Lesson 10.2: Cnidarians (Jellies & Corals) *Refer to Chapter 6 in your Textbook

Learning Goals: I can label the anatomy of a cnidarian. I can describe the life cycle of a cnidarian. I can differentiate between the different classes of cnidarians.

Cnidarian Characteristics: Tissues, but still no organs Radial Symmetry: have a central axis (like a pizza) Two Body Plans: Polyp: sessile stage Medusa: free-floating stage

Cnidarian Structures: Tissues: Ectoderm (or Epidermis): outer most layer of cells Mesoglea: gelatinous material making up majority of the animal’s body Endoderm: lining of the inside of the body Gastrovascular cavity: (pre-stomach) where digestion occurs Mouth/Anus: food enters and waste is removed

Cnidarian Structures: Tentacles: feeding and locomotion Nematocysts: Coiled stinging dart ready to strike located on tentacles Cnidocytes: Stinging cells located within the dart

Cnidarian Life Cycle: Both asexual and sexual in same cycle Asexual: From polyp to medusa Sexual: From medusa to polyp *Draw the diagram on the board

Cnidarian Classes: Class Hydrozoa: Colony = individual members physically connected and adapted to share resources Ex. Portuguese Man of War Individual polyps have different roles: Feeding - Carnivorous Predator Reproduction Defense

Cnidarian Classes: Class Schyphyzoa “True Jellies” Medusa is the predominant stage Carnivorous Predator Class Cubozoa “Box Jellies” Most venomous jellyfish in the world

Cnidarian Classes: Class Anthozoa “Flower animal” Sea anemones and corals No medusa stage, Sessile Corals secrete a hard skeleton Suspension feeding: grab plankton from the water while sessile

Cnidarian Ecological Roles: Symbiotic Relationships: Zooxanthellae with Coral Clownfish with Anemone Habitat: Coral reefs are the most diverse ecosystem on Earth Human: Tourism Pets Medicine