Phylum Cnidaria
Body structure
1 body opening, radial symmetry, 2 cell layers that form tissues
Class Scyphozoa
All jellyfish except the box jellies, medusa stage is the dominant body form
Class Cubozoa
All the box jellyfish, name comes from the boxlike form of the medusa shape, stings can be fatal to humans
Polyp
Body for of Cnidarians that consists of a tube shape with tentacles surrounding the mouth
Medusa
Body form that consists of an umbrella shape with tentacles hanging down with the mouth between the tentacles
Nematocysts
Capsule in the Cnidocytes that holds a coiled, threadlike tube containing poison and barbs that are discharged to capture prey or defend the cnidarian
Reproduction
External fertilization, consists of sexual and asexual reproduction
Corals
Live as colonies, secrete protective calcium carbonate shelters around their soft bodies, living portion of the reef is the thin, fragile layer growing on top of the shelters lefts by others
Sea anemones
Live as individual animals, form symbiotic relationship with some animals, like the clownfish
Nerve net
Nervouse system, sensory structures that conduct impulses to and from all parts of the body to respond to stimuli
Cnidaria
Phylum name for Cnidarians, means "stinging cells"
Class Anthozoa
Sea anemones and corals, ~6200 species, polyp is the dominant body form
Gastrovascular cavity
Space surrounded by the inner cell layer that functions as a gut, cells inside this area release enzymes to aid in digestion
Cnidocytes
Stinging cells located on the tentacles
Class Hydrozoa
~2700 species, have both polyp and medusa stages in the life cycle, most form colonies, include the Portuguese Man of War and hydra