1. Phylum Echinodermata

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Characteristics
Echinodermata means “spiny skin”
usually inhabit shallow coastal waters and ocean trenches
lack body segmentation and cephalization
most adults have five-part radial symmetry
more than 5000 species of Echinoderms.
Include sea stars, sea urchins, sea cucumbers, sand dollars.
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3. Examples:
Sea Stars
Sea Cucumbers
Sea Lilies
Sand Dollars
Sea Urchin

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Change from a bilateral, free-swimming larva to a bottom-dwelling adult with radial symmetry
Their skin is stretched over an endoskeleton (internal skeleton formed of hardened plates).
made up of calcium
may include protruding spines
Have small feet called tube feet that aid in movement, feeding, respiration, & excretion.
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5. Digestion Simple one way digestive system
Sea Stars: pry open molluscs using their tube feet and then throw their own stomachs out into the shell to digest the meat before it’s brought back into its body!
Sea Urchins: scrape algae from rocks
Sea Cucumbers: move over ocean floor feeding on detritus
Sea Lilies: use tube feet to capture floating plankton

6. Have water vascular system which carries out respiration, circulation and excretion.
Circulation: No real circulatory system
diffusion through tube feet
circulates by water vascular system
Respiration: Diffusion through gills and tube feet
Excretion:
Digestive waste is released as feces through the anus.
Cellular wastes by diffusion through gills and tube feet

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Nervous system: Primitive nervous system; no head/brain
Nerve net controls tube feet and spines.
Capable of some more complex behaviours
Reproduction:
Mostly separate sexes
sexually and asexually (by regeneration)
External fertilization
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