Slide 1 Our first group of deuterostome animals are the echinoderms - represented by the sea stars and sea urchins. It may seem odd - but this group of organisms is most closely related to us than any group we have discussed thus far. We recognize the close evolutionary relatedness because we share a deuterstome mode of development.
Slide 2 Phylum echinodermata consists of the sea stars, sea urchins, sea cucumbers, brittle stars, and feather stars. Notice that as adults these organisms have a radial symmetry - but they are members of the bilateria. While they are radial as adults - they are bilateral as larvae. This group of organisms has an endoskeleton and a unique mode of motility involving a water vascular system and tube feet. The water vascular system is a system of canals filled with fluid that connect to the tube feet. The tube feet use hydraulic pressue to expand and contract and move the animal along the sea floor.
Slide 3 This is an exclusively marine group - so while they have evolutionary advanced characters they are still dependent on an aquatic environment.