By:
Shivani
Reshma
Shefali
Valeri
 They
have a water vascular system, a
network of hydraulic canals branching into
extensions called tube feet (function in
locomotion, gas exchange, and feeding)
 There
are 6 classes
 Asteroidea (Sea stars)
 Ophiuroidea (Brittle stars)
 Echinoidea (Sea urchins and Sand
dollars)
 Crinoidea ( Sea lillies and Feather
stars)
 Holothuroidea (Sea Cucmbers)
 Concentricycloidea (Sea Daises)
3



Germ layers
Outer Ectoderm
Middle Mesoderm
Inner Endoderm
 While
the adult enchinoderms has radial
symmetry, the larval stage has Bilateral
symmetry
 There bodies are distributed around the
center
Echinodermatas
are
coelomates
Coelom- A body cavity
that has a mesodermal
lining
A
short digestive tract that
runs from the bottom of
the central disk to the anus
of the top disk.
 Digestive glands secrete
digestive juices and aid in
the absorption and storage
of nutrients
 cephalization
is not presented in
Echinoderms
 they have a disperse network of nerves and
neurons that consist of a neural ring around
the mouth and the radial nerves that follow
the pentaradial structure of the body.
There
is repeated
segmentation
 Endoskeleton-
An internal supporting
skeleton, derived from the mesoderm, that is
characteristic of vertebrates and certain
invertebrates.
 5 part body organism
 Each tube foot consists of a bulb like
ampulla and a podium (foot portion)
 As it moves it excretes a chemical so that is
how it leaves its “footprints”
 echinoderms
don’t have well-defined
respiratory systems (with the exception of
the holothurian group)
 Echinoderms don’t have well-defined
circulatory systems.
 The ambulacral hydrovascular system takes
the role of both these system’s functions.
 Involves
separate male and female
individuals that release their gametes into
the water.
 Echinoderms
are marine animals, they live in
salt water.
 They also inhabit coral reefs, mangroves, and
sea grass, and soft bottom areas.