Introduction Echinoderms and chordates are deuterostome animals that possess an endoskeleton. The echinoderms have evolved radial symmetry from an ancestor with bilateral symmetry. These organisms inhabit intertidal and subtidal habitats.
Some species live at the bottom of the ocean.
The chordates show a remarkable diversity of form and function, ranging from the sessile sea squirts to salmon, eagles, elephants, and humans. However, chordates share several features that have been very important in their evolution. Free-swimming bilaterally symmetrical larval stage present. Class Asteroidea- Sea Stars. Closed ambulacral grooves .