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Parazoa and Radiata

Parazoa and Radiata. Sponges Cnidarians Ctenophores. Phylum Porifera: The Sponges. General Information. Mainly marine organisms; evolved from choanoflagellates May have algae or bacteria that give them color Larva are flagellated, adults considered sessile

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Parazoa and Radiata

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  1. Parazoa and Radiata Sponges Cnidarians Ctenophores

  2. Phylum Porifera: The Sponges

  3. General Information • Mainly marine organisms; evolved from choanoflagellates • May have algae or bacteria that give them color • Larva are flagellated, adults considered sessile • Many disease-fighting compounds holdfast

  4. Tube Sponges Encrusting Sponges

  5. Characteristics • Can reproduce sexually or asexually • Gas exchange and excretion - diffusion at individual cells • Supported by skeletal fibers: spicules or spongin • Simple animals made of few specialized cells; NOtissues • Asymmetrical • Body with ostia • Most are filter feeders / suspension feeders • 1 family is carnivorous

  6. Anatomy of a Sponge: • Osculum • Spongocoel • Choanocyte • Amoebocyte • Mesohyl

  7. Suspension Feeding & Gas Exchange

  8. Sponge Reproduction: • Asexual reproduction • Buds or gemmules • Sexually – most sponges are hermaphrodites • Cells become egg/sperm • Sperm released into water • Fertilization occurs in mesohyl (egg) • Zygote becomes flagellated larva that leaves in flow of water

  9. Phylum Cnidaria Jellyfish Box jelly Sea anemone Coral

  10. Main Characteristics • Diploblastic, radial symmetry • Cnidocytes with nematocysts concentrated in tentacles • Gastrovascular cavity with 1 opening • 2 layers separated by mesoglea • Gas exchange and excretion occur by diffusion

  11. Structure cont… • Nerve nets • Connect sensory cells to contractile cells • Sense organs around edge of body • Ex. photoreceptors • Contractile cells • Not true muscles • Act as hydrostatic skeleton

  12. Cnidarians come in 2 forms: • Medusa – tentacles down • Polyp – tentacles up Many alternate between medusa and polyp during life cycle

  13. Hydrozoa ScyphozoaCubozaAnthozoa 4 Classes of Cnidaria

  14. Cnidarians are Carnivores • Feed on fish, larva, comb jellies, other zooplankton • Sting prey with their tentacles • Mouth  gastrovascular cavity  mouth • Jellyfish.asf

  15. Many have symbiotic zooxanthellae Environmental issue: Coral Bleaching A word about corals:

  16. Interesting Facts… Portuguese Man-of-War • Colonial • Has sail-like float • Tentacles can grow up to 165 feet and are nearly invisible

  17. More interesting facts… Box Jellies • More toxic than Man-of-War • Stings can lead to heart failure within minutes • Tentacles may reach 15 feet

  18. CTENOPHORA: THE COMB JELLIES • Diploblastic??; Biradial Symmetry • Swim with 8 rows of ciliary combs • Have 2 long tentacles with sticky cells • Colloblasts • Eat large amounts of fish larva & plankton • Mouth + 2 anal pores • Introduced/Invasive species (Black Sea)

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