Radiata
Parazoa
no true tissues
Bilateria
Eumetazoa
Multicellularity
QUIZ (CHAMPACA)
1. True or False: Jellyfishes have no nervous
system.
2. What are the 2 stages of the life cycle of
jellyfishes?
3. What is the term used to describe the twotissue layer that Cnidarians possess?
4. Give one class under this Phylum
5. Give ecological significance of Cnidarians.
•Gr. “nettle”
•cnidocytes with
nematocysts
PHYLUM CNIDARIA
STINGING ANIMALS
•previously
“Coelenterata”
with the
Ctenophora
(coel + enteron)
•10 000 sp.
http://farm4.static.flickr.com/3085/2832954307_dc57ebb1a6.jpg, http://news.nationalgeographic.com/news/2006/01/images/060119_jellyfish.jpg,
http://www.seasky.org/wallpaper/assets/wallpaper_sea/anemones-1280.jpg,
http://www.aquariumdomain.com/images/corals/closedBrainCoral1.jpg
FORM AND
FUNCTION
DIMORPHIC BODY PLAN
http://www.reefed.edu.au/__data/assets/image/0005
/17987/polypdiagram.gif, http://3.bp.blogspot.com/GHG4p2wPVPs/TenLrQE0cyI/AAAAAAAAA_s/YZiq
_lfYItM/s1600/10a.JPG,
• radially-symmetric
• diploblastic
• 2-layered body wall (epidermis + gastrodermis)
• gelatinous mesoglea
• gastrovascular cavity (GVC)
• incomplete gut
• digestive sac with only one opening
FORM AND FUNCTION:
FEEDING
• predatory
• extracellular digestion in GVC  intracellular within cells
of gastrodermis
• circulation through diffusion
FORM AND FUNCTION:
RESPONSE
http://media-3.web.britannica.com/eb-media/35/73335-004-9E50A397.jpg
FORM AND FUNCTION:
MOVEMENT
Polyps: hydrostatic skeleton
Medusas: jet propulsion
Contractile fibers (not true
muscle tissues) + H2O in GVC
Fibers contract  medusa closes
 H2O forced out  forward
movement
FORM AND FUNCTION:
ASEXUAL THROUGH BUDDING
REPRODUCTION
SEXUAL THROUGH SYNCHRONIZED
RELEASE OF GAMETES
Phylum Cnidaria
Hydrozoa
Anthozoa
Scyphozoa
Cubozoa
conspicuous polyp
stage
polyp stage only
cup shaped medusa
stage
umbrella shaped
medusa stage
Hydra
Sea anemone
Aurelia
Coral animals
Mastigia
Chironex
Physalia
Praya
Cyanea
http://www.aaskolnick.com/hydr
a3.jpg,
http://www.walldesk.net/pdp/102
4/17/14/-Sea-Anemone.jpg,
http://www1.american.edu/ted/i
mages4/braw3.jpg,
http://www.oceanwideimages.co
m/images/2475/large/boxjellyfish-24M1211-16.jpg
ECOLOGY
Coral reefs
•budding produces new polyps, new
polyps lay down new limestone
•  growth rate,  lifespan
http://www.cdnn.info/eco/e04070
1a/e040701a.html
http://i2.cdn.turner.com/cnn/dam/assets/130201123703-01-guardian-0201-horizontal-gallery.jpg
IMPORTANCE
Coral reefs
•symbiotic relationships
with other plantlike
protists
•animal habitat
•protects land from wave
action
•tourism
•medical research
http://www.cdnn.info/eco/e040701a/e040701a.html
IMPORTANCE
Distribution of
corals
determined by:
•temperature
•water depth
•light intensity
Problems of corals:
•Human activity
•Coral bleaching
http://ih.constantcontact.com/fs113/1108454596610/img/168.jpg?a=1111854027677 ,
http://www.breef.org/oldsite/Portals/0/coralmcavbleached%20Sandy%20for%20web.jpg,
http://serc.carleton.edu/images/eslabs/corals/coral_bleaching_diagram.gif