BIOL 2325 Lecture Notes - Lecture 4: Body Cavity, Gas Exchange, Brachiopod
Document Summary
Crown of tentacles covered with cilia borne on a ridge or fold of body wall. Thin ciliated walls used as respiratory surface. Free swimming feeding larval stage with a ring of large ciliated cells in front of mouth. Attach to bristles with an adhesive disc. Mouth leads to u-shaped gut ending with anus outside ring. Similar to hydroid cnidarians except tentacles ciliated and roll inward. Mostly marine growing on shells and algae. Mouth and anus both exit within the circle of tentacles. Encrust shells, rocks, mangrove roots, ship bottoms. Lophophore is extended and tentacles spread out like a funnel, water is drawn in by cilia and food is trapped in mucus in funnel and drawn into mouth. Undergo budding to produce statoblasts that contain germinative cells. Attach to substrate directly or by fleshy stalk. 2 classes: articulata(connecting hinge with interlocking tooth and socket) and inarticulata(held together by muscles) Ciliary water currents carry food particles over the lophophore.
