Starfish –Phylum
Echinodermata
Starfish Dissection
Aboral surface
Oral surface
Mouth
shell
Madreporite is opening of the water
vascular system
Tube feet are the terminal end of the
water vascular system
Starfish Dissection
ampulla
shell
Starfish can evert their stomach
through their mouths and begin
digestion of the prey outside the body
Gonads may be big or small
depending on season
Starfish Dissection
Water Vascular System
Radial canals in
each ambulacral
ridge
Ring
Radial canals in
canal
each ambulacral
ridge
ampulla
Water comes in the
madreporite, travels through
the stone canal to the ring
canal and then flows through
the radial canals in each arm.
The short transverse canal
connects the radial canal with
the ampulla. When the
ampulla fill with water, they
contract and move the tube
feet.
Phylum Echinodermata (means spiny skin)
Crinoidia – sea lilies
Echinoidea – sea urchins and
sand dollars
Asteriodia – sea stars = starfish
Opiuroidea – brittle stars
Holothuroidea – sea cucumbers
Phylum Echinodermata
Habitat: marine
Symmetry: Bilateral larva, radial symmetry in adults
Body Cavity: coelomate
Development: Deuterostome
Skeleton: spicules embedded in dermis or a
calcareous endoskeleton
composed of spines/ossicles