BIOL 2P92 Final: Chapter 14 - Chaetognaths, Echinoderms and Hemichordates
13 Apr 2016
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Triploblasic divided into two large clades: protostomia. Formaion of the mouth from embryonic blastopore (protostomy) When coelom is present: marine annelids and molluscs, deuterostomia. : arrow worms planktonic small bodies unsegmented bodies caudal in body covered with thin cuicle. 2 deuterostome phyla: phylum echinodermata, phylum hemichordata. Sea lilies: calcareous, spiny endoskeleton plates/ossicles, water-vascular system, pedicellariae, small claw shaped appendage w. moveable jaws (valves, dermal branchiae, basic pentaradial symmetry. Tube feet (podia: project from ambulacrum; ambulacra extend from mouth along oral sides of each arm to its ip, ambulacral groove occurs along middle of each ambulacrum. Open in asteroids and crinoidea; closed in other groups. Bordered by moveable feet: radial canal of water-vascular system, aboral side; rough & spiny. Has anus and madreporite: madreporite: aboral side of sea star (echinoderms) calcareous sieve that leads to water-vascular system. Endoskeleton and coelom under epidermis of sea star: small calcareous plates/ossicles catch collagen, liquid solid.
