1. Phylum: EchinodermataPhylum: Echinodermata
The Spiny-skinned AnimalsThe Spiny-skinned Animals

2. Phylum: Echinodermata
Echino – spiny
Derm – skin
Spiny-Skinned Animals

3. Sea Lily –
Tunicate Cove,
Belize

4. Echinodermata Characteristics
Bilateral as larvae and then Radial as adults
Triploblastic
Complete digestive system
Radial nervous system with no brain
Water Vascular System (no blood)

5. Echinoderms
have a unique
system called
the water
vascular
system. It
allows them to
move, eat, and
exchange gases
with their
environment.
Ring
canal
Radial
canal
Ampulla
Tube Feet
Madreporite

6. Tube feet on sea stars are
located on the ventral
side of the arms. They
can be pulled into slits
called ambulacral
grooves.

7. Tube feet on sea stars are
located on the ventral
side of the arms. They
can be pulled into slits
called ambulacral
grooves. Water is
pumped into the tube feet
from the ampullae (see
previous slide) to cause
the tip of the tube foot to
widen into a suction cup.

8. Tube feet on sea stars are
located on the ventral
side of the arms. They
can be pulled into slits
called ambulacral
grooves. Water is
pumped into the tube feet
from the ampullae (see
previous slide) to cause
the tip of the tube foot to
widen into a suction cup. By moving each tube foot in tiny steps
in a synchronized fashion, echinoderms are able to walk on
them. The steps are so small that the animal appears to be
gliding.

9. Four Classes of Echinoderms
Class: Asteroidea – sea stars

11. Brittle stars have long,
stringy arms. They
move by walking with
their arms. Their tube
feet are like cleats to
provided added traction.

13. Four Classes of Echinoderms
Class: Asteroidea – sea stars
Class: Echinoidea – sea urchins

14. South Water Caye, Belize

16. Four Classes of Echinoderms
Class: Asteroidea – sea stars
Class: Echinoidea – sea urchins
Class: Holothuroidea – sea cucumbers

17. Sea Cucumbers

18. Four Classes of Echinoderms
Class: Asteroidea – sea stars
Class: Echinoidea – sea urchins
Class: Holothuroidea – sea cucumbers
Class: Crinoidea – crinoids/sea lillies