The document discusses the phylum Echinodermata, which includes sea stars, sea urchins, sea cucumbers, and crinoids. Echinoderms are radially symmetric as adults and have a water vascular system instead of a circulatory system. This water vascular system allows them to move, feed, and exchange gases via tube feet that extend from their bodies. The four classes of echinoderms are discussed: Asteroidea (sea stars), Echinoidea (sea urchins), Holothuroidea (sea cucumbers), and Crinoidea (crinoids/sea lilies).
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.
