Friday, October 23, 2020

Animal Kingdom - Notes | Class 11 | Part 10: Echinodermata

4. ANIMAL KINGDOM

PHYLUM ECHINODERMATA (SPINY SKINNED ANIMALS): GENERAL CHARACTERS

  • Grades of organization:
    • Organ system.
  • Symmetry:
    • Adults radial. Larvae bilateral.
  • Germ layers:
    • Triploblastic.
  • Coelom:
    • Coelomate.
  • Habit and habitat:
    • Exclusively marine.
  • Digestive system:
    • Complete.
    • Ventral mouth and dorsal anus.
  • Respiratory system:
    • Skin gills. Water Vascular system.
  • Circulatory system:
    • Open type.
  • Reproduction:
    • Dioecious.
    • External fertilization.
    • Development is indirect.
    • Ciliated free-swimming larva.
  • Unique features:
    • They have an endoskeleton of calcareous ossicles (Spiny bodied).
    • Head absent.
    • Water vascular system for locomotion, respiration, capture & transport of food.
    • Excretory system absent.
  • Examples:
    • Asterias (Starfish)
    • Echinus (Sea Urchin)
    • Echinocardium
    • Antedon (Sea Lily)
    • Cucumaria (Sea Cucumber)
    • Ophiura (Brittle Star)
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