Animal science presentation

1. CNIDARIA
GROUP 2

2. What is cnidaria?
Cnidaria is a phylum under the kingdom Animalia, and it
includes over 11,000 species of aquatic animals found in
both freshwater and marine environments. Some examples
of cnidarians are jellyfish, hydroids, sea anemones, corals,
and some of the smallest marine parasites.

3. CNIDARIA:

4. CHARACTERISTICS OF CNIDARIA:
• 1. Radial Symmetry:
Cnidarians typically exhibit
radial symmetry, which
means their body parts are
arranged around a central
axis. This allows them to
be equally symmetrical
from any direction.

5. 2. Cnidocytes:
• Cnidarians possess
specialized cells called
cnidocytes, which contain
stinging structures called
nematocysts. These cells
help in capturing prey and
defense. When triggered,
the nematocysts shoot out
a barbed thread that injects
toxins into the prey or
predator.

6. • 3. Tissue Organization:
Cnidarians have a simple
tissue organization. They
have two layers of cells: an
outer layer called the
epidermis and an inner
layer called the
gastrodermis

7. 4.Polyp and Medusa Forms:
• Cnidarians exhibit two main
body forms: the polyp and
the medusa. The polyp form
is cylindrical and attached to
a substrate, while the
medusa form is bell-shaped
and free-swimming.

8. 5.Tentacles:
• Cnidarians have tentacles
surrounding their mouth or
oral opening. These
tentacles are armed with
cnidocytes and are used for
capturing prey and bringing
it to the mouth.

9. • 6. Gastrovascular Cavity:
Cnidarians have a central
cavity called the
gastrovascular cavity, which
serves both as a digestive
and a circulatory system.
Nutrients are absorbed
directly into the cells lining
the cavity.

10. 7. Nerve Net:
• Cnidarians have a
decentralized nerve net
that allows them to
respond to stimuli. While
they lack a centralized
brain, they can still exhibit
simple behaviors and
responses.

11. 8. Reproduction:
• Cnidarians can reproduce
both sexually and asexually.
They can reproduce
asexually through budding,
where new individuals grow
as outgrowths from the
parent organism. They can
also reproduce sexually by
releasing eggs and sperm
into the water, where
fertilization takes place.

12. CLASSIFICATION OF CNIDARIA:
Class Anthozoa
• This class include
organisms such as corals,
and sea pens. They are
exclusively polyps and do
not have a medusa stage
in their life cycle.
Corals Sea pens

13. CHARACTERISTICS OF CLASSIFICATION
Anthozoa
• Exclusively polypoid, with
no medusoid stage.
• Includes sea anemones
and corals that form reefs.
Anemones
Corals

14. Class Hydrozoa
Hydrozoans are a diverse
class of cnidarians that
include organisms such as
hydroids, fire corals, and
Portuguese man o' war.

15. CHARACTERISTICS OF CLASSIFICATION
Hydrozoa
• Includes both
polypoid and
medusoid forms.
• Examples include the
Portuguese man o'
war and fire corals.
Portuguese
Fire corals

16. Class Scyphozoa:
Scyphozoans are commonly
known as true jellyfish. They
have a dominant medusa
stage in their life cycle and
typically have a bell-shaped
body with tentacles hanging
down from the edge.

17. CHARACTERISTICS OF CLASSIFICATION
Scyphozoa:
• Exclusively medusoid, with
no polypoid stage.
• Commonly known as
jellyfish.
Jellyfish

18. Class Cubozoa
Cubozoans, also known as
box jellyfish, are a small
class of cnidarians. They
have a cube-shaped bell
and tentacles that hang from
each corner. Some species
of cubozoans are known for
their potent venom, which
can be harmful to humans.

19. CHARACTERISTICS OF CLASSIFICATION
Cubozoa
• Box-shaped medusoid
body form.
• Includes box jellyfish,
known for their potent
venom.

20. Class Staurozoa
Staurozoans, also called
stalked jellyfish, are a small
class of cnidarians. They are
unique in that they have a
polyp-like body form
throughout their life cycle and
are attached to a substrate by
a stalk. They have tentacles
surrounding their mouth.

21. CHARACTERISTICS OF CLASSIFICATION
Staurozoa
• Stalked jellyfish with a
stalk-like structure.
• Unique body plan and
feeding behavior.