Echinoderms

Spiny-skinned Interlocking spines and plates with calcium carbonate Interlocking spines and plates with calcium carbonate Sea stars, brittle stars, sea urchins, sea cucumbers, sand dollars Sea stars, brittle stars, sea urchins, sea cucumbers, sand dollars Radial with few bilateral features Radial with few bilateral features Larvae are bilateral Larvae are bilateral Bottom dwellers, but most creep about Bottom dwellers, but most creep about

Sexual reproduction Sexual reproduction External fertilization External fertilization 5-fold Radial symmetry 5-fold Radial symmetry Coelomate Coelomate Lack of Segmentation Lack of Segmentation

Nervous System Decentralized Decentralized No concentrated area for a brain No concentrated area for a brain No head No head

Water-Vascular System Short side canals deliver water to tube feet Short side canals deliver water to tube feet Inside foot = bulb contracts causes foot to lengthen Inside foot = bulb contracts causes foot to lengthen coordinated coordinated

Fig , p. 451 upper stomach anus lower stomach spine ossicle ossicle (stiffening, support structure) gonad coelom digestive gland eyespot spine part of the water-vascular system Phylum Echinodermata: Systems  Water vascular system and tube feet provide for locomotion, feeding and sensory reception  Complete digestive system  Nervous system