BIOL 2030 Lecture Notes - Lecture 14: Cloaca, Peritoneum, Pearlfish
Document Summary
1: body form and function, water-vascular system, osmoregulation, respiration, introduction. Subphylum eleutherozoa: class asteroidea seas stars, class ophiuroidea brittle stars, class echinodea sea urchins, sand dollars, class holothuroidea sea cucumbers. Predator left to eat organs while sea cucumber crawls away: free living (not sessile) animals. Cephalization absent; no anterior or posterior ends: no brain-like structure. Body surfaces are designated as either oral (bearing mouth) or aboral (no mouth: asteroidea, oral surface. Perivisceral coelom present in both: not a lot of room in the arm of a brittle star, more space in sea star and more structures in the space, no organs in the arms of the brittle star. Ambulacral groove: ambulacral ossicles in sea star, radial canal in both (part of water vascular system, no radial nerve in brittle star but hyponeural and ectoneural nerves. Vertebrae large white structure in center of the arm. Muscle runs along the length of the arm (both)
