Echinodermata

Charateristics

Echinodermata- means spiny skined

have spiny skin- skeleton ossicles and pines

Radial Symmetry as adults

bipinnaria larva (free swimming) has bilateral symmetry

dueterostome development

Marine animals

Five parts around central axis

water vasular system- (Hydraulic vasular system)

• opening called madreportite or sieve plate
• set of water-filled canals branching from a ring canal that encircles the gut
• The canals lead to podia, or tube feet,
• which are sucker-like appendages that the echinoderm can use:
  • to move,
  • grip the substrate,
  • Gas exchange
  • or manipulate objects.
• These tube feet are extended and retracted by hydraulic pressure in the water-vascular system.
  

Pedicellaria- clean serface - napper-like skeletal elements that are used by the echinoderm to keep small organisms from settling on its body, and free of debris

• includes dermal gills (skin gills) very small

Mesodermal exoskeleton

• Made of calcium carbonate
• Calcified plates and spines
• Ridged support
  
  
• Circulatory system
  

Complete digestive tube
Radial nervous system- modified nerve net- no central nervous system, but have ganglia
Sexual reproduction- sperm and eggs are released in water where fertilization takes place
Regenerative
Deterostomes- related to chordates (both are deuterostomes)

Echinoidea (echinoids, sea urchins and sand dollars): notable for their movable spines; about 1,000 species.

Starfish dissection

sieve plate- off-center of front side- that connects the water vascular system with the external ocean water
skin gills- for respiration
Tube feet- used for gas exchange, for movement, for opening mollusks
Mouth- center of ventral plate
ampulla- The bulb at the top of the tube foot (it's actually inside the starfish, but it's easier to see this way)
anus- to get rid of waste
Gonad- (looked like humus)- located at the base of each arm under the digestive glands
Coelom- where organs are found
Digestive gland- (looks like Dijon mustard)- pairs of chambered glands
Eyespot- at the tip of the arms or rays
Pyloric stomach- under central plate (no intestine) but there is a small rectal caecae
Rectal caecae- for temporary storage of waste
Pyloric ducts- where digestive enzymes from the digestive gland are carried to the pyloric stomach
Cardiac stomach- on the side of the pyloric stomach- multilobed
ambulacral grooves- connect to tube feet
genopores- which sperm and eggs are released from

Pedicellaria- clean serface - napper-like skeletal elements that are used by the echinoderm to keep small organisms from settling on its body

Test your knowlege of the star fish dissection Here

Phylum Echinodermata bold phylums were mentioned in lab

Subphylum Blastozoa

• Class Eocrinoidea
  
• Class Parablastoidea
  
• Class Rhombifera
  
• Class Diploporita
  
• Class Blastoidea

• Class Crinoidea - sea lilies (crinoids, feather stars or sea lilies): are suspension feeders.
• Concentricycloidea (sea daisies, sea lilies, feather stars), notable for their unique water vascular system; two species; recently merged into Asteroidea.
  
• Class Paracrinoidea

• Class Echinoidea (Sea Urchins) (echinoids, sea urchins and sand dollars): notable for their movable spines; about 1,000 species.
  
• Class Holithuriudea (sea cucumbers): elongated animals resembling slugs
  
• Class Edrioasteroidea
  
• Class Edrioblastoidea
  
• Class Helicoplacoidea
  
• Class Cyclocystoidea

• Class Asteroidea - starfish (asteroids, starfish, or sea stars): species that capture prey for their own food.
  
  
• Class Ophiuroidea - Brittle Stars (brittle stars and basket stars), the physically largest of echinoderms

• Class Stylophora
  
• Class Homoiostelea
  
• Class Homostelea
  
• Class Ctenocystoidea
  

Class Crinoidea - sea lilies

Class Ophiuroidea - Brittle Stars

Class Asteroidea - starfish

Class Echinoidea (Sea Urchins)

Class Holithuriudea (sea cucumbers)

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