PHYLUM COELENTERATA CNIDARIANS

1
PHYLUM COELENTERATA(CNIDARIANS)

• Pages 323- 325

2
3 CLASSES OF COELENTERATES

• Hydrozoa Hydra
• Scyphozoa Jellyfish
• Man of War
• Anthozoa Corals
• Sea Anemone
• Page 323 Figure 9

3
PHYSICAL CHARACTERISTICS

• 1. Where do they live?
• All live in water most in salt water but
  the hydra lives in fresh water
• 2. Symmetry radial (see page 316)
• Body Structure is more complex than a sponge
  (therefore they can eat larger animals)

4

• 4. Cellular Structure
• like a sac with one opening mouth-like
  structure where food enters and leaves (not like
  the sponge)
• 2 cell layers ectoderm protects and covers
  outside
• endoderm inner
  layer that lines the
• 
  sac-like digestive cavity
• they have specialized
  cells
• organized tissues muscle tissue and a nerve
  net
• Why?
  Refer to page 323
• Central cavity with only 1 opening called the
  gastrovascular cavity
• - this is the opening (mouth) where food
  enters and
• leaves
• All have tentacles with nematocysts
• tentacles arm like projections
  surrounding the mouth
• nematocyst stinging cells on the
  tentacles which
• shoot poisonous
  threads or darts

5
Body Forms

• Polyp diagram page 324
• See overhead diagram
• Medusa diagram page 324
• See overhead diagram

6
LOCOMOTION

• Stays in place attached to rock
• examples sea anemone and coral
• Medusa
• example jellyfish
• move around swim by pumping water in and
  out of digestive cavity
• called jet propulsion pumping water in and
  out of cavity
• Polyp
• example hydra
• crawls
• See diagram

7
FOOD GETTING

• captures food with nematocysts by paralyzing
  small animals that swim into tentacles
• Nematocyst fire poison darts
• Paralyzes prey
• Tentacles bring food to mouth

8
REPRODUCTION

• Sexually sperm and egg
• separate sexes
• Asexually
• Budding example Hydra
• Regeneration