet (9 m.)

87 Squid Elongated body and covered by mantle with two triangular fins
Can change directions because they have a siphon Eight arms, two tentacles, which all have suckers that circle the mouth Shell= pen = embedded in the mantle

88 Cuttlefish Resemble squids in having eight arms and two tentacles
Flattened body Fins run along the sides of the body Have a calcified inner shell that allows them to be buoyant- the shell is the cuttlebone and is sold as a calcium source for birds in pet shops. Swim over the bottom and feed on invertebrates such as crabs and shrimp

89 Nautilus- add in Coiled external shell
Series of gas filled chambers that allows it to maintain buoyancy Has short sucker like tentacles that are used to capture prey. Scavenger and feeds on benthic organisms such as hermit crabs

90 All Cephalopods – add in
All swim by jet propulsion via their siphon Communicate by moving their arms, bodies, and changing color. Specialized pigment cells called chromatophores Pigment cells are dispersed = darker Pigment cells are concentrated = lighter

91 The Mimic Octopus Changes shape and color to mimic other organisms.

92 Feeding and Nutrition of Cephalopods
Carnivores Locate prey with their eyes and tentacles The beak bites and tears prey

93 Reproduction in Cephalopods
Separate sexes Mating involves courtship displays. Male squids have a modified arm that takes their sperm (spermatophore) and places it into the mantle cavity of the female (oviduct). Some species lay eggs in shells, while others attach their eggs to rocks or objects. Octopuses- lay eggs and incubate them until they hatch, while pumping water over them continuously so that they stay oxygenated. The mothers die afterwards because she eats little to nothing the whole time. She invests everything into her offspring.

94 Arthropods- animals with jointed appendages
Phylum Arthropoda- crabs, sea spiders, lobsters, horseshoe crabs, hermit crabs, etc. Most successful group of animals, 75% of all animal species. Hard exoskeleton, jointed appendages, and sophisticated sense organs make it successful!

95 Exoskeleton-> hard, protective skeleton (on the outside)
Made of thin chitin (proteins and sugars) Calcium salts provide strength Flexible- easy movement Muscles attach to it- efficient movement Drawbacks-> exoskeleton does not grow with animal, they molt, make them soft and susceptible to predators.

96 Body of Arthropods Segmented with jointed appendages
Function in locomotion Efficient feeding Sensory structures for monitoring the environment Body ornamentation -> to attract a mate or for camouflage.

97 Nervous System Highly developed
Sense organs allow them to move quickly when environment changes Capable of learning

98 Subphylum- Chelicerates-> spiders, ticks, scorpions, horseshoe crabs, sea spiders
Six pairs of appendages Chelicerae- one pair, and is modified for the purpose of feeding and takes the place of mouthparts.

99 Horseshoe Crabs Class- Xiphosura
Live in shallow waters, bays, estuaries Living fossils and have not changed much 3 basic body regions = entire body is carapace Cephalothorax- largest, obvious appendages Abdomen- gills are located Telson- long spike, used for steering and defense Carapace- hard outer covering

100 More Horseshoe Crabs Movement-> walking and swimming
Feeding-> worms, mollusks, algae Pick up food with chelicerae and pass it to the walking legs which crush the food before passing it to the mouth.

101 H. Crabs Males are smaller
Mating season-> one male or many males will attach to the carapace of a female and then they come to shore during high tide to mate and the female digs up the sand with the front of her carapace, depositing eggs in the depression. The male rides on the females back, shed his sperm onto the eggs before they are covered. Pedipalp-> large set of claws on the males that help the males attach / grab onto the females shell.


103 Subphylum Crustacea Decapods, mantis shrimp, krill, copepods, amphipods, and barnacles Mandibulates-> paired appendages on the head called mandibles (modified for feeding). 3 Main body regions: Head, thorax, and abdomen

104 Sensory antennae Walking legs that are modified for swimming- also known as swimmerets. Chelipeds are used for reproduction and defense Small ones exchange gas through the body and large ones have gills. The gills are feathery structures beneath the carapace. Molting-> hide away because they are vulnerable. They hide until a new exoskeleton has hardened initiated by hormones in the head caused by changes in environmental conditions (temperature and photoperiod). Mandible and maxillae are used for feeding

105 Pistol Shrimp


107 Order Decapoda Crabs, lobsters, true shrimp
10 feet (five pairs of walking legs) First pair= chelipeds= pincers used for capturing prey and for defense. Largest is the giant spider crab (4 m and 40 pounds)


109 Specialized behaviors
Hermit Crabs- jump from shell to shell to accommodate body size Decorator Crabs- attach bits of sponges and anemones to carapace for camouflage Blue Crabs- most powerful and agile swimmers, last pair of legs are like paddles= propellers.

110 Hermit Crabs

111 Decorator Crabs

112 Blue Crabs

113 Nutrition and Digestion
Chelipeds= capture prey Mandibles= crush food Plates in stomachs = grind food further Alaskan King Crab-> sea stars and bivalves Snowcrabs-> polycheates, crustaceans, bivalves Hermit Crabs-> shrimp-> scavengers, detritus Fiddler Crabs-> deposit feeders (scoop up mud) filter out organic matter and spit out mineral residue into round pellets. Filter feeders-> mole crabs, porcelain crabs, pea crabs, burrowing shrimp

114 Reproduction Usually separate sexes / internal fertilization
Males have special appendages for clasping the female and sperm delivery They transmit sperm in packets= spermatophores Brood their eggs into chambers Shrimp-> shed their eggs into the water

115 Mantis Shrimp The second pair of thoracic appendages is enlarged and has a moveable finger that can be extended rapidly to capture prey / defense-> smash or smear prey (blows can break an aquarium)

116 Krill Pelagic Shrimp Filter Feeders
Bioluminescent photophores attract mates in swarms. Main diet of whales, seals, penguins, fish (blue whales eat a ton of krill in one feeding) Literally jump out of their skins to molt

117 Amphipods Bodies to resemble shrimp
Burrowers live in tubes that they build Appendages are used for jumping, burrowing, or swimming. Beach flea

118 Copepods Largest group of small crustaceans
The most abundant zooplankton Feed on phytoplankton and detritus (filter feeders)

119 Barnacles Sessile- only crustacean to be  Class- Cirripedia
Attach to animals, rocks, boats, shells, corals, and any other solid object in the ocean

120 Echinoderms Echinodermata-> means spiny skinned animals
Sea stars, sea urchins, sea cucumbers, Radial symmetry Benthic- lives on the bottom

121 Structure Endoskeleton- spiny covering, internal structure. Below epidermis is composed of calcium carbonate plates (ossicles) that project up = spiny skin Pedicellarie- tiny, pincers at the base of the spines that project up= spiny skin (clean body and free of parasites) Water vascular system – hydraulic system that functions in locomotion, feeding, gas exchange, and excretion.

122 Structure Continues Madreporite= water enters
Tube feet= hollow with ampulla (saclike structure) Ambulacral groove- the sucker at the end of the ampulla

123 Class Asteroidea- Sea Stars
Central disk with five arms Mouth= underside From each mouth radiates the ambulacral groove with tiny tube feet. Aboral surface is rough / spiny and is on the opposite the mouth.


125 Movement Water is pumped into the tube feet from the ampullae which cause them to protect the ambulacral groove. The suckers then hold firmly to solid surfaces while the muscles in the tube feet contract which forces water back in the ampullae and causing the tube feet to shorten. Very slow process.

126 Feeding Carnivores or scavengers Eat fish and invertebrates
Locates prey chemically by kind of “smelling” the substances released by the prey Mussels and bivalves- wrap around prey and pries the valves open Sea Star- spits out a portion of its stomach out of its mouth and inserts it into the bivalves mouth and digests the prey. Also releases enzymes to breakdown the food and then retracts back.

127 Reproduction and Regeneration
Fragmentation- a piece breaks off as long as the gonads are in tact it can produce another Some can produce a whole new species as long as part of the central disc is present. Some species are capable of sexual reproduction

128 Class Ophiuroids Brittle Stars, basket stars, serpent stars
Benthic organisms Five arms-> slender / distinct Lack pedicellarie (pincers) Ambulacral grooves are closed Tube feet are used to feeding and locomotion, no suckers Avoid light Burrowers

129 Ophiuroids Brittle stars -> get their name because they detach one or more arms when disturbed-> arm undulates wildly distracting predators, while the brittle stars move away-> regenerate

130 Feeding Carnivores, scavengers, deposit feeders, suspension feeders, filter feeders Brittle-> filter feeders and deposit feeders (eat organic matter on the bottom) Filter- lift arm in the air and wave it -> releases strands of mucus that form around all of the arms= net= traps plankton Basket stars= suspension feeders= zooplankton -> climb up corals at night and fan their arms toward the current -> coil the arms around it.

131 Reproduction Cast off or automize (predators) Divide in half
Hermaphrodites External / Internal fertilization

132 Class Echinoidea Means like a “hedgehog”
Sea urchins, heart urchins, sand dollars Enclosed body by a hard endoskeleton called a test Benthic Rocks / bury Regular Echinoids-> sea urchins with long removable spines. Bilateral irregular Echinoids-> heart urchins and sand dollars. They bury in the sand and the test is small spined (locomotion / cleaning)



135 Echinoid Structure Tube feet project from five pairs of ambulacral areas that are derived from the same embryonic structures as the arms of sea stars, spines from test Spines function in protection Sexes are separate, external fertilization

136 Feeding Most are grazers scraping the surface with their teeth
Sea urchin-> five teeth called Aristotle's lantern Sand dollars and heart urchins -> tube feet to pick up food Lift posterior half of its body projecting above the sand.

137 Class Holothuroidea Sea cucumbers Elongated bodies
Body wall is leathery Move slowly using ventral tube feet and muscle contractions Gas exchange- tubules called respiratory trees Sexes are separate Some brood their eggs in body cavity and larvae leaves via the anus


139 Feeding Deposit or suspension feeders
Around the mouth they have tentacles that they trap food with. The tentacles are coated with a sticky mucus, so the organisms just get stuck on them and they retract their tentacles back into their mouth.

140 Behavior When disturbed some species release Cuverian tubules from their anus that looks like spaghetti. When it touches sea water it becomes sticky. Eviscerate, which means they release some of their internal organs through either the mouth or anus.

141 Crinoids- Class Crinoida
Sea lilies, feather stars Most primitive of Echinoderms, they are aged back to the Paleozoic era (80 species) Free moving -> swim and crawl for short distances / escape Cling to the bottom using a cirri Nocturnal (shallow water) Crawl out of tight spaces its time to feed Suspension feeders-> filter small organisms with tube feet and by mucous nets of the ambulacral grooves (zooplankton / detritus) Regeneration, external fertilization Separate sexes


143 What are Echinoderms ecological role?
Provide food for humans -> we eat the gonads of sea urchins / sea cucumbers They are predators of molluscs, other echinoderms, cnidarians, crustaceans, and kelp. Sea cucumbers= medicinal. They produce a poison called holothurin which suppresses tumor growth and can aid in muscle and nerve problems. Sea urchin roe (ovaries with eggs) sells to Japan for per pound= sushi Sea urchins destroy kelp beds and lobster pots Control algae growth, especially on coral reefs.

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