Choanoflagellates Fungi ANIMALIA Choanoflagellates Porifera (sponges) ANIMALIA Multicellularity Ctenophora (comb jellies) Cnidaria (jellyfish, corals, sea anemones) Diploblasty Acoela (acoels) LOPHOTROCHOZOA Rotifera (rotifers) Loss of coelom Platyhelminthes Triploblasty (flatworms) Segmentation Annelida (segmented worms) PROTOSTOMES Protostome Mollusca BILATERIA development (snails, clams, squid) ECDYSOZOA Nematoda (roundworms) Cephalization, CNS, coelom Arthropoda Segmentation (insects, spiders, crustaceans) DEUTEROSTOMES DEUTEROSTOMES Radial symmetry Echinodermata (in adults) (sea stars, sand dollars) Deuterostome development Chordata Segmentation (vertebrates, tunicates) PHYLUM ECHINODERMATA Echinoderm Characteristics • Coelomate, Triploblastic • Deuterostome • Loss of Cephalization • (Penta)radial Symmetry (secondary) • Water vascular system • Calcareous ossicles/Endoskeleton • Spines (calcareous) • Mutable connective tissue • All Marine (or estuarine) Pisaster ochraceus Ossicles Madreporite Cross-section of Sea Star Arm Asterina miniata Sea Star Water Vascular System Figure 20_01 Sea Star Oral View Tube feet (podia) in motion Pisaster brevispinus PHYLUM ECHINODERMATA Class Crinoidea Class Stelleroidea Subclass Asteroidea Subclass Ophiuroidea Class Echinoidea Class Holothuroidea Class Crinoidea Florometra serratissima Florometra serratissima A fossil crinoid Subclass Asteroidea, Blood star, Hencricia levisuscula Sea Star internal organs Anatomy of a sea star * * * * * Vertical section through central disc and base of arm Pisaster giganteus Dermasterias imbricata Pisaster giganteus Linckia columbiae Subclass Ophiuroidea Ophioplocus esmarki, a brittle star Ophiothrix spiculata Ophiothrix spiculata Class Echinoidea Strongylocentrotus purpuratus, a sea urchin Sea urchin pedicellariae and other body wall structures pedicellariae Arbacia sp. Urchin Test Class Echinoidea Sea Urchin Aristotle’s lantern Figure 20_16 Strongylocentrotus franciscanus Dendraster excentricus Lovenia cordiformis Class Holothuroidea Release of cuverian tubules Figure 20_20 Eupentacta quinquesemita Eupentacta quinquesemita Parastichopus parvimensis Parastichopus californicus Parastichopus californicus .