3_Cnidarians Flashcards
Cnidos means
stinging thread
CNIDARIA (“Coelenterata”=“_______t”)
hollow gut
What are the GENERAL MORPHOLOGICAL FEATURES of Cnidarians?
- Body plan: polyp and/or medusa
- Radially Symmetrical
- Diploblastic (two layers of living tissues)
- With intracellular organelles called “cnidae” (nettle or stinging thread) “nematocysts”
What is the gelatinous layer (non living but may contain living cells), with amoebocytes for digestion, nutrient transport and storage, wound repair, antibacterial defense
Mesoglea
a cnidoctye is properly
called a _________ during
its development;
produces the cnidae
* ___________ is one type of
cnidae
cnidoblast, nematocyst
3 major types of nemaytocyts
- Volvent (desmoneme: spirocysts: small pear- shaped nematocysts)
- Penetrant (stenotele:large nematocysts)
- Glutinant (ptychocysts)
Functions of nemaytocyts?
food collection, defenses and
locomotion:
* wrapping around small objects
* sticking the surface
* penetrating surfaces
* secreting proteinaceous toxin
Locomotion and movement of cnidarians
- swim by a form of jet propulsion
- swim by waggling their base
- pedal disc gliding
What is the receptors for light, balance, touch, and chemical detection?
Rhopalia
What is the feeding habit?
- predation
- absorption of dissolved organic matter
- filter feeding
- with endosymbionts (organism that lives within the body or cells of another organism)
Why clownfish can live on the sea anemone?
Their skin have thick mucus layer that gives them protection.
What are their reproduction?
Sexual reproduction
* Fertilization
Asexual reproduction
* Budding
* Fission
* Fragmentation/regeneration
* Polyp bailout/Polyp expulsion
Sexual reproduction:
Spawning of anthozoans (corals)
What do you call the stinging cells? and what do you call the structures within it?
Cnidocytes
Nematocysts
a polyp splits into
plate-like segments stacked atop one
another in a tower called a strobila.
After a segment separates from the
strobila, it is called an _______, a juvenile jellyfish
Strobilation
ephyra
CLASSES UNDER PHYLUM CNIDARIA
- Class Anthozoa
- Class Hydrozoa
- Class Cubozoa
- Class Scyphozoa
o Mostly marine
o Mostly colonial in form
o Usually includes asexual
and sexual reproduction
o Polyp and medusa
o Ex. Obelia sp.
- Class Hydrozoa (hydroids)
Class Hydrozoa:
protective tube for colony made up of polysaccharide, protein and chitin
Perisarc
Class Hydrozoa:
modules specialized in feeding
Gastrozooids
Class Hydrozoa:
Reproduction. A single hydrozoan can
produce a gonochoristic or
hermaphroditic medusa
Gonozooids
Portugese man-of-war scientific name and order?
Physalia physalis
Siphonophora
“fire coral”
o used to be “Order Hydrocorallina”
o form massive colonies that resemble
true corals
o secrete calcareous skeleton
o restricted to warm waters
o dactylozooids abundant and potent
Hydrocorals
A colony of individual organisms (polyp or zooids)
o Free floating hydrozoan colonies in which
medusoid and polyploid morphs are present simultaneously
o Carnivore
o Float size: ~12-30 cm long, 5-13cm wide
o Tentacles: ~10m long but can be shorter or longer
Siphonophora/Siphonophores
Largest class within phylum cnidaria, polyp form
- Class Anthozoa (corals)
