Phylum CnidariaPhylum CnidariaAll contain nematocysts-All contain nematocysts-

stinging structuresstinging structures

CnidariansCnidarians Jellies, Anemones, CoralsJellies, Anemones, Corals DimorphismDimorphism: Two body shapes during : Two body shapes during

life cycle. (life cycle. (Polyp & MedusaPolyp & Medusa)) Gastrovascular cavityGastrovascular cavity (digestive) (digestive) CarnivoresCarnivores Primitive Primitive nerve netnerve net Two distinct tissue layers: Two distinct tissue layers: Epidermis & Epidermis &

GastrodermisGastrodermis CnidocyteCnidocyte (Stinging cells) in tentacles (Stinging cells) in tentacles Radial SymmetryRadial Symmetry

Epidermis

Mesoglea

Gastroderm

Mesoglea

Gastrovascular cavity

Mouth/anus

Tentacles

Tentacles

Mouth/anus

Gastrovascularcavity

Polyp Medusa

 The Polyp and Medusa Stages

FeedingFeeding

Paralyze prey and pulls into Paralyze prey and pulls into mouthmouthgastrovascular cavitygastrovascular cavity

Undigested materials passed out Undigested materials passed out through through mouth/anusmouth/anus

Respiration, Circulation, Respiration, Circulation, ExcretionExcretion

Diffusion through body wallsDiffusion through body walls

Nerve netNerve net-network of nerve cells to -network of nerve cells to detect stimulidetect stimuli

StatocystsStatocysts to determine gravity direction to determine gravity direction OcelliOcelli as eyespots to detect light as eyespots to detect light

Response

MovementMovement Hydrostatic skeletonHydrostatic skeleton-muscles w/ -muscles w/

water enable movementwater enable movement

Body contracts to force water out, moving jellyfish in opposite direction.

Reproduction and Life Reproduction and Life cyclecycle

Most cnidarians Most cnidarians reproduce both reproduce both sexually and sexually and asexually.asexually.

External External fertilizationfertilization

Fertilization occurs in the open water, producing many diploid zygotes.

Sperm (N)

Egg (N)

Haploid

Diploid

FERTILIZATION

MEIOSIS

Male medusa(2N)

Zygote (2N)

Polyp

Buddingpolyp

Youngmedusa

Female medusa(2N)

Each zygote grows into a ciliated larva. The larva eventually attaches to a hard surface and develops into a polyp.

Swimming larva

The polypbuds to release young medusas.

Adult medusas reproduce sexually by releasing gametes intothe water.

Jellyfish Life Cycle

Classes of CnidariaClasses of Cnidaria HydrozoaHydrozoa (Serpent Animals) (Serpent Animals) ScyphozoaScyphozoa (Cup Animals) (Cup Animals) AnthozoaAnthozoa (Flower Animals) (Flower Animals)

Class HydrozoaClass Hydrozoa Both body forms: Both body forms:

polyp and medusapolyp and medusa Reproduce Reproduce

sexually as sexually as medusas.medusas.

Example: Example: Portuguese Man Of Portuguese Man Of WarWar

Class ScyphozoaClass Scyphozoa

True jelliesTrue jellies Medusa form during Medusa form during

most of its life cycle.most of its life cycle. Lions Mane is the Lions Mane is the

most common in most common in L.I.S.L.I.S.

Butter fish lives in Butter fish lives in its tentacles.its tentacles.

Moon JellyMoon Jelly

Free swimmingFree swimming Up to 30 cm wideUp to 30 cm wide Found in intertidal Found in intertidal

zone zone Found in L.I.S. Found in L.I.S.

(Also in the tanks (Also in the tanks of Maritime of Maritime Aquarium)Aquarium)

Sea Wasp Sea Wasp (another (another scyphozoan ex.)scyphozoan ex.)

Known as box Known as box jellyfishjellyfish

Most powerful Most powerful venom in the worldvenom in the world

Lives in AustraliaLives in Australia Can be up to 60 Can be up to 60

meters in lengthmeters in length

Class AnthozoaClass Anthozoa They are individual They are individual

or colonies of or colonies of polyps found in polyps found in coastal waters.coastal waters.

No medusa stage.No medusa stage. Examples: Sea Examples: Sea

anemones,Hard anemones,Hard corals, sea fanscorals, sea fans

Northern Red AnemoneNorthern Red Anemone

7.5 cm high, 12.5 7.5 cm high, 12.5 cm widecm wide

Attach to rocks Attach to rocks under rockweed.under rockweed.

Found in subtidal Found in subtidal zoneszones

Striped AnemoneStriped Anemone

2 cm high .5 cm 2 cm high .5 cm widewide

Found on lower Found on lower rocks on sheltered rocks on sheltered shores.shores.

Can tolerate Can tolerate reduced salinity.reduced salinity.

Sea fansSea fans

Hard coralsHard corals

Phylum CtenophoraPhylum Ctenophora Ctenophores Ctenophores Common name: Comb jelliesCommon name: Comb jellies Contain eight rows of comb plates made Contain eight rows of comb plates made

of cilia used for locomotion (of cilia used for locomotion (ciliary ciliary combscombs))

BioluminescentBioluminescent No stinging cellsNo stinging cells They feed on planktonThey feed on plankton

Comb JelliesComb Jellies