Cnidarian Body Forms
•Both body plans show radial symmetry
(arrangement of body parts around a central axis)
Objectives: 1) Illustrate
cnidarian reproduction. 2)
Draw and label a medusa and
polyp. 3) Describe how
cnidarians sting and capture
prey.
Cnidocytes: stinging cells that release a
______________________________________.
Extracellular Digestion
Food enters the gastrovascular cavity where
enzymes break it down and cells lining the cavity
____________________________________.
2) Marine:
1.More complex than freshwater hydrozoans.
2.Can form colonies.
3.Example:
___________________________________.
Hydrozoans
1) Freshwater:
Example: ___________
Movement: somersault motion .
Attach to rocks and plants through a basal disk.
Cnidarian Reproduction
Asexual Reproduction: Budding
Sexual Reproduction: Male and Female Medusa
nongender Polyp _______________________
What does this life cycle remind you of?
What does a planula resemble?
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Classes of Cnidarians
#1 True Jellyfish:
Most jellyfish seen are at the medusa stage
of their life cycle.
Active predators
#2 Anthozoans
Anthozoans exist only as a polyp (no medussa)
Examples: ________________________
3) Jellyfish Relatives
a.These creatures do not belong to phylum
cnidaria
b.Exist only as a medusa.
c.Example1: Comb Jelly (sticky tentacles, no
stingers)
d.Example 2: Box Jellies:
i.cube-shaped medusa
ii. tentacles found at each corner of the
“box”
iii.______________________
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