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.