echinodermata

• What type of environments do echinoderms inhabit?

  All marine environments
• What is the primary ecological role of echinoderms?

  They may be predators, filter feeders, scavengers, deposit feeders, or browsers
• What is a unique feature of echinoderms related to their skeletal structure?

  They possess a calcareous endoskeleton
• What is the function of the water-vascular system in echinoderms?

  It aids in locomotion, food gathering, respiration, and excretion
• What are pedicellariae in echinoderms?

  Forceps-like organs that keep the body clean and capture food
• How do dermal branchiae function in echinoderms?

  They are projections of the coelomic cavity that function in respiration
• What type of symmetry do echinoderms exhibit?

  Pentaradial symmetry
• What does the term "enterocoelous" refer to in echinoderms?

  It refers to the extensive coelom forming the perivisceral cavity and the cavity of the water vascular system
• What is the structure of the nervous system in echinoderms?

  It consists of a circumoral ring with radial nerves and few specialized sensory organs
• How do echinoderms reproduce?

  They mostly have separate sexes, with external fertilization and free-swimming bilateral larvae
• What distinguishes Class Asteroidea from other echinoderm classes?

  They have five tapering arms merging with a central disc
• What is the feeding mechanism of Class Asteroidea?

  They have a two-part stomach with a lower cardiac and a smaller upper pyloric stomach
• What is a key characteristic of Class Ophiuroidea?


  They have slender arms sharply set off from the central disc
• How do Class Ophiuroidea locomote?


  They move by arm movement
• What is the primary feeding structure in Class Echinoidea?

  Aristotle's lantern, a complex chewing mechanism
• How do Class Holothuroidea differ from other echinoderms in body structure?

  They are greatly elongated in the oral-aboral axis and lie on their side
• What is autoevisceration in echinoderms?

  It is the ability to eviscerate parts of their internal mass to ward off predators
• What is a characteristic of Class Crinoidea?

  They have a flower-shaped body attached to a long, jointed stalk
• What are the main characteristics of echinoderms?

  • Calcareous endoskeleton
  • Water-vascular system
  • Pedicellariae
  • Dermal branchiae
  • Pentaradial symmetry
• What are the differences between the classes of echinoderms: Asteroidea, Ophiuroidea, Echinoidea, Holothuroidea, and Crinoidea?

  Class Asteroidea:

  • Sea stars with five tapering arms
  • Two-part stomach

  
  

  Class Ophiuroidea:

  • Brittle stars with slender arms
  • Closed ambulacral grooves

  
  

  Class Echinoidea:

  • Sea urchins with a test of ossicles
  • Aristotle's lantern for feeding

  
  

  Class Holothuroidea:

  • Sea cucumbers, elongated body
  • Reduced ossicles

  
  

  Class Crinoidea:

  • Sea lilies and feather stars
  • Flower-shaped body with stalk