Created for use with BIO 2215 Oklahoma City Community College Phylum Cnidaria Moore High School Zoology Adapted by: Tamara Lookabaugh Created for use with BIO 2215 Oklahoma City Community College Dennis Anderson

Background Information 9000 Species 700 Million Years Old Symbiosis with Algae, Coral use them to gain nutrition and build reefs Cnidocytes containing Nematocysts to capture prey 4 Classes – Hydrozoa, Scyphozoa, Anthozoa, Cubozoa

Phylum Cnidaria Marine, Few Freshwater Radial symmetry with oral and aboral ends Two body forms Polyp vs. Medusa One opening into and out of gastrovascular cavity. Cnidocytes on tentacles, epidermis and internal Ocelli and Statocysts Sexual and Asexual Nerve net Diffusion to breathe and release waste Carnivores, filter feeders

Radial symmetry Hydra Polyp looking over the top

Mouth and Tentacles

Fig. 13.2 Two Basic body Forms Fig. 13.2

Body Forms Polyp form Medusa form Body is tube with tentacles Aboral end attached by pedal disc Anthozoans only have this form Medusa form Bell or umbrella shaped Tetramerous-arranged in fours Some species have both body forms, medusa is considered the adult, polyp is juvenile Scyphozoans are mostly medusa form

Cnidocyte Structure and Nematocyst Discharge Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cnidocyte Structure and Nematocyst Discharge

Stinging Structure Cnidocytes produce and hold the stinging structure called NEMATOCYSTS. Cnidocil – hair-like trigger Operculum – door or flap to hold in harpoon Nematocysts – coiled up harpoon like structure (some have toxin and are barbs) Discharge is caused by: High Osmotic pressure, brushing against Cnidocil by prey 40,000x acceleration of gravity, 5 g’s

Generalized Cnidarian Life Cycle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Generalized Cnidarian Life Cycle

Nervous System Nerve cells, arranged in a nerve net.

Cladogram of Cnidaria Anthozoa Scyphozoa Cubozoa Medusa cuboidal Loss of medusa Hydrozoa Polyp stage reduced Septa divide gastrovascular cavity Radial symmetry, cnidocytes, planula larva

Class Hydrozoa Means “Water Serpent or Animal” Cnidocytes present only on epidermis. Most have Polyp and Medusa stage. Most are marine and colonial. Asexual reproduction by budding. Sexual reproduction via gametes produced by epidermis & released into water. Monoecious

Class Hydrozoa Example Organisms: Hydra (movement) - Freshwater Pedal laceration, can tumble, climb, walk Obelia form and life cycle Gonionemus (different views) Physalia (video national geographic) (Portuguese Man O War – open ocean)

Budding Asexual cycle Sexual cycle Class Hydrozoa Hydra Encapsulated embryo Ovaries Budding Spermaries Sexual cycle Asexual cycle Sperm and Egg unite from sperm and egg factories

Obelia Hydranth with Gastrozooid “Feeding Polyp”

Obelia Medusae Medusa bud Gonangium

Obelia Fig. 13.9

Class Hydrozoa Gonionemus Fig. 13.12b

Class Hydrozoa Gonionemus Velum

Class Hydrozoa Physalia “Portuguese man-o-war”

Class Scyphozoa Means “Cup Animal” Largest Jellyfish Tentacles can reach 70 meters – Open Ocean Umbrellas have indentations with rhopalium & lappet containing sense organs – ocelli & statocysts Manubrium(mouth) surrounded by 4 oral arms

Class Scyphozoa Aurelia- “Moon Jelly”

Strobilation Aurelia Life History Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Aurelia Life History Strobilation

Scyphozoa are Dioecious Fig. 13.18 Fig. 13.18

Planula Larva Ciliated larva than can swim to a new location Larva of Scyphozoa are Created by sperm from one Male ephyrae that releases Sperm on female ephyrae Medusa arm and meets an Egg to form a zygote which Become a planula.

Aurelia Oral arm Gastric pouch Mouth Tentacles

Class Anthozoa Means “flower animal” Medusa stage absent Solitary or colonial Some produce protective skeletons Tentacles around mouth working with siphinoglyph creating water currents Cnidocytes internal ejected out Anemones glide, pedal laceration All Marine Protandrous, mono and dioecious

Class Anthozoa Sea Anemone

Class Anthozoa Metridium Tentacles Mouth Pharynx Septum Gastrovascular cavity

Symbiosis

Class Anthozoa Corals Protective skeleton of calcium carbonate Polyp retracts when not feeding Hexacorallia Found in warm tropical seas

Class Anthozoa - Zooxanthellae Photosynthetic dinoflagellates (brown) Live in corals Provide nutrients for coral by photosynthesis Mutualism

Class Anthozoa - Corals Colony of interconnected polyps Important recyclers of phosphorus and waste materials Greatest diversity of all the marine life in the oceans

Class Anthozoa Meandrina Brain Coral (coral spawning link)

Class Anthozoa Gorgonia Sea Fan

Class Anthozoa Tubipora Pipe Organ Coral

Class Anthozoa Actinodiscus Mushroom Coral

Class Anthozoa Acropora Staghorn Coral

Coral Reefs Formed over thousands of years from successive layers of coral skeleton deposits (calcium carbonate forms underwater mountains of coral animal skeletons) The underwater equivalent of the amazon jungle- very high species diversity and biomass Reefs contain sponges, colonial hydrozoans, anemones, many varieties of coral, fish, many types of worms we’ve not discussed, not to mention bryozoans, ctenophores, protists, bacteria, etc etc..

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coral Reef Ecosystem Photo © McGraw-Hill Higher Education, Barry Barker, Photographer

Types of Reefs Fringing Reef – Near land with no lagoon Barrier Reef – Parallel to land with wide and deep lagoon Atoll – Encircles a lagoon with a steep bank Bank Reef – Greater distance from land Largest Reef in the world is the Great Barrier Reef 1200 miles around the coast of Australia.

Fringing Reef

Barrier Reef

Atoll

Bank Reef

Class Cubozoa- all are dangerous Means “cube animal” Box jellies Tentacles arise at four corners from blade-like pendalium. All marine Strong swimmers which prey primarily on fish voracious eaters Stings of some may be fatal within minutes to humans.

Class Cubozoa Gonad Pedalium Tentacle

Class Cubozoa Chironex fleckeri Sea Wasp Also known as “THE HAND OF DEATH”

Chironex and Irukandji Video on Chironex fleckeri Video on Irukandji stings

The End