Jellies, Corals, and Anemones Chapter 7: CNIDARIANS: Jellies, Corals, and Anemones

Cnidarians Cnidarians are named because of the stinging cells they possess - cnidocytes Cnidocytes produce organelles called nematocysts that actually sting the prey

Cnidarians Cnidarians are radially symmetrical. Look the same from all sides and have no head, front, or back

Cnidarians have 2 ends: Oral Surface Aboral Surface

Anatomy & Physiology 2 tissue layers Intermediate “non-living” layer Serves as support system Single opening (mouth/anus) and no head

Cnidarians Cnidarians occur in 2 basic forms. Polyp form: attaches to the bottom sediments, the mouth opens upwardly and is surrounded by a ring of tentacles Medusa form: free-floating stage - commonly known as a jellyfish

Cnidarian: Classes 3 classes of cnidarians: Hydrozoans Scyphozoans Anthozoans

Cnidarian: Hydrozoan Hydrozoans: colonial organisms not true jellyfish. Can be drifting polyps or siphonophores Siphonophores like the Portuguese man-of-war are drifting colonies of polyps

Cnidarian: Scyphozoan “true” jellyfish have limited swimming abilities, so they depend on the currents Spend most of their life as a medusa

Schyphozoan - cannon ball jelly

Scyphozoan - moon jelly

Scyphozoan - Sea Nettle

Scyphozoan - Upside-down jelly

Scyphozoan - Lion’s Mane:

Anthozoans: Includes - sea anemones, corals, sea fans, sea pens, and sea pansies EXCLUSIVELY polyp form They can be very colorful - look like underwater flowers Most complex cnidarian

Anthozoan - continued They have strong muscles that allow them to extend and retract their tentacles - for feeding and avoidance of danger Often are symbiotic When two organisms create a union in which each is benefited by the other Over time the clownfish becomes immune to the sting of sea anemones, then uses the anemone for protection

Anthozoans - Corals Two types - hard and soft corals Hard corals secrete a calcium carbonate skeleton - which remains after death Soft corals do not produce the rigid skeleton and look more like plants than animals - sea fans and sea pens are two examples

Polyp Anatomy

Coral Nutrition Zooxanthellae provide nourishment for the coral through photosynthesis Coral has an immense surface area for feeding (the entire reef) Coral Reefs

Bartholomea annulata: Corkscrew Anemone Description: thin, droopy tentacles that spiral Distribution: Florida, Bahamas, Caribbean

Gorgonia ventalina: Common Sea Fan Description: single plane and fan shaped Purple, yellow, or brown Distribution Florida Keys near coral reefs

Pennatulacea: Common Sea Pen Description: Resemble quill pens, will glow when touched Distribution: Shallow and deep water from polar waters to tropics

Renilla: Sea Pansy Description: Flattened, kidney-shaped Distribution: Pacific and Atlantic coasts of North America

Montastrea annularis: Boulder Start Coral Description: Form dome-like tops Large mounds Shades of green, brown, yellow, and gray Distribution: Western Atlantic Ocean

Sponge and Cnidarian Video http://youtu.be/DuQcmpHZ9tQ

Coral Reefs Economy Types Tourism Fishing Research Fringing Barrier Atoll

Ecology Marine and Freshwater (Hydrozoa) All oceans, all depths Symbiants Shelter and food

Phylum Ctenophora (comb jellies) Have eight rows of cilia on their outer body - used in locomotion They do not have stinging cells!!! They catch food by trapping it a sticky coating on their cilia or sucking in mouthfuls of water

COMB JELLY