What kind of fish swims in the
sky at night?
Starfish
Echinoderms
Phylum Echinodermata
“Spiny skin”
• All Marine
• CaCO3 in skin and shell (test) bumpy skin
• Papilla increase surface area, breathe through
skin
• Secondary radial symmetry
• Planktonic larva are bilaterally symmetrical
• Radial symmetry is pentamerous (5 sided) (no
anterior/ posterior, dorsal, or ventral but oral vs..
aboral).
• Endoskeleton (sea urchin test)
• Unique water vascular system, muscles
squeeze water into and out of tube feet,
which, ends in suckers for attachment and
movement.
• Pedicellariae - pincers to keep surface clean
Class Asteroidean Sea stars: 1700 species (carnivores)
• Sometimes have 50 arms that can be
regenerated.
• Predators of bivalves and snails, force open,
invert stomach into or on, then digest
outside of body.
Class Ophiuroidea snake like: 2000 species
• Central disc body, move by wringing their arms.
• Arms break off easily and regenerate.
• Detritivores and suspension feeders.
• Basket stars have highly branched arms.
Class Echinoidea
(herbivores)
Sea urchins/ Sand dollars:
• Endoskeleton forms a “test” holes for
tube feet, knobs for spine attachment.
• Have moveable spines and tube feet for
locomotion.
• Aristotle’s Lantern is a system of muscles that
controls the five teeth.
• Graze on attached or drifting plant material.
Class Holothuroidea
Sea cucumbers: 900 Species (Detritivore)
• Worm like echinoderms, mouth to anus is
stretched.
• Detritivore - deposit feeder with modified tube
feet as tentacles to move food into mouth.
• Evisceration - release guts/ internal organs out
the anus as defense.