Cnidarian Study Guide Vocabulary 1. _________Cnidocytes______________________________: Stinging cells that contain poison to paralyze prey 2. _________Gastrodermis______________________________________: The inner germ layer 3. _________Polyp______________________________________: A cnidarian body plan with tentacles pointed up and a thin mesoglea 4. __________Bioluminescent_____________________________________: Glow in the dark 5. __________Mesoglea_____________________________________: Jelly-­‐like portion between the two cell layers that provides support for the cnidarian. 6. __________Gastrovascular cavity______________________________: Hollow gut with a single opening 7. __________Epidermis_____________________________________: The outer germ layer 8. __________Medusa_____________________________________: A cnidarian body plan with tentacles pointed down and a thick mesoglea 9. __________Nematocyst_____________________________________: Coiled harpoon-­‐like stinger that shoots out of the stinging cells 10. __________Planula_____________________________________: The larva stage of a cnidarian 11. __________Tentacles_____________________________________: Arm-­‐like projections on a cnidarian’s body 12. ___________Cnidaria____________________________________: What is the phylum we’re talking about? 13. ___________Diploblastic____________________________________: Having two tissue layers 14. ___________Portuguese man-­‐of-­‐war____________________________________: A colonial hydrozoan with a gas filled air float and long, stinging tentacles Classification of Cnidarians **Make sure you can match the class to the examples** 15. Kingdom _______Animalia______________________________________ 16. Phylum Cnidaria a. Class Anthozoa i. Examples: ______Sea anemone___________________ and _____coral________________________ b. Class _____Scyphozoa__________________________________ i. Example: Jellyfish c. Class ______Hydrozoa_________________________________ i. Example: Hydras d. Class Cubozoa i. Example: Box jellyfish Fill in the Blank 17. What are the defense structures in cnidarians? _____Cnidocytes______________________________________ 18. What is the outer cell layer in a cnidarian? ______Epidermis__________________________________________ 19. What is the inner cell layer in a cnidarian? ______Gastrodermis__________________________________________ 20. How many tissue/cell layers do cnidarians have? _____2___________________________________ 21. What type of symmetry do most cnidarians have? ____Radial___________________________________ 22. Which class of cnidarians lives only in freshwater? _____Hydrozoa_________________________________ 23. Which body form do jellyfish have (polyp or medusa)? ___Medusa________________________________ 24. Which body form do sea anemones, corals, and hydras have (polyp or medusa)? ___Polyp___________________________ 25. Which phylum are comb jellies in? ______Ctenophora__________________________________________ 26. How many species are in Phylum Cnidaria? _____9,000_________________________________ 27. How many species are in Phylum Ctenophora? ____100______________________________ 28. What do ALL cnidarians have in common…i.e. why do we group animals into this phylum? All cnidarians have tentacles that can STING…animals in other phyla that have tentacles cannot sting with them (i.e. octopus, squid) 29. Why are comb jellies in a separate phylum? They have tentacles, but their tentacles have sticky mucus to catch prey rather than stingers. 30. Be able to describe how cnidarians feed—structures that help them get food, how they take food in, how they digest food. They sting prey, which usually paralyzes it. They use the tentacles to pull the food into the mouth. From there, food enters the gastrovascular cavity where it gets digested. 31. Label the following organisms with: Polyp or medusa Label the following organisms with: Gastrodermis, Epidermis, Mesoglea Two Main Body Plans of
Cnidarians
UPRIGHT TENTACLES
TENTACLES HANG DOWN
epidermis
Polyp
mouth
mesoglea
gastrodermis
Medusa
Mesoglea THICK
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Mesoglea THIN
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32. Label the figure with: planula, egg, sperm, zygote, female medusa, and male medusa Obelia Life Cycle (Hydrozoan)
Larva called a planula
reproductive
polyp
male medusa
female medusa
ovum
sperm
zygote
feeding
polyp
polyp
forming
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planula
Fig. 25-15a, p.411
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