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25 Cards in this Set
- Front
- Back
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What are the four main classes of cnidaria?
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Hydrazoa, Schyphozoa, Cubozoa, Anthozoa.
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What types of animals are in the class of hydrazoa?
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Man-of-war, Hydra, Obelia, some corals. All marine, with a dominant polyp stage.
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What types of animals are in the class Schyphozoa?
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Common jellyfish. All marine animals with with a dominant medusa stage.
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What types of animals are in the class Cubozoa?
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Box jellies and sea wasps, most dangerous jellies, dominant medusa stage.
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What type of animals are in the class Anthozoa?
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Sea anemones, sea fans, some corals. No medusa stage. usually radially symmetrical.
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What are the three layers of the cnidarian polyp?
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Outer epidermis layer from ectoderm, Inner gastrodermis layer from endoderm, and middle mesoglea that is a space-filling layer. This has cells, and no particular tissue.
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Describe the structure of a polyp.
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A sac with a mouth and hollow tentacles. Individual cells can flex and use hydrostatics for their skeletal support.
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What is the difference between a polyp and a medusa?
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Medusa isn't attached to a surface and has a thick layer of mesoglea.
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What is a nematocyt?
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The organelle within a cell that contains coiled barbs.
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What is a cnidocyte?
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The cell which contains the nematocyst.
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How does a nematocyst work?
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Contains long, coiled barbs that are flipped to inward. These are released by pressure in the capsule and everts to the outside when triggered by touch or chemical means.
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What is polymorhpism?
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When an organism exists in many different forms.
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What is dimorphism?
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When an organism exists in two different forms. e.g.hydra, anemone -- polyp
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Briefly describe the life cycle of the obelia.
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Asexually buds of from polyp-->sexually reproduces--> releases sperm/egg-->zygote-->blastula-->free swimming attaches to substrate --> polyp that feeds, grows into a colony of polyps--> repeats.
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What are the three layers of the hydra tissues?
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Gastrodermis, epidermis, mesoglea.
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Describe the class Hydrozoa.
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dominant polyp form, has velum, most live in marine waters, but some in freshwater. Man-o-war, Obelia, etc.
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Describe the obelian lifecycle.
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Gonagium develope medusa, which bud off and produce sperm and eggs, they are fertilized and turn into planula larvae, which burrow to become obelia colonies.
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What are pelagic hydrozoans?
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large marine cnidarians that float near the surface of the water.
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Describe the class Schyphozoa.
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Dominant medusa form, lack velum, typically marine. Jellyfish.
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What is the budding process in Schyphozoans?
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Strobilation.
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Describe the class Cubozoa.
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Tropical and subtropical areas, potent neurotoxins, and dominant medusa stage. Include box jellies.
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Describe the class Anthozoa.
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Only exist in polyp stage, all are marine, and have two classes: octocorallia and hexacorallia.
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Describe members of the subclass Octocorallia.
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From Anthozoa -- have radial octamerous symmetery, exotic cnidarians are included, like "sea pens," "sea pansies," and "horny corals"
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Describe members of the subclass Hexacorallia.
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Hexamerous symmetry, from anthozoa, include stony corals and sea anemonies.
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What type of exoskeleton do stony corals have?
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calcareous exoskeleton.
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