Transcript Cnidarians!!!!!!!!!!!!!!

http://www.youtube.com/watch?v=aJUuo
tjE3u8
Jellyfish, Hydroids, Corals, & Sea
Anemones
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.
 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.
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.
 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.
http://www.youtube.com/watch?v=BpKK
GB-ivQo
http://science.howstuffworks.com/zoolog
y/jellyfish-videos-playlist.htm
 Box
Jellyfish- kills a person in minutes (3-
20)
• http://www.youtube.com/watch?v=uIf0kRpkQ_0
 Portuguese
Man of War
• http://www.youtube.com/watch?v=lem0RAVzVC
M
 Leatherbacks
use them as a toy to play
with and to eat!
• http://www.youtube.com/watch?v=Rap3mnq0_l
o

Feed on them and somehow store the
nematocysts in their body and use them for their
own defense.
• http://video.nationalgeographic.com/video/animals/inve
rtebrates-animals/other-invertebrates/nudibranch/
 Hydroids
 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.
 Benthic
 Flower
animals (bright colors)- sea
anemones, corals, gorgonians (soft
corals)
 Adults= sessile
 Only polyp stage
 Polyps
 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.
 Clownfishes
 Cleaner
Shrimp
 Snapping Shrimp
 Arrow Crabs
 Brittle Stars
 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.
 http://www.youtube.com/watch?v=G7W
T81ukHZE
 http://www.youtube.com/watch?v=icKB9
EfURhQ
 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.
 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.
 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.
 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
 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.
 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)
 https://www.youtube.com/watch?v=FYh2
zeAsRXY
 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 
http://ngm.nationalgeographic.com/2008
/06/nudibranchs/doubiletphotography#/10-tentacles-clear-714.jpg
https://www.youtube.com/watch?v=sHg5
36CII2M
 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)
http://www.youtube.com/watch?v=iZhQL
oYIbJ4
http://www.youtube.com/watch?v=QzT2L
5CsiA8
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.

 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.
 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.
2 inches
long!!!
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
 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
 https://www.youtube.com/watch?v=2x-8v1mxpR0
 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
 https://www.youtube.com/watch?v=hcyz
r3zJol4
 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
 Changes
shape and color to mimic other
organisms.
 https://www.youtube.com/watch?v=H8o
QBYw6xxc
 Carnivores
 Locate
prey with their eyes and tentacles
 The beak bites and tears prey
 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.
Phylum Arthropodacrabs, 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
 Efficient feeding
 Sensory structures for monitoring the
environment
 Body ornamentation -> to attract a mate
or for camouflage.
 Highly
developed
 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.
 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
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.
 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.
 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
 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
 http://www.youtube.com/wat
ch?v=eKPrGxB1Kzc
 http://www.youtube.com/wat
ch?v=KkY_mSwboMQ
 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)
https://www.youtube.com/watch?v=iahuZEvWH8
 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
https://www.youtube.com/watch?v=yMx
Y4c5SeIs
 Bodies
to resemble shrimp
 Burrowers live in tubes that they build
 Appendages are used for jumping,
burrowing, or swimming.
 Beach flea
 Largest
group of small crustaceans
 The most abundant zooplankton
 Feed on phytoplankton and detritus
(filter feeders)
 Sessile-
only crustacean to be 
 Class- Cirripedia
 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,
 Radial symmetry
 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
 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.
 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
 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
 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
 Hermaphrodites
 External / Internal fertilization
 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)
 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.
 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
 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
 Separate sexes


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.
