class asteroidea pedicellariae tiny pincher-like organs on the aboral side keep the surface clean...
Post on 31-Dec-2015
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Class Asteroidea• Pedicellariae • Tiny pincher-like organs
on the aboral side keep the surface clean
• Most sea stars are predators of bivalves, snails, or other attached or slow moving animals
Class Ophiuroidea• Includes: Brittle Stars• Legs proportionally
longer and thinner than sea stars
• Allows for better movement
• Organs in central disc• Tube feet lack
suckers
Class Ophiuroidea
• Eat organic matter and small animals they find on the bottom
Class Echinoidea
• Includes: Sea Urchins & Sand Dollars
• Body structure forms a round, rigid body with movable spines and pedicellariae
• Locomotion achieved by movable spines
Class Echinoidea• Body plan of sea stars
repeated by moving arms upward and connecting them at the tips
• Mouth is on the bottom, anus on the top
• Spines: sharp, hollow and sometime contain venom
Plates:
• 10 plates• Alternating abulacral
(have openings for tube feet) and interambulacral (bumps for spines)
Class Echinoidea
• The mouth has an intricate system of jaws and muscles called Aristotle’s Lantern
• Used to bite off algae and other bits of food from the bottom
Class Echinoidea
• Heart Urchins and Sand Dollars are adapted for the soft bottom of the ocean
• Flat bodies and short spines
Class Holothuroidea
• Sea Cucumbers• Similar body plan to
a sea urchin, just stretched out from mouth to anus
• Lies on sides, oral and aboral surfaces are at the ends
Class Holothuroidea• Most have five rows of
tube foot that run mouth to anus
• Some excrete toxic substance as defense mechanism
• Some expulse gut and other internal organs out of the mouth or anus, called evisceration
• Believe that they grow the organs back
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