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Phylum Cnidaria

Phylum Cnidaria. Characteristics: Diploblastic ; tissues and nervous system Specialized cells= Cnidocytes (“stinging cells”) 4 main classes (over 9,000 species): Class Hydrozoa Class Scyphozoa = true jellyfish Class Cubozoa Class Anthozoa = sea anemones and corals.

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Phylum Cnidaria

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  1. Phylum Cnidaria Characteristics: Diploblastic; tissues and nervous system Specialized cells= Cnidocytes (“stinging cells”) 4 main classes (over 9,000 species): Class Hydrozoa Class Scyphozoa= true jellyfish Class Cubozoa Class Anthozoa= sea anemones and corals

  2. Body organization (=Diploblastic) • Outer layer (Ectoderm)= Epidermis • Inner layer (Endoderm)= Gastrodermis • Mesoglea= Jelly-like layer in-between • Hydrostatic skeleton = gastrovascular cavity which fills with water • Body Forms • 2 body forms which alternate through life history: *polyp= sessile column attached by aboral end *medusa= free swimming; inverted bowl shape

  3. http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/cnidariaDiagram.jpeghttp://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/cnidariaDiagram.jpeg

  4. Cnidocytes- Cells which produce cnidae used for attachment, defense, and feeding. *There are about 30 kinds of cnidae. Nematocyst – One type of cnidae that may discharge a long tube armed with spines that penetrate prey. These spines deliver paralyzing toxins. • http://www.barbaraharmon.com/illus_art/anatomy_biology/nematocyst.jpg http://creationwiki.org/pool/images/5/5f/Nematocyst_discharged.PNG

  5. Reproduction • Most cnidarians are dioecious (separate sexes) • Sperm and eggs released into water/ gastrovascular cavity • Fertilized embryo turns into free swimming larvae called planula; planula attaches to substrate; polyp develops; medusa forms later by budding from polyp http://universe-review.ca/I10-82-cnidaria.jpg

  6. Class Hydrozoa • The onlycnidaria class with: • Freshwater species (as well as marine) • Nematocysts and sex cells only in epidermis • Velum (shelf-like lip around ring canal) present on most medusa • Mouth at end of tubelikemanubrium • Some species do not have medusa stage; some species only have very small polyp stage

  7. Example: Hydra (freshwater; no medusa) http://www.scientificillustrator.com/art/microscopic/hydra.jpg http://www.donsmaps.com/images2/herculeshydra.jpg http://www.isi.edu/robots/self_heal_html/hydra.JPG

  8. Other Examples… manubrium http://www.microscopy-uk.org.uk/mag/imgmay01/obelob.jpg Obelia http://tinypic.com/view.php?pic=9u6z6a&s=4 Portuguese Man-of-War

  9. Class Scyphozoa • “True jellyfish” (Medusa is dominant stage) • Lack a velum • Cnidocytes in epidermis & gastrodermis • Sex cells in gastrodermis • Gastrodermal cells have cilia • Feed from oral lobes, hanging from manubrium • Some species have an ocellus/ocelli (pl.) (photoreceptor/eye) • All marine

  10. Largest Jellyfish: lion's mane jellyfish http://www.pwlf.org/IMG_0129.JPG http://i.telegraph.co.uk/telegraph/multimedia/archive/01423/LionsManeJellyfish_1423038c.jpg http://farm4.static.flickr.com/3192/3081451429_b4b832e974.jpg

  11. http://www.biopix.com/Temp/JCS%20Aurelia%20aurita%2041520.jpghttp://www.biopix.com/Temp/JCS%20Aurelia%20aurita%2041520.jpg http://latimesblogs.latimes.com/photos/uncategorized/2008/09/11/do_they_have_their_own_moonwalking_.jpg Most Common Jellyfish: Moon Jellyfish

  12. Class Cubozoa • Medusa “cuboidal” (cube) shaped (Tentacles hang from corners) • Some species have no polyp stage/or unknown • Active swimmers and feeders • Some of the most deadly jellyfish (most deaths within 5 minutes) • All marine

  13. http://www.brisbanetimes.com.au/ffximage/2007/03/30/470_box,0.jpghttp://www.brisbanetimes.com.au/ffximage/2007/03/30/470_box,0.jpg Most Toxic Jellyfish: Box Jellyfish of Australia- AKA “Sea Wasp” http://lifeinthefastlane.com/wp-content/uploads/2008/12/box-jellyfish-fatal-sting.jpg

  14. Class Anthozoa:Anemones and Corals • Lack Medusa stage (all polyps) • All marine • Anthozoan polyps are more complex than hydrozoan polyps!

  15. Anemones • Solitary • Attach to bottom by pedal disk • Mesenterial filaments and acontia bear cnidocytes • Muscle fibers gastrodermal (they can “deflate” and collapse if threatened) • Movement by sliding on pedal disk, crawling on side, walking on tentacles (some can swim!) • Food: Invertebrates, fishes • Both sexual and asexual • Both monoecious and dioecious

  16. http://www.lauramhaight.com/images/portfolio/PJAP_PinkSeaAnemone.jpghttp://www.lauramhaight.com/images/portfolio/PJAP_PinkSeaAnemone.jpg http://images.paraorkut.com/img/wallpapers/1024x768/c/clown_fish_and_a_sea_anemone-2640.jpg http://oceanexplorer.noaa.gov/explorations/deepeast01/logs/sep26/media/anemone_590.jpg http://www.seaotter.com/marine/research/stomphia/coccinea/pics/swimanemone.jpg

  17. Corals • Stony Corals • Colonies form coral reefs • Calcium carbonate exoskeleton • Similar to anemones • Known for symbiosis with algae called zooxanthellae (these algae use photosynthesis to give products to coral; corals metabolism also provides back to algae) • Colors come from zooxanthellae! • 90m depth limit (NEED light for zooxanthellae) • No zooanthellae = coral bleaching

  18. http://www.marineaquarium.nl/images/Acropora%20prostrata.gif http://www.advancedaquarist.com/2007/12/aafeature2_album/figure1.jpg

  19. http://www.stormcenter.com/media/envirocast/archive/060912/060912_07.jpghttp://www.stormcenter.com/media/envirocast/archive/060912/060912_07.jpg Coral Bleaching http://www.globalwarmingart.com/images/4/48/Partially_Bleached_Coral.jpg http://www.gbrmpa.gov.au/__data/assets/image/0006/13749/Bleaching-and-mortality-dia.gif

  20. Soft Coral • Internal skeleton of protein or calcium carbonate • Some have feather-like tentacles • Group Includes: sea fans, sea pens, sea whips, etc. http://californiadiveboats.com/Peace/2005.05.06-07/P5072490F2xlr.jpg http://www.noaanews.noaa.gov/stories2007/images/seafan.jpg Sea Pen Sea Fan

  21. Phylum Ctenophora • 90 species: Sea Walnuts or Comb Jellies • Spherical form (or flattened) • Most diploblastic- Some triploblastic! • True muscle cells in mesoglea • Anal opening • Comb rows (bands of cilia) from oral to anal openings • Tentacles have colloblasts (adhesive cells) that capture prey • Monoecious/sexual reproduction external • Known for bioluminescense

  22. http://images.enature.com/seashore/seashore_l/sc0127_1l.jpg http://pt-lobos.com/ctenoimg/leucothea_pulchra-com_bdb13.jpg http://upload.wikimedia.org/wikipedia/commons/1/1e/Sea_walnut,_Boston_Aquarium.jpg

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