Download 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
• 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
http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/cnidariaDiagram.jpeg
• 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_a
rt/anatomy_biology/nematocyst.jpg
http://creationwiki.org/pool/images/5/5f/Nematocyst_discharged.PNG
• Reproduction
http://universe-review.ca/I10-82-cnidaria.jpg
– 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
Class Hydrozoa
• The only cnidaria 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 tubelike manubrium
• Some species do not have medusa stage;
some species only have very small polyp stage
• 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
• Other Examples…
http://tinypic.com/view.php?pic=9u6z6a&s=4
manubrium
http://www.microscopy-uk.org.uk/mag/imgmay01/obelob.jpg
Obelia
Portuguese Man-of-War
Class Scyphozoa
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“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
http://www.pwlf.org/IMG_0129.JPG
Largest Jellyfish:
lion's mane jellyfish
http://i.telegraph.co.uk/telegraph/multimedia/archive/01423/LionsManeJellyfish_1423038c.jpg
http://farm4.static.flickr.com/3192/3081451429_b4b832e974.jpg
http://www.biopix.com/Temp/JCS%20Aurelia%20aurita%2041520.jpg
http://latimesblogs.latimes.com/p
hotos/uncategorized/2008/09/11/
do_they_have_their_own_moonw
alking_.jpg
Most Common Jellyfish:
Moon Jellyfish
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
http://www.brisbanetimes.com.au/ffxi
mage/2007/03/30/470_box,0.jpg
Most Toxic Jellyfish:
Box Jellyfish of AustraliaAKA “Sea Wasp”
http://lifeinthefastlane.com/wpcontent/uploads/2008/12/boxjellyfish-fatal-sting.jpg
Class Anthozoa: Anemones and Corals
• Lack Medusa stage (all polyps)
• All marine
• Anthozoan polyps are more complex than
hydrozoan polyps!
• 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
http://www.lauramhaight.com/images/portfolio/PJAP_PinkSeaAnemone.jpg
http://images.paraorkut.com/img/wallpapers/1024x7
68/c/clown_fish_and_a_sea_anemone-2640.jpg
http://oceanexplorer.noaa.gov/explorations/de
epeast01/logs/sep26/media/anemone_590.jpg
http://www.seaotter.com/marine/research/sto
mphia/coccinea/pics/swimanemone.jpg
• Corals
– Stony Corals
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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
http://www.marineaquarium.nl/image
s/Acropora%20prostrata.gif
http://www.advancedaquarist.com/2007/12/aafeature2_album/figure1.jpg
http://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
– Soft Coral
• Internal skeleton of protein or calcium carbonate
• Some have feather-like tentacles
• Group Includes: sea fans, sea pens, sea whips, etc.
http://www.noaanews.noaa.gov/stories2007/images/seafan.jpg
http://californiadiveboats.com/Peace/2005.05.06-07/P5072490F2xlr.jpg
Sea Pen
Sea Fan
Phylum Ctenophora
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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
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/commo
ns/1/1e/Sea_walnut,_Boston_Aquarium.jpg