Cnidarians!!!!!!!!!!!!!!. http://www.youtube.com/watch?v=aJUuotjE3u8. Jellyfish, Hydroids, Corals, & Sea Anemones. Basic Information. Radial symmetry Contain organisms such as jellyfish, hydroids, corals, and sea anemones
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Jellyfish, Hydroids, Corals, & Sea Anemones
Contain organisms such as jellyfish, hydroids, corals, and sea anemones
Cnidocytes- stinging cells in their tentacles that are used for protection and killing prey.
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.
Colonial and share food
Very small and usually inconspicuous
Some are sessile and some are motile.
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.
Flower animals (bright colors)- sea anemones, corals, gorgonians (soft corals)
Only polyp stage
Compartmentalized gastrovascular cavity
Deepwater / shallow
Sessile- some bury themselves in the mud like tube anemones
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.
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.
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.
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 .
Zoozanthellae lives in corals and provides food to the coral as well as other reef fish.
Parrotfishes- eat large amounts of coral polyps.
Young anemones will attach to crabs as a form of camouflage.
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.
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.
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.
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
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.
Means “Stomach Foot”
Snails, slugs, abalone, nudibranchs, etc
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.
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)
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
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).
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.
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.
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.
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)
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.
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.
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.
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
Resemble squids in having eight arms and two tentacles
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
Coiled external shell
Series of gas filled chambers that allows it to maintain buoyancy
Has 60-90 short sucker like tentacles that are used to capture prey.
Scavenger and feeds on benthic organisms such as hermit crabs
Changes shape and color to mimic other organisms.
Locate prey with their eyes and tentacles
The beak bites and tears prey
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.
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!
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.
Segmented with jointed appendages
Function in locomotion
Sensory structures for monitoring the environment
Body ornamentation -> to attract a mate or for camouflage.
Sense organs allow them to move quickly when environment changes
Capable of learning
Six pairs of appendages
Chelicerae- one pair, and is modified for the purpose of feeding and takes the place of mouthparts.
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.
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
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)
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.
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
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
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)
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
Bodies to resemble shrimp
Burrowers live in tubes that they build
Appendages are used for jumping, burrowing, or swimming.
Largest group of small crustaceans
The most abundant zooplankton
Feed on phytoplankton and detritus (filter feeders)
Sessile- only crustacean to be
Attach to animals, rocks, boats, shells, corals, and any other solid object in the ocean
Echinodermata-> means spiny skinned animals
Sea stars, sea urchins, sea cucumbers,
Benthic- lives on the bottom
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.
Madreporite= water enters
Tube feet= hollow with ampulla (saclike structure)
Ambulacral groove- the sucker at the end of the ampulla
Central disk with five arms
From each mouth radiates the ambulacral groove with tiny tube feet.
Aboral surface is rough / spiny and is on the opposite the mouth.
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.
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.
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
Brittle Stars, basket stars, serpent stars
Five arms-> slender / distinct
Lack pedicellarie (pincers)
Ambulacral grooves are closed
Tube feet are used to feeding and locomotion, no suckers
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
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.
Cast off or automize (predators)
Divide in half
External / Internal fertilization
Means like a “hedgehog”
Sea urchins, heart urchins, sand dollars
Enclosed body by a hard endoskeleton called a test
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)
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
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.
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
Deposit or suspension feeders
Around the mouth they have 10-30 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.
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.
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
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 100-150 per pound= sushi
Sea urchins destroy kelp beds and lobster pots
Control algae growth, especially on coral reefs.