BIOL 125 Lecture Notes - Lecture 8: Actinopterygii, Water Vascular System, Pharyngeal Jaw
20 Mar 2017
School
Department
Course
Professor
Document Summary
Endoskeleton - calcium carbonate secreted into skin, inside thin layer of epidermal tissue. Water vascular system- tube feet = fluid filled appendages, podia= tube feet outside body. Used for movement, version of circulatory system, using water as blood. Changes hydrostatic pressure of podia to grab food and move. Synapomorphies (radial symmetry, endoskeleton, water vascular system) identify as monophyletic group. Pedicellariae - modified ossicles for feeding/cleaning, look like jaws. Ambulacrum - moves food from one place to another (down arms) b) Ophiuroidea (brittle & basket stars) origin from snakes - ophidian. No pedicellariae, no papulae, no anus, no suckers on tube feet. Articulated ossicles - move quickly, tube feet everywhere. Pouches between arms for production and gas exchange. 5 or more long arms, suspension feeders, mucus, capture prey c) Mucus membrane with cilia brings food to mouth e) Bilateral symmetry, suspension/deposit feed with tentacles around mouth. Respiratory tree - everted when scared as defense.
