Echinodermata

• What class do sea lilies and feather stars belong to?

  Class Crinoidea
• What subphylum includes brittle stars?

  Subphylum Asterozoa
• What is the defining characteristic of Class Crinoidea?

  Body supported by stalk or cirri
• How many living species of echinoderms are there?

  6,500 living species
• What is the primary function of the water vascular system?

  Locomotion, food and waste transport
• What type of symmetry do adult echinoderms exhibit?

  5 pointed radial symmetry
• What is the composition of the echinoderm endoskeleton?

  Calcareous ossicles formed from mesoderm
• What is the function of tube feet in echinoderms?

  Locomotion and food collection
• What is the role of madreporite in the water vascular system?

  It acts as a sieve plate
• How do tube feet contribute to echinoderm locomotion?

  By coordinated contraction and retraction
• What is the function of the hemal system in echinoderms?

  Transport nutrients from coelomic fluid
• What is autotomy in echinoderms?

  Deliberate shedding of arms
• What type of feeding do most echinoderms exhibit?

  Suspension or deposit feeding
• What is the primary respiratory method in echinoderms?

  Primarily diffusion
• What is the significance of catch tissue in echinoderms?

  Alters stiffness for feeding and locomotion
• What is the larval stage of Class Holothuroidea?


  None
• How do Class Echinoidea's ossicles differ from other classes?

  They form a rigid test
• What is the common name for Class Holothuroidea?

  Sea cucumbers
• What is the primary diet of Class Holothuroidea?

  Mostly deposit feeders
• How does the locomotion of brittle stars differ from sea stars?

  Brittle stars use snake-like movement
• What are the major components of the water vascular system (WVS)?

  • Madreporite
  • Stone canal
  • Ring canal
  • Radial canal
  • Ampullae
  • Podia
• What are the defining characteristics of the five classes of echinoderms?

  • Class Crinoidea: Body supported by stalk or cirri
  • Class Stelleroidea: Arms extend from a central disc
  • Class Echinoidea: Rigid test formed by ossicles
  • Class Holothuroidea: Worm-shaped body with reduced ossicles
  • The Concentricicloids: Two concentric water vascular rings
• What are the general characteristics of echinoderms?

  • 6,500 living species
  • 13,000 fossil species
  • Mostly marine
  • Radially symmetric adults
  • Lack cephalization
  • Well-developed internal skeleton
• What are the functions of tube feet in echinoderms?

  • Locomotion
  • Food collection
  • Gas exchange
  • Site of excretion
  • Chemoreception
• What are the reproductive characteristics of echinoderms?

  • Gonochoric
  • External fertilization
  • Asexual replication possible
• What are the main features of the digestive system in echinoderms?

  • Mostly complete except for Ophiuroidea and Concentricicloids
  • Tubular digestive system in Crinoidea
  • Autotomy in some species
• What are the characteristics of the nervous system in echinoderms?

  • Developed ectoneural system
  • Addition of hyponeural system in Stelleroidea
• What are the characteristics of the circulatory system in echinoderms?

  • Hemal system present
  • True heart is absent
• What are the characteristics of the excretory system in echinoderms?

  • None in adults
  • Cilia-driven nephridial system in larvae
• What are the characteristics of the respiratory system in echinoderms?

  • Primarily diffusion
  • Papulae and respiratory trees
• What are the characteristics of Class Crinoidea?

  • Fossil records date back to 600 million years
  • 100 species of stalked lilies
  • 600 species of feathered stars
  • Suspension feeders
• What are the characteristics of Subclass Ophiuroidea?

  • Well-developed ossicles in arms
  • Snake-like movement of arms
  • Mostly deposit feeders
  • Can easily detach arms
• What are the characteristics of Subclass Asteroidea?

  • Gonads and digestive tract extend into arms
  • 1900 species
  • Prey on larger invertebrates
• What are the characteristics of Class Echinoidea?

  • 1000 species
  • Possess spines for protection
  • Tube feet as light receptors
• What are the characteristics of Class Holothuroidea?

  • Worm-shaped body
  • Lacks arms
  • Soft-bodied and bilaterally symmetric
  • Can expel internal organs (evisceration)
• What are the characteristics of The Concentricicloids?

  • Water vascular system with two concentric rings
  • Tube feet arranged circularly