Good Afternoon!

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Good Afternoon!

• On a sheet of paper (it can be a half sheet) tell
  me 5 things that you remember about Jellyfish
  from the movie on Friday!
• You will be turning this in 5 minutes after the
  bell rings ?

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Invertebrates

• Phylum
• Cnidaria

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Cnidarians

• Phylum Cnidaria
• Includes jellyfish, anemones, corals, sea pens
• Next level of complexity after sponges
• Tissues are specialized to perform specific
• functions.
• Also called coelenterates
• This term is not used
• often anymore!

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Coelenterates

• Even though not used often anymore
• Refers to 2 Phylums combined
• Phylum Cnidaria Phylum Ctenophora
• Ctenophora Comb Jellies
• Cnidaria Jellyfish, Sea anemones, Corals, Sea
  pens
• Have a hollow body cavity, very
• simple tissue organization

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Cnidarians

• Have NO bones
• Have NO heart
• Have NO brain
• Have NO real eyes
• Have NO respiratory system

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Cnidarians Body Plan

• Display radial symmetry, which is a
• regular arrangement of similar body parts
  around a central axis.
• Look the same from all sides
• Have no head, front, or back

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Cnidarians Body Plan

• Have an oral surface where the mouth is an
  aboral surface on the opposite side.

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• Occur as 2 basic forms
• Polyp A sac-like attached stage (sessile)
• Medusa Bell-like stage
• Some experience both forms during their life
  time, and others spend their entire lives as one
  of the two forms.

Medusa
Polyp
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Cnidarians Anatomy

• Have a centrally located mouth surrounded by
• tentacles which are slender, finger like
• extensions.
• Use tentacles to catch handle food

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Cnidarians Anatomy

• The mouth opens into a gut (enteron) where food
  is digested.
• - The gut has only one opening, the mouth.

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Cnidarians Anatomy

• The mesoglea is extremely thick, has a
• jelly like consistency makes up the
• largest portion of the animal
• This is how jellyfish got their name.

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How Cnidarians Sting

• At the narrow outer edge of the cnidocyte is a
  short trigger hair called a cnidocil (trigger).

Upon contact with prey, the contents of the
nematocyst are explosively discharged, firing a
dart-like thread containing neurotoxins.
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How Cnidarians Sting

• These stinging cells contain poison arrows
  connected to threads called nematocyts.
• Cnidarians can still sting when they are dead!!

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Tentacles

• They capture small prey by discharging their
  cnidocytes (stinging cells), which are unique
  structures found on the tentacles.

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Tentacles

• The tentacle then brings the victim to the mouth
  to be digested.
• The food passes through the body cells, and the
  waste must go back out of the mouth.

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Jellyfish Eating
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Jellyfish Feeding Video Clip
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Cnidarians Anatomy

• 2 Layers of cells form the body wall
• - Ectoderm external layer
• - Endoderm internal layer that lines the gut

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Feeding

• Zooplankton Drifting microscopic animals

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Feeding

• Phytoplankton Drifting microscopic plants.

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Feeding

• After paralyzing its prey, a cnidarian pulls the
  prey through its mouth and into its
  gastrovascular cavity.
• Gastrovascular Cavity A digestive chamber with
  one opening.
• Food enters waste leaves the body through
• that opening.

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Response to Environment

• Cnidarians gather information from their
  environment using specialized sensory cells.
• Both polyps medusas have a nerve net.
• Nerve Net A loosely organized network of nerve
  cells that together allow cnidarians to detect
  stimuli such as the touch of a foreign object.

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Response to the Environment

• Cnidarians have statocysts which are groups of
  sensory cells that help determine the direction
  of gravity.
• Ocelli are eyespots made of cells that detect
  light.

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Movement

• Hydrostatic Skeleton consists of a layer of
  circular muscles a layer of longitudinal
  muscles that together with the water in the
  gastrovascular cavity, enable the cnidarian to
  move.
• Medusas move by jet propulsion.
• Muscle contractions cause the bell-shaped body to
  close like a folding umbrella.
• This action pushes water out of the bell, moving
  the medusa forward.

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Cnidaria Reproduction

• Some reproduce asexually by budding (in polyps)
• Some reproduce sexually by releasing gametes.
• Some sexual forms are monoecious and others are
  dioecious
• Eggs and sperm are released into the stomach and
  then through the mouth into the sea.

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Cnidaria Reproduction

• In some cases, to reproduce, a male releases his
  sperm into the surrounding water (spawn).
• The sperm then swims into the mouth of the female
  jellyfish, allowing the fertilization of the ova.
  

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Cnidarian Reproduction

• In other cases, sexual reproduction takes place
  with external fertilization in water
• External Fertilization Takes place outside the
  body.
• The male female releases eggs
• and sperm at the same time.

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Jellyfish Review Video Clip
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Class Hydrozoan

• Types of Cnidarians

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Types of Cnidarians Hydrozoans

• Class Hydrozoans
• Hydra
• They can be found in most unpolluted fresh-water
  ponds, lakes, and streams
• They are usually a few millimeters long and are
  best studied with a microscope
• Hydra has a tubular body secured by a simple
  adhesive foot called the basal disc.

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Types of Cnidarians Hydrozoans

• Class Hydrozoans
• Hydra
• At the free end of the body is a mouth opening
  surrounded by one to twelve thin, mobile
  tentacles.
• Hydras are generally sedentary
• or sessile, but can move,
• especially when hunting.

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Types of Cnidarians Hydrozoans

• Hydra
• They move by bending over and attaching
  themselves to the substrate with the mouth and
  tentacles then release the basal disc.
• The body then bends over and makes a new place of
  attachment with the foot.
• They inch-worm or
• somersault to move

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Types of Cnidarians Hydrozoans

• Class Hydrozoans
• Portuguese man-of-war
• Consist of feather or bushy colonies of polyps.
• - Some polyps are specialized floats, which
• may be gas-filled
• - Other polyps form the long tentacles used to
• capture prey.

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Types of Cnidarians Hydrozoans

• Portuguese Man-of-War

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Class Scyphozoans

• Types of Cnidarians

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Types of Cnidarians Scyphozoans

• Class Scyphozoan
• Includes jellyfish
• Have a rounded body, or bell.
• Swim w/ rhythmic contractions of the bell, but
  swimming ability is limited are carried by
  ocean currents.

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Class Scyphozoans

• 95 of body is made of water
• Here before dinosaurs and sharks
• Inhabit all oceans of the world

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Moon Jellyfish also called Common Jellyfish
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Moon Jellyfish Life Cycle
Planula

• Each jellyfish is either male or female
• 1. Males release sperm into surrounding water
• 2. Eggs get suck in pits on the oral arms, and
  are fertilized by sperm
• 3. The egg develops into a planula
• Planula is the larval stage, small, covered in
  cilia
• 4. The planula settles on a hard surface
  develops into a polyp to become sessile

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Moon Jellyfish Life Cycle

• 5. The polyp begins reproducing asexually by
  budding, and now called a scyphistoma
• 6. Budding produces miniature medusae called
  ephyrae
• 7. After ephyrae are released, they gradually
  grow into adult forms

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Jellyfish Reproduction
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Class Scyphozoans Importance

• Jellies are considered a delicacy by many
  people.
• Low in fat calories
• Rich in nutrients.
• Others claim they taste like rubber bands.

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Class Scyphozoans Importance

• Food source for fish, sea turtles, and other
  organisms

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Looks like a Jellyfish to sea, but isnt!
Clear plastics (such as bags and balloons) are
often mistaken for jellyfish by animals such as
the endangered leatherback sea turtle. When they
eat plastic, these animals will often starve to
death as the plastic clogs their intestines and
they can no longer digest food.
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Recycle Plastic Bags Make sure they do not
find their way into the ocean!
Save the Sea Turtles!
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Class Cubozoans

• Some are among the most dangerous marine animals.
• Sea wasp, also known as the box jellyfish, of
  Australia Southeast Asia
• Extreme pain immediately when touched by
  tentacles
• Within minutes, heart failure may occur

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Class Anthozoan

• Types of Cnidarians

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Types of Cnidarians Anthozoans

• Class Anthozoan
• Includes sea anemones corals
• Solitary or colonial polyps
• Lack medusa stage
• Have more advanced gut contains several thin
  partitions called septa that provide extra
  surface area for digestion of larger prey.

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Coral Spawning
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Types of Anthozoans

• Sea Anemones Large muscular polyps.

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Sea Anemone Importance Provides Homes

• Clownfish are protected from the anemones
  stinging cells by their mucus. They catch food
  and feed the anemone. Eggs are laid near or under
  the anemone and tended and protected by the male
  clownfish.

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Types of Anthozoans/Corals

• Stony Corals
• - Calcium carbonate skeletons that form coral
• reefs
• - More common in tropics

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What do Corals Need to Survive?

• 1. Good Water Quality
• Low turbidity (cloudiness or haziness of water)
• Temperature at least 68 F
• 2. Sunlight
• Algae that lives inside corals must have sunlight
• This is why corals do not live in deep water
• 3. Zooplankton
• Corals eat zooplankton
• 4. Water Movement
• Access to food
• Flushes sediments off the coral
• so they can access sunlight

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Coral Reef Video Clip
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Types of Anthozoans/Corals

• Gargonians
• - Sea fans
• - Secrete a branching skeleton made of proteins.

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Corals
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Zooxanthellae Video Clip
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Mutualism in Anthozoans/Corals

• Mutualism A relationship between two species
  that benefits both members. The association is
  necessary to both species.
• Corals Zooxanthellae are mutualistic
• Zooxanthellae an algae
• -- Live in the tissues of coral polyps
• -- All reef building corals have them
• -- Helps corals synthesize (make) calcium
  carbonate

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Why Coral Reefs are Important

• 1. Protect from soil erosion Waves from the
  ocean crash onto the shore and over time erode
  the shoreline.
• Coral reefs that border land act as a buffer
  for the
• harsh waves.
• The reefs cause the waves to slow down or
  stop
• them completely.
• This prevents erosion of the shoreline and
  potential
• property damage.

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Why Coral Reefs are Important

• 2. Breeding Grounds Shelter Some species
  that do not even live in the reef may travel to
  that reef just to breed.
• Coral reefs are very important for
  replenishing fish
• populations that people consume.

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Why Coral Reefs are Important

• 3. Tourism Fisheries They are important for
  fisheries tourism businesses. Restaurants,
  hotels, SCUBA rentals, boat rentals, tour guides,
  air travel, cruise lines, and many more
  industries profit from healthy coral reefs.

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Coral Atolls

• Atolls are coral islands.
• The center of the atoll is a shallow lagoon.
• Formed when a volcanic islands middle sank into
  the
• ocean, and left a ring of land
• The island bit of the atoll is a narrow ring of
  land around the lagoon, with coral reefs all
  around the outside of the island.

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Ecology

• Crown of Thrones Starfish Well known for its
  voracious appetite for live hard-corals.
• One explanation for local population explosions
  of these destructive starfish is the collection
  of this starfish's natural enemy, the Triton
  Trumpet
• Many scuba clubs organize "starfish hunts" in
  which these starfish are rounded up in an effort
  to save reefs from destruction.

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Ecology Coral Bleaching

• The whitening of coral colonies is due to the
  loss of symbiotic zooxanthellae from the tissues
  of polyps.
• Pollution, temperatures, disease are being
  blamed for corals losing their zooxanthelle.

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Stings from Cnidarians

• Symptoms
• Includes corals, jellies, sea anemones
• Painful raised lesions in lines
• Muscle spasms may develop
• Raised lesions may fill with puss
• May cause nausea, vomiting, dizziness,
• headaches, irregular heart rate

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Stings from Cnidarians

• Treatment
• Remove any tentacles (ex stick)
• Lift off skin, dont scrape off
• -- Dont use fingers, tentacles can still sting
• Rinse with sea water to wash away
• nematocysts left on skin
• Rinse with vinegar neutralizes nematocysts
• -- If there is no vinegar, then urine will work

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Stings from Cnidarians

• Treatment Continued
• Can apply Hydrocortisone is redness persists
• Seek medical attention if muscle spasms
• develop
• -- Doctor will give you calcium gluconate in
  IV

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Death by Cnidarians

• Stings are usually mild
• Some stings are fatal
• Box jellyfish -- Mortality rate of about 20
  in
• 1st 3 minutes of a
  sting
• There isnt an international data base for
  mortalities by jellyfish stings exact numbers
  of deaths are unknown.

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Phylum Ctenophora

• Look like Cnidarians, but are classified in a
  different phylum

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Phylum Ctenophora

• Includes comb jellies

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Phylum Ctenophora

• Have 8 rows of cilia bands, called comb rows, for
  locomotion
• As they swim, the comb rows diffract light to
  produce a shimmering, rainbow effect.

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Phylum Ctenophora

• Have colloblasts on tentacles used to capture
  prey are adhesive cells that stick to prey
• Lack nematocysts
• Eat zooplankton only

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The End