Phylum Cnidaria
= jellyfish, anemones, corals, cube jellies and hydrozoans
Cnidarian Characteristics
Radial symmetry
Diploblastic
Majority marine
Polymorphism
Nematocysts
Planula
Cnidarian Body Plan
Epidermis, gastrodermis
& mesoglea
Polyp
Cylindrical
Pedal disk or physa
Terminal mouth
Dactylo-, gono-, gastro-,
siphonozooids
Medusa
Exumbrella, subumbrella
Marginal tentacles
Manubrium
Reproductive stage
Nutrition and Digestive System
Carnivorous
Trap prey or suspension
feeders
Symbiotic algae
(particularly corals)
Digestion= extra- and
intracellular
One digestive opening
only
http://www.youtube.com/watch?v=HheMqLyw1d8&feature=related
Muscular System
NOT mesodermal
Contractile extensions
= myonemes
Longitudinal muscle
fibers
Nervous System
No CNS
Network of neurons = arranged in 1-2 nerve nets
Neuromuscular and sensory network
Sensory Structures
1.
2.
3.
4.
5.
Mechanoreceptors = hairlike, in area of cnidocytes
Rhopalia = variety of structures
Statocysts
Ocelli = pigment cup
Eyes = in cubozoans, located near bell margin
Unique Defense System
Nematocysts in cnidocytes
Used in defense and prey capture
Reproduction and Lifecycles
Sexual
Dioecious
Hermaphroditic
Planula
Scyphozoa
Asexual
a. Budding
b. Strobilation
c. Frustule
d. fission
http://vimeo.com/13496458
Symbiosis and Interactions
1.
2.
3.
4.
Anemones and hermit crabs
Nudibranchs
Clownfish and anemone
Zooxanthellae
Classification
Anthozoa
Stauroszoa
Cubozoa
Scyphozoa
Hydrozoa