1. Phylum Cnidaria jellyfish, hydras, sea anemones, coraljellyfish, hydras, sea anemones, coral

2. Cnidaria have cnidocytes (stinging cells) which contain a nematocyst (harpoon-like structure) for stinging and paralyzing prey – located on tentacleshave cnidocytes (stinging cells) which contain a nematocyst (harpoon-like structure) for stinging and paralyzing prey – located on tentacles barbs coiled nematocyst discharged nematocyst

3. Tentacle Nematocyst “Trigger” Cuticle of prey Thread discharges Thread (coiled) Cnidocyte Thread

4. Cnidaria Radial SymmetryRadial Symmetry

5. made up of two tissue layers – endoderm and ectoderm separated by mesogleamade up of two tissue layers – endoderm and ectoderm separated by mesoglea Have two body forms: polyp and medusaHave two body forms: polyp and medusa Polyp Mouth/anus Body stalk Tentacle Gastrovascular cavity Endoderm Mesoglea Ectoderm Tentacle Mouth/anus Medusa

6. –Some cnidarians alternate between the 2 body forms: polyp – sessile, usually perform asexual reproductionpolyp – sessile, usually perform asexual reproduction medusa – free floating, usually perform sexual reproductionmedusa – free floating, usually perform sexual reproduction

7. Feeding polyp Reproductive polyp Medusa bud Medusa ASEXUAL REPRODUCTION (BUDDING) Portion of a colony of polyps 1 mm Key Haploid (n) Diploid (2n) Gonad SEXUAL REPRODUCTION MEIOSIS FERTILIZATION Egg Sperm Zygote Planula (larva) Developing polyp Mature polyp

8. Class Hydrozoa – hydras, Obelia, and Portuguese Man-of-WarClass Hydrozoa – hydras, Obelia, and Portuguese Man-of-War –usually alternate between polyp and medusa stages Portuguese Man-of-War

9. Class Scyphozoa – true jellyfish – have medusa as their primary body formClass Scyphozoa – true jellyfish – have medusa as their primary body form Jellies

10. Class Anthozoa – exists only as polyps, sea anemones and coralClass Anthozoa – exists only as polyps, sea anemones and coral Sea anemone (class Anthozoa)

11. Class Cubozoa – “box jellies”, sea wasps, marine, box-shaped medusae, potent venomClass Cubozoa – “box jellies”, sea wasps, marine, box-shaped medusae, potent venom Sea wasp (class Cubozoa)

12. Reproduction asexual reproduction by budding sexual reproduction by producing sperm in testes and eggs (ova) in ovaries fertilized egg becomes a larva which develops into an adult

13. Digestion food is taken in and wastes are expelled through the same opening – mouth digestion and circulation occur in the gastrovascular cavity

14. Polyp Mouth/anus Body stalk Tentacle Gastrovascular cavity Endoderm Mesoglea Ectoderm Tentacle Mouth/anus Medusa

15. Cnidaria have nerve tissue for coordinated movementhave nerve tissue for coordinated movement tissue level of organizationtissue level of organization