1. ANIMAL KINGDOM
PHYLUM CNIDARIA
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ABBOTTSCOLLEGE

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4. Includes between 9 000 and 11 000 species
PHYLUM CNIDARIA
Includes between and species
Includes the plant like hydroids, the flower like sea anemones, the jelly-fish, bluebottles and the hard corals

5. BODY PLAN OF CNIDARIA Acoelomate (have no body cavity) Radial symmetry
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Acoelomate (have no body cavity)
Radial symmetry
Diploblastic tissue layers
Digestive cavity with a single opening
The body wall is made up of three layers
But there are only two layers of cells
(the ectoderm and endoderm)
The middle layer (mesogloea) is jelly

6. DIPLOBLASTIC TISSUE LAYERS
The ectoderm forms
the epidermis
The endoderm forms
the gastrodermis (around
the gut)
There is a layer of jelly
between the two = mesogloea
BODY WALL CNIDARIA

8. RADIAL SYMMETRY Suits their sessile or free floating mode of living
Makes them aware of what is happening all around them

9. DIGESTIVE CAVITY WITH A SINGLE OPENING
Serves as both a mouth and an anus
Inefficient digestive system
Have a ring of tentacles around the opening to catch food
Have specialised stinging cells or cnidocytes
Which contain stinging organelles called nematocysts to capture their prey and defend themselves against predators

10. Hydra is a genus of small, simple, fresh-water animals that possess radial symmetry. 
Hydra are predatory animals belonging to the phylum Cnidaria 

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16. REPRODUCTION
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Have a dimorphic life cycle (develop two basic body forms)
Medusa
Free swimming and umbrella shaped
Develops gonads
Reproduces sexually to produce a free-swimming planula larva
Polyp
Develops from the larva
May occur singly (eg anemones)
Or in enormous marine colonies (eg corals)

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18. Life cycle Cnidaria

20. Coral
Coral Reef
Corals are marine invertebrates in phylum Cnidaria typically living in compact colonies of many identical individual "polyps".

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25. TO DO PASTE IN DIAGRAMS IN YOUR WORKBOOK TEXTBOOK PAGE 78
LEARNING ACTIVITY 1
QUESTIONS 1, 2 AND 3
BODY PLANS OF ANIMALS
PASTE IN DIAGRAMS
IN YOUR WORKBOOK

26. THE END