Name ______Date ______Period ______

Phylum Cnidaria Notes Organizer

List members of the Phylum Cnidaria:sea anemones, sea pen, sea fan, sea plume, hydra, jellyfish,

Portuguese Man O’ War, Box jellyfish

  1. Cnidaria Body Structure
  2. Define polymorphism: more than one body form
    2 different body forms: polys or medusa
  3. Describe the characteristics of the polyp body form:
    tube or column with tentacles around mouth; most are sessile

-Identify examples of cnidarians whose adult stage is the polyp form:
hydra, sea anemone

  1. Describe the characteristics of the medusa body form:umbrella shape with

Tentacles around mouth (tentacles face downward); motile, free-swimming

-Identify examples of cnidarians whose adult stage is the medusa form:

  1. Structure and function of tentacles:have nematocytes (stinging cells); coiled thread discharges like a harpoon; contains neurotoxin that paralyzes prey
  1. Illustrate the generalized cnidarian life cycle:
  1. Level of Organization
  2. What is the highest level of cnidarian cellular organization?
    A. has tissue B. no organs
  3. Symmetry
  4. Cnidarians exhibit radial symmetry.
  5. Habitat
  6. Cnidarians are mostlyfound in marine aquatic environments, although some are found in

fresh water.

  1. Feeding
  2. Cnidarians are heterotrophic.
    carnivores - predators
  3. Use the arrows to list the cnidarian feeding process.
  1. Cnidarians have an INCOMPLETE digestive tract. Digestive tract makes a loop.
  1. Respiration
  2. Respiration in cnidarians is able to occur through what process?

by way of diffusion

  1. A cnidarian body is 2 cell layers thick.Have ectodermis and endoderm that forms gastrodermis.
  1. Internal Transport
  2. Internal transport in cnidarians is able to occur through what process?
    by way of diffusion
  3. Excretion
  4. Excretion in cnidarians is able to occur through what process?
    by way of diffusion
  5. Response
  6. Describe the cnidarian response system: NO cephalization or nervous system

(Cephalization means definite “head cells”with sensory cells)

  1. Cnidarian sensory cells: nerve net around mouth

detect chemicals (chemoreceptors)

Thigmoreceptors (detect touch )

Photoreceptors (detect light)

-Eyespots: ocelli

Statocysts (used for balance )

  1. Locomotion
  2. Medusa vs. Polyp Locomotion:
    Polyps – sessile medusa – free swimming
  3. What are some exceptions to the rule? hydra – tumble on tentacles

Sea anemones glide on pedal disc

  1. Reproduction
  2. Describe asexual reproduction in cnidarians:
    budding from polyps or medusae
  1. Describe sexual reproduction in cnidarians:
    a. medusa release sperm and egg

b.some are monoecious but MOST are dioecious (2 houses)

c. larvae free-swimming

  1. Ecological Role of Cnidarians
    a. Describe the ecological role of cnidarians: a. predators with prey

b. neurotoxins in medical research

c. coral - jewelry, building reefs

d. coral reefs – habitat for many – great diversity – protect coastline

e. symbiosis with other animals

Cnidarian Structure: 2 body forms - Polyp (above) – stalk Medusa (below) – bell-shaped!

Cnidarian Classes:

Class Name / Anthozoa
Flower animals / Hydrozoa
Water animals / Scyphozoa
Cup animals / Cubozoa
Cubed shaped
Characteristics / Polyp stalk with tentacles facing upward around mouth / Hydra - found in fresh water ONLY!
Port Man O’ War Colony of polyps / Medusa with tentacles hanging down
Mouth at bottom with tentacles going up
TRUE jellyfish! / Medusa
Very small
Clear, nearly transparent,
1-3” tall
Tentacles 2-5 feet long
Examples / Corals: sea fan
Sea plume
Sea pen
Sea anemone / Portuguese Man O’
War – marine
Obelia
Hydra – polyp form with a stalk / Sea Nettle
Lion’s Mane / Box jelly- Sea Wasp