Download Cnidarians

Cnidarians (Greek “cnidos” means __________________)
Common names: corals, jellyfish, sea anemones
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1st simple animals to have __________________, more complex than sponges
Tissues enable them to swim, engulf prey, and respond to stimuli
________________________ symmetry
Body can be divided in half anywhere along a central axis
No head, front or back
Anatomy
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Two basic body forms
Polyp (faces upward)
Medusa (upside-down polyp)
Central mouth opens into _______________________ (gut cavity)
Mouth surrounded by _______________________
_____________ attaches to substrate with a _______________________
Tentacles have specialized _____________________, called ________________, used for capturing
prey and _____________________
Types of Cnidarians:
o Remember classification:
o Kingdom Animalia
o Phylum Cnidaria
 Class …
o Class _______________________(Portuguese Man o’ War)
o Colonial organisms
o Wide range of body forms
o Consist of feathery or bushy colonies of tiny polyps
o Polyps can be specialized for feeding, defense or reproduction
o Toxins from nematocysts can produce painful reactions in humans
o Class ______________________ (True jellyfish)
o Rounded body (bell) can be up to 2 meters
o Swim with rhythmic contractions of the bell
 Among the most dangerous marine animals, giving extremely painful - sometimes deadly
stings
o Class ______________________ (corals and anemones)
o Solitary or colonial polyps that lack a medusa stage
o Largest # of species in this class of Cnidarians
o Corals - CaCO3 (Calcium Carbonate) skeleton forms coral reefs
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Some have fleshy colonies with large polyps and no skeleton
What makes a cnidarian a cnidarian?
o ____________________ (____________________in tentacles)
o _________________ contain fluid filled capsule that is ejected
Where do they live?
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Polyps are ____________________________.
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Medusas are __________________________.
What/how do they eat?
o Mostly _________________________
o Use _______________________ to catch prey
o Some contain __________________ (that are even strong enough to kill humans) that are used to
_________________________
Behavior
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Cnidarians don’t have ___________________________.
Transmit impulses in all directions
Some can recognize other members of the same species.
Some attack and kill anemones of other species using ________________.
Some_______________ have primitive eyes (light sensitive)
capable of ___________- movement toward (______________) or away from
(_______________) light
Reproduction
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Cnidarians reproduce both __________________ and __________________.
________________________ (produces new organism genetically identical to parent)
___________________ to form a new organism
May stay ________________ to the parent organism or break off to form a new one.
Cnidarians (like sponges) also have the ability to ______________________, so that broken parts form
new organisms.
_________________ Reproduction
Most cnidarians are _________________ (have separate sexes).
The ____________(sperm and eggs) are broadcast into the water and fertilization is external.
Free-swimming _ ___________ forms, which permits dispersal for sessile forms. (Larvae)