Phylum Cnidaria contains stinging cells called cnidocytes that contain nematocysts. They have a sac-like body plan with a gastrovascular cavity. Their life cycle involves both asexual and sexual phases - polyps can reproduce asexually while medusae are the sexual phase. Important classes include Scyphozoa, Cubozoa, Hydrozoa, and Anthozoa. Cnidarians are ecologically important as they provide habitat and protect coastlines with coral reefs.

1. Phylum Cnidaria

2. DEFINING CHARACTERISTIC OF CNIDARIA
Contain
Stinging cells
Didermic
Sac Body Plan
Gastro-vascular Cavity

3. STINGING CELL

4. STINGING CELL
Specialized Cell is Cnidocyte that contain stinging
organelle
Nematocyst.
Nematocyst – has barbed and poisonous
thread. They produced toxin when discharged, they
help in the capture of prey or for defense

5. WHAT WILL HAPPEN WHEN JELLYFISH STING
YOUR SKIN?

6. How to Soothe a Jellyfish Sting
1. REMAIN CALM! THERE
ARE ONLY A FEW JELLY FISH
WHOSE STING IS DEADLY
OR POTENTIALLY DEADLY.
PANICKING WOULD BE
UNHELPFUL.

7. 2. Get out of the
water! Jellyfish
stings can be
extremely painful
and you could
lose your ability
to swim

8. 3. Remove stingers by
applying shaving foam
to the sting area.
Scrape the skin closely
with a razor, knife blade,
or credit card. If you don't
have a plastic card, rub
sand over it to dislodge
the stingers and rinse it
off in salt water

9. 4. Deactivate the
remaining stingers. In
the case of a plain old
jellyfish sting, blot or pour
3-10% percent acetic
acid solution (white
vinegar) on the sting with
a clean cloth.

10. 5. Remove any venom in the
skin by applying a paste of
baking soda and water and
using a cloth covering. If
possible, reapply paste every
15-20 minutes.

11. 6. Take a very hot shower. A
15-20 minute hot shower can
deactivate the venom of some
jellyfish

12. 7. Soothe any remaining
skin irritations with overthe-counter antihistamine
pills.

13. 8. Get medical care if the
victim is experiencing any
symptoms worse than
skin irritation or has
trouble breathing.

14. 10. Severe stings need to be
wrapped after treatment to
keep them from getting
infected

15. DIDERMIC
Consist of 2 tissue layer
Epidermic
 Gastrodermis


16. SAC BODY PLAN

The mouth serve as an
incurrent and excurrent
opening

17. GASTROVASCULAR CAVITY
Play an important role in
Digestion. Inner Cell depend
on water within the cavity for
gas exchange and
excretion.

18. ANATOMY OF CNIDARIA

19. Tentacles – contain sting cell
use in capturing prey
 Oral arm – Hold the prey then
pass out in the mouth
 Mouth – serve for food
entrance, metabolic waste exit
and passageway of gametes.


20. Nerve Net – nerve cells
interconnect to form a nerve
net below the epidermis
 Epidermis – outer covering
of Cnidaria
 Gonads – responsible for
production of gametes


21. REPRODUCTION

22. The life cycle of Cnidaria include two phases:
When there is an alteration of Generation
 Medusa – the sexual phase
 Polyp – asexual phase


23. 
Polyp – has mouth on the dorsal surface and tentacles
that point upward

Medusa – has a mouth on the ventral surface and
tentacles that point downward

24. LIFE CYCLE OF CNIDARIA

26. The adult male and female sea jellies releases gametes
2.
Fertilization occur in the water. Zygote will form that
eventually develop into a planula
3. The planula will eventually settle and attaches to a firm
surface. The planula then develops into a polyp with a
mouth and tentacles on its unattached end. The polyp
will develop a stack of medusa that will bud off.
4. The polyp will bud off immature sea jelly or ephyra then it
will develop into an adult sea jelly.
1.

27. CLASSES OF CNIDARIA
•Scyphozoa
•Anthozoa
•Hydrozoa
•Cubozoa

28. SCYPHOZOA
Cnidaria
with
dominant medusae
Aurelia
aurita
Cyanea capillata

29. CUBOZOA

The medusae is in cuboidal
shape with tentacles that hang
from each corner of bell
Chironex flexeri
 Chiropsalmus quadrumanus


30. STAUROZOA

Goblet-shaped, sessile,
attached by oral stalk to
sea weeds

Halyclystus auricula

31. HYDROZOA
Cnidaria with polyp dominant
 One of the few fresh water
cnidaria
 They are also found in
attached to underwater plant
or rocks, mostly in lakes and
ponds.

Hydra
 Obelia


32. ANTHOZOA

Stony coral, with no medusae
have a calcium carbonate
exoskeleton that contribute
greatly building of coral reef.
Fungia
 Corallium


33. IMPORTANCE OF CNIDARIA

34. THEY PROVIDE HABITAT FOR MANY MARINE
ORGANISM

35. THE REEF DECREASES THE FORCE OF THE INCOMING
WAVES, RESULTING IN PEACERFUL WATER AT THE SHORE

36. SEA CORALS ARE GOOD INDICATOR OF ENVIRONMENTAL
CHANGES. SEA CORALS ARE VERY SENSITIVE TO SUCH FACTOR
AS WATER POLLUTION

37. Multiple Choice. Choose the best answer in the following question
1. The jelly like layer in the cnidaria body wall
a.Nematocyst
c. Mesoglea
b. Mesohyl
d.Gastrocoel
2.The asexual phase of cnidaria
a.Polyp
c. Both polyp and medusa
c. Medusa
d. None
3.What do you call the free living larva of Cnidaria?
a.Planula b. Clydippids c.Nymphs
d. Lanula
4.Which of the following is NOT a Cnidarian
Characterisitic?
a.Contain stinging cell c. Didermic
b.Triploblastic
d.Sac Body Plan
5.Halyclystus belong to what class?
a.Staurozoa
c. Hydrozoa
b.Cubozoa
d. Anthozoa