contentshydrozoascyphozoaanthozoactenophoracnidaria phyla cnidaria and ctenophora radial or biradial...

ContentsHydrozoaScyphozoaAnthozoaCtenophora Cnidaria

Phyla Cnidaria and Ctenophora

Radial or biradial symmetry


Contents• Phylum Cnidaria

Unique characteristics Systems

• 1 (Integumentary, skeletal, muscle and digestive) • 2 (Excretory, respiratory, circulatory and nervous)• 3 (Endocrine and reproductive)

Taxonomy

• Phylum Ctenophora Unique characteristics Comparison to Cnidaria Taxonomy


Phylum Cnidaria

• Some unique characteristics Nematocysts

Alternation of generations

• (polyp and medusa body forms)

Planula larva

Mesoglea


Cnidaria Systems 1

• IntegumentaryIntegumentary One cell layer (epidermis)

• SkeletalSkeletal Hydrostatic or some with endoskeletons and/or

exoskeleton of calcium carbonate (Anthozoa)

• MuscleMuscle None; epith-muscle cells (fibers from cells into

mesoglea) Anthozoa may have muscles

• DigestiveDigestive Incomplete


Cnidaria Systems 2

• ExcretoryExcretory Isotonic in marine; some freshwater forms use

contractile vacuoles)

• RespiratoryRespiratory No system , use cellular diffusion

• CirculatoryCirculatory No system, use cellular diffusion and mesoglea

• NervousNervous Nerve net (ring around the bell of medusa)


Cnidaria Systems 3

• EndocrineEndocrine Have hormones, secreted by nervous system

• ReproductiveReproductive Alternation of generations, vary as to dominant stage

• Medusa is the sexual body plan

• Polyp is the asexual body plan

Planula larva

Dioecious or monoecious


Cnidaria Taxonomy

• Class Hydrozoa (hi-dro-zo-

ah) Hydra, Obelia, Gonionemus, Physalia

• Class Scyphozoa (sky-fo-zo-

ah) Aurelia

• Class Anthozoa (an-tho-zo-

ah) Metridium Tubipora Gorgonia Other anthozoan coral

• Class Cubozoa (ku-bo-zo-

ah) No specimens


Class Hydrozoa

• Alternation of generation with polyp as the dominant body plan

• Incomplete digestive with an unbranched gut.

• Mesoglea thin

• Medusa with a velum


Class HydrozoaGenus— Hydra

CS through hydra


Class HydrozoaGenus— Obelia


Class HydrozoaGenus— Gonionemus


Class HydrozoaGenus— Physalia


Class Scyphozoa

• Alternation of generation with medusa the dominant body plan

• Incomplete digestive with four branches

• Mesoglea thick with some cells

• Medusa without velum


Class ScyphozoaGenus— Aurelia


Class Anthozoa

• No alternation of generation - polyps only

• Incomplete digestive with 6 to 8 branches (septia)

• Nematocyst in the gut (acontia)

• Mesoglea thick and with muscle tissue

• Coral Reefs


Class AnthozoaGenus — Metridium


Class AnthozoaGenus — Tubipora


Class AnthozoaGenus — Gorgonia

Sea fan

String coral


Other Anthozoan Coral

AstrangiaFungia

Sea pansyLettuce coral

Brain coral


Coral Reefs

• Fringing reef Close to land mass none or a narrow lagoon between

land and shore.

• Barrier reef Has a wide and deep lagoon between reef and shore

line.

• Atolls Reefs that encircle a lagoon, but there is no island


Phylum Ctenophora

• Unique Characteristics Comb plates

Medusa only

Luminescence common

Position of paired tentacles changes

symmetry to biradial


Comparison Ctenophora to Ctenophora

• Differences No alternation of

generations (medusa only)

No nematocysts Biradial symmetry,

two tentacles Combs Complete digestive

system May be triploblastin

• Similarities Aboral-oral axis Nerve net Lack of organ systems


Taxonomy Phylum Ctenophora

• Class Tentaculata (ten-tack-u-la-ta) Pleurobrachia


End of presentation

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