Download Phylum Echinodermata

Phylum Echinodermata
Echinoderms =“Spiny skinned”
General Characteristics
 Examples: sea stars, sea urchins, sand dollars, and sea
cucumbers
 Can regenerate limbs if part of
central disk attached.
 Organ system
•Pentaradial Symmetry
(adults)
•Body parts arranged
into groups of 5
around a central axis
•Bilateral Symmetry
(larva)
Water Vascular System
• Network of water
filled canals
• Water is pushed in
and out of the system
enabling the
echinoderm to move
• locomotion,
attachment, one part
sensory system, gas
exchange,
Water Vascular System con’t
•
•
Path of the water:
Madreporite Stone Canal Ring Canal Radial Canal Ampulla
Tube Feet
•
Ampulla: muscular bulblike sac connects to tube feet
Asterias dissection 1
Oral surface
Aboral surface
Return to axonomy
Asterias dissection 2
 Aboral surface removed.
Asterias dissection 3
 Aboral surface
removed.
Asterias dissection 4
 Aboral surface,
stomachs and some
pyloric caeca
removed
Asterias dissection 5
 Aboral surface,
stomachs and some
pyloric caeca
removed
Urchins
 Feed on algae,
corals, dead animal
remains
 Aristotle’s
Lantern: complex
jaw-like mechanism
that is used to grind
their food (found in
urchins)
Sea Cucumbers
How they feed: tentacles around the
mouth sweep up sediment from the
water
Sea Cucumbers
 Defense:
 Evisceration: Eject internal organs through the anus
 The organs contain toxins that immobilize prey