InvertebratesInvertebrates Phylum Phylum CnidariaCnidaria

CnidariansCnidarians Phylum Phylum CnidariaCnidaria

Includes jellyfish, anemones, corals, & sea pensIncludes jellyfish, anemones, corals, & sea pens

Next level of complexity after spongesNext level of complexity after sponges

Tissues are specialized to perform specific Tissues are specialized to perform specific functions.functions.

Also called Also called coelenteratescoelenterates This term is not used This term is not used often anymore!often anymore!

CoelenteratesCoelenteratesEven though not used often anymore…Even though not used often anymore…

Refers to 2 Phylums combined: Refers to 2 Phylums combined:

Phylum Phylum CnidariaCnidaria & Phylum & Phylum CtenophoraCtenophora

- CtenophoraCtenophora: : Comb JelliesComb Jellies

- CnidariaCnidaria: : Jellyfish, Sea anemones, Corals, & Sea pensJellyfish, Sea anemones, Corals, & Sea pens

• Have a hollow body cavity, & very Have a hollow body cavity, & very

simple tissue organizationsimple tissue organization

CnidariansCnidarians

Have NO bonesHave NO bones

Have NO heartHave NO heart

Have NO brainHave NO brain

Have NO “real” eyesHave NO “real” eyes

Have NO respiratory systemHave NO respiratory system

Cnidarians: Body PlanCnidarians: Body Plan Display Display radial symmetryradial symmetry, which is a , which is a regular arrangement of similar body regular arrangement of similar body

parts around a central axis.parts around a central axis.

Look the same from all sidesLook the same from all sides Have no head, front, or backHave no head, front, or back

Cnidarians: Body PlanCnidarians: Body PlanHave an Have an oraloral surfacesurface where the mouth is where the mouth is

& an & an aboralaboral surfacesurface on the opposite on the opposite side.side.

Occur as 2 basic forms:Occur as 2 basic forms:

PolypPolyp: A sac-like attached stage (sessile): A sac-like attached stage (sessile)

MedusaMedusa: Bell-like stage: Bell-like stage

Some experience both forms during their life time, and Some experience both forms during their life time, and others spend their entire lives as one of the two forms.others spend their entire lives as one of the two forms.

Polyp Medusa

Cnidarians: AnatomyCnidarians: Anatomy Have a centrally located mouth surrounded by Have a centrally located mouth surrounded by tentaclestentacles which are slender, finger like which are slender, finger like extensions.extensions.

Use tentacles to catch & handle foodUse tentacles to catch & handle food

Cnidarians: AnatomyCnidarians: AnatomyThe mouth opens into a The mouth opens into a gutgut (enteron) (enteron)

where food is digested.where food is digested.

- The gut has only one opening, the - The gut has only one opening, the mouth.mouth.

Cnidarians: AnatomyCnidarians: Anatomy The The mesogleamesoglea is extremely thick, has a is extremely thick, has a

jelly like consistency & makes up the jelly like consistency & makes up the

largest portion of the animallargest portion of the animal

This is how jellyfish got their name.This is how jellyfish got their name.

TentaclesTentaclesThey capture small prey by discharging They capture small prey by discharging

their their cnidocytescnidocytes (stinging cells), which (stinging cells), which are unique structures found on the are unique structures found on the tentacles. tentacles.

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.

How Cnidarians StingHow Cnidarians StingThese stinging cells contain poison arrows These stinging cells contain poison arrows

connected to threads called connected to threads called nematocytsnematocyts..

* Cnidarians can still sting when they are dead!!* Cnidarians can still sting when they are dead!!

TentaclesTentacles The tentacle then brings the victim to the The tentacle then brings the victim to the

mouth to be digested.mouth to be digested.

The food passes through the body cells, and The food passes through the body cells, and the waste must go back out of the mouth.the waste must go back out of the mouth.

Jellyfish EatingJellyfish Eating

Jellyfish Feeding Video ClipJellyfish Feeding Video Clip

Cnidarians: AnatomyCnidarians: Anatomy 2 Layers of cells form the body wall2 Layers of cells form the body wall

- - EctodermEctoderm: external layer: external layer

- - EndodermEndoderm: internal layer that lines the gut: internal layer that lines the gut

FeedingFeedingZooplanktonZooplankton: Drifting microscopic animals: Drifting microscopic animals

FeedingFeeding

PhytoplanktonPhytoplankton: Drifting microscopic plants.: Drifting microscopic plants.

FeedingFeeding

After paralyzing its prey, a cnidarian pulls the After paralyzing its prey, a cnidarian pulls the prey through its mouth and into its prey through its mouth and into its gastrovacular cavity.gastrovacular cavity.

Gastrovascular CavityGastrovascular Cavity: A digestive : A digestive chamber with one opening.chamber with one opening.

Food enters & waste leaves the body through Food enters & waste leaves the body through

that opening.that opening.

Response to EnvironmentResponse to Environment

Cnidarians gather information from their Cnidarians gather information from their environment using specialized sensory cells.environment using specialized sensory cells.

Both polyps & medusas have a nerve net.Both polyps & medusas have a nerve net.

Nerve NetNerve Net: A loosely organized network of : A loosely organized network of nerve cells that together allow cnidarians to nerve cells that together allow cnidarians to detect stimuli such as the touch of a foreign detect stimuli such as the touch of a foreign object.object.

Response to the EnvironmentResponse to the Environment Cnidarians have Cnidarians have statocystsstatocysts which are which are

groups of sensory cells that help determine the groups of sensory cells that help determine the direction of gravity.direction of gravity.

OcelliOcelli are eyespots made of cells that detect are eyespots made of cells that detect light.light.

MovementMovement

Hydrostatic SkeletonHydrostatic Skeleton: consists of a layer of : consists of a layer of circular muscles & a layer of longitudinal muscles that circular muscles & a layer of longitudinal muscles that together with the water in the gastrovascular cavity, together with the water in the gastrovascular cavity, enable the cnidarian to move.enable the cnidarian to move.

• Medusas move by jet propulsion.Medusas move by jet propulsion.

• Muscle contractions cause the bell-shaped body to Muscle contractions cause the bell-shaped body to close like a folding umbrella. close like a folding umbrella.

• This action pushes water out of the bell, moving the This action pushes water out of the bell, moving the medusa forward.medusa forward.

Cnidaria ReproductionCnidaria Reproduction

Some reproduce Some reproduce asexuallyasexually by budding by budding (in polyps)(in polyps)

Some reproduce Some reproduce sexuallysexually by releasing gametes. by releasing gametes.

Some sexual forms are Some sexual forms are monoeciousmonoecious and and others are others are dioeciousdioecious

Eggs and sperm are released into the stomach Eggs and sperm are released into the stomach and then through the mouth into the sea. and then through the mouth into the sea.

Cnidaria ReproductionCnidaria Reproduction

In some cases, to reproduce, a male releases In some cases, to reproduce, a male releases his sperm into the surrounding water (spawn). his sperm into the surrounding water (spawn).

The sperm then swims into the mouth of the The sperm then swims into the mouth of the female jellyfish, allowing the fertilization of the female jellyfish, allowing the fertilization of the ova.ova.

Cnidarian ReproductionCnidarian Reproduction In other cases, sexual reproduction takes place In other cases, sexual reproduction takes place

with external fertilization in water: with external fertilization in water:

External FertilizationExternal Fertilization: Takes place outside : Takes place outside the body.the body.

The male & female releases eggs The male & female releases eggs

and sperm at the same time.and sperm at the same time.

Jellyfish Review Video ClipJellyfish Review Video Clip

Class HydrozoaClass Hydrozoa

Types of CnidariansTypes of Cnidarians

Types of Cnidarians: HydrozoansTypes of Cnidarians: Hydrozoans

Class Class HydrozoaHydrozoa

HydraHydra- They can be found in most unpolluted fresh-They can be found in most unpolluted fresh-

water ponds, lakes, and streamswater 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.

Types of Cnidarians: HydrozoansTypes of Cnidarians: Hydrozoans

Class Class HydrozoansHydrozoans

HydraHydra- 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.

Types of Cnidarians: HydrozoansTypes of Cnidarians: Hydrozoans

HydraHydra- 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

Types of Cnidarians: HydrozoansTypes of Cnidarians: Hydrozoans

Class Class HydrozoaHydrozoa

Portuguese man-of-warPortuguese man-of-war

Consist of feather or bushy Consist of feather or bushy coloniescolonies of polyps. of polyps.

- Some polyps are specialized floats, which - Some polyps are specialized floats, which

may be gas-filled may be gas-filled

- Other polyps form the long tentacles used to- Other polyps form the long tentacles used to

capture prey.capture prey.

Types of Cnidarians: HydrozoansTypes of Cnidarians: Hydrozoans

Portuguese Man-of-WarPortuguese Man-of-War

Class ScyphozoaClass Scyphozoa

Types of CnidariaTypes of Cnidaria

Types of Cnidarians: ScyphozoansTypes of Cnidarians: Scyphozoans

Class Class ScyphozoanScyphozoan Includes jellyfishIncludes jellyfishHave a rounded body, or Have a rounded body, or bellbell..

Swim w/ rhythmic contractions of the bell, but Swim w/ rhythmic contractions of the bell, but swimming ability is limited & are carried by swimming ability is limited & are carried by ocean currents.ocean currents.

Class Class ScyphozoansScyphozoans

95% of body is made of water95% of body is made of water

Here before dinosaurs and sharksHere before dinosaurs and sharks

Inhabit all oceans of the worldInhabit all oceans of the world

Moon JellyfishMoon Jellyfish also called also called Common JellyfishCommon Jellyfish

Moon JellyfishMoon Jellyfish Life Cycle Life Cycle

- Each jellyfish is either male or femaleEach jellyfish is either male or female

1. Males release sperm into surrounding water1. Males release sperm into surrounding water

2. Eggs get suck in pits on the oral arms, and are 2. Eggs get suck in pits on the oral arms, and are fertilized by spermfertilized by sperm

3. The egg develops into a planula3. The egg develops into a planula PlanulaPlanula is the larval stage, small, & covered in cilia is the larval stage, small, & covered in cilia

4. The planula settles on a hard surface & develops into 4. The planula settles on a hard surface & develops into a polyp to become sessilea polyp to become sessile

Planula

Moon Jellyfish Life CycleMoon Jellyfish Life Cycle5. The polyp begins reproducing asexually by budding, 5. The polyp begins reproducing asexually by budding,

and now called a and now called a scyphistomascyphistoma

6. Budding produces miniature medusae called 6. Budding produces miniature medusae called ephyraeephyrae

7. After ephyrae are released, they gradually grow into 7. After ephyrae are released, they gradually grow into adult formsadult forms

Jellyfish ReproductionJellyfish Reproduction

Class Scyphozoans: Class Scyphozoans: ImportanceImportance

* Jellies are considered a delicacy by many * Jellies are considered a delicacy by many people. people.

* Low in fat & calories* Low in fat & calories

* Rich in nutrients. * Rich in nutrients.

* Others claim they taste like rubber bands.* Others claim they taste like rubber bands.

Class Scyphozoans: Class Scyphozoans: ImportanceImportance

* * Food source for fish, sea turtles, and other Food source for fish, sea turtles, and other organismsorganisms

Looks like a Jellyfish to sea, but isn’t!Looks like a Jellyfish to sea, but isn’t!

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.

Recycle Plastic BagsRecycle Plastic Bags& Make sure they do not find their way into the ocean!& Make sure they do not find their way into the ocean!

Save the Sea Turtles!

Class CubozoansClass CubozoansSome are among the most dangerous marine Some are among the most dangerous marine

animals.animals.

* Sea wasp, also known as the * Sea wasp, also known as the box jellyfishbox jellyfish, of , of Australia & Southeast AsiaAustralia & Southeast Asia

- Extreme pain immediately when touched by tentaclesExtreme pain immediately when touched by tentacles- Within minutes, heart failure may occurWithin minutes, heart failure may occur

Class AnthozoanClass Anthozoan

Types of CnidariansTypes of Cnidarians

Types of Cnidarians: AnthozoansTypes of Cnidarians: AnthozoansClass Class AnthozoanAnthozoan

Includes sea anemones & coralsIncludes sea anemones & corals

Solitary or colonial polypsSolitary or colonial polyps

Lack medusa stageLack medusa stage

Have more advanced gut – contains several Have more advanced gut – contains several thin partitions called thin partitions called septasepta that provide extra that provide extra surface area for digestion of larger prey.surface area for digestion of larger prey.

Coral SpawningCoral Spawning

Types of AnthozoansTypes of AnthozoansSea AnemonesSea Anemones: Large muscular polyps.: Large muscular polyps.

Sea Anemone Importance: Sea Anemone Importance: Provides HomesProvides Homes

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

Types of Anthozoans/CoralsTypes of Anthozoans/Corals

Stony CoralsStony Corals: :

- Calcium carbonate skeletons that form coral - Calcium carbonate skeletons that form coral

reefsreefs

- More common in tropics- More common in tropics

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

Coral Reef Video ClipCoral Reef Video Clip

Types of Anthozoans/CoralsTypes of Anthozoans/Corals GargoniansGargonians: :

- Sea fans- Sea fans

- - Secrete a branching skeleton made of proteins.Secrete a branching skeleton made of proteins.

CoralsCorals

Zooxanthellae Video ClipZooxanthellae Video Clip

Mutualism in Anthozoans/CoralsMutualism in Anthozoans/Corals

MutualismMutualism: A relationship between two species that : A relationship between two species that benefits both members. The association is necessary benefits both members. The association is necessary to both species. to both species.

Corals & Zooxanthellae are mutualisticCorals & Zooxanthellae are mutualistic

ZooxanthellaeZooxanthellae: an algae: an algae

-- Live in the tissues of coral polyps-- Live in the tissues of coral polyps

-- All reef building corals have them-- All reef building corals have them

-- Helps corals synthesize (make) calcium carbonate-- Helps corals synthesize (make) calcium carbonate

Why Coral Reefs are ImportantWhy Coral Reefs are Important1. Protect from soil erosionProtect 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.

Why Coral Reefs are ImportantWhy Coral Reefs are Important

2. Breeding Grounds & ShelterBreeding 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.

Why Coral Reefs are ImportantWhy 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.

Coral Coral AtollsAtolls

AtollsAtolls are coral islands. are coral islands.

The center of the atoll is a shallow lagoon.The center of the atoll is a shallow lagoon.

Formed when a volcanic island’s middle sank into the Formed when a volcanic island’s middle sank into the ocean, and left a ring of landocean, and left a ring of land

The island bit of the atoll is a narrow ring of land The island bit of the atoll is a narrow ring of land around the lagoon, with coral reefs all around the around the lagoon, with coral reefs all around the outside of the island. outside of the island.

EcologyEcology

Crown of Thrones StarfishCrown of Thrones Starfish: Well known for its : Well known for its voracious appetite for live hard-corals. voracious appetite for live hard-corals.

One explanation for local population explosions of One explanation for local population explosions of these destructive starfish is the collection of this these destructive starfish is the collection of this starfish's natural enemy, the Triton Trumpet starfish's natural enemy, the Triton Trumpet

Many scuba clubs organize "starfish hunts" in which Many scuba clubs organize "starfish hunts" in which these starfish are rounded up in an effort to save reefs these starfish are rounded up in an effort to save reefs from destruction. from destruction.

Ecology: Ecology: Coral Bleaching Coral Bleaching

The whitening of coral colonies is due to the The whitening of coral colonies is due to the loss of symbiotic zooxanthellae from the tissues loss of symbiotic zooxanthellae from the tissues of polyps.of polyps.

Pollution, temperatures, & disease are being Pollution, temperatures, & disease are being blamed for corals loosing their zooxanthelle.blamed for corals loosing their zooxanthelle.

Stings from CnidariansStings from Cnidarians

SymptomsSymptoms

* Includes corals, jellies, & sea anemones* Includes corals, jellies, & sea anemones

* Painful raised lesions in lines* Painful raised lesions in lines

* Muscle spasms may develop* Muscle spasms may develop

* Raised lesions may fill with puss* Raised lesions may fill with puss

* May cause nausea, vomiting, dizziness, * May cause nausea, vomiting, dizziness,

headaches, irregular heart rateheadaches, irregular heart rate

Stings from CnidariansStings from CnidariansTreatmentTreatment

* Remove any tentacles (ex: stick) * Remove any tentacles (ex: stick)

– – Lift off skin, don’t scrape offLift off skin, don’t scrape off

-- Don’t use fingers, tentacles can still sting-- Don’t use fingers, tentacles can still sting

* Rinse with sea water to wash away * Rinse with sea water to wash away

nematocysts left on skinnematocysts left on skin

* Rinse with vinegar – neutralizes nematocysts* Rinse with vinegar – neutralizes nematocysts

-- If there is no vinegar, then urine will work-- If there is no vinegar, then urine will work

Stings from CnidariansStings from Cnidarians

Treatment ContinuedTreatment Continued

* Can apply Hydrocortisone is redness persists* Can apply Hydrocortisone is redness persists

* Seek medical attention if muscle spasms * Seek medical attention if muscle spasms

developdevelop

-- Doctor will give you calcium gluconate in IV -- Doctor will give you calcium gluconate in IV

Death by CnidariansDeath by Cnidarians• Stings are usually mildStings are usually mild

• Some stings are Some stings are fatalfatal

* Box jellyfish -- Mortality rate of about 20% in* Box jellyfish -- Mortality rate of about 20% in

11stst 3 minutes of a sting 3 minutes of a sting

There isn’t an international data base for mortalities by There isn’t an international data base for mortalities by jellyfish stings – exact numbers of deaths are jellyfish stings – exact numbers of deaths are unknown.unknown.

Phylum Phylum CtenophoraCtenophora

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

Phylum CtenophoraPhylum Ctenophora

Includes comb jelliesIncludes comb jellies

Phylum CtenophoraPhylum CtenophoraHave 8 rows of cilia bands, called Have 8 rows of cilia bands, called comb rowscomb rows, ,

for locomotionfor locomotion

As they swim, the comb rows diffract light to As they swim, the comb rows diffract light to produce a shimmering, rainbow effect. produce a shimmering, rainbow effect.

Phylum CtenophoraPhylum Ctenophora

Have Have colloblastscolloblasts on tentacles used to on tentacles used to capture prey – are adhesive cells that stick capture prey – are adhesive cells that stick to preyto prey

Lack nematocystsLack nematocysts

Eat zooplankton onlyEat zooplankton only

The End