BI236 Lecture Notes - Lecture 7: Symmetry In Biology, Rotifer, Gastric Glands
Document Summary
Biology bi256 life on earth : animals; gnathifera, ectoprocta and nemertea. Excretory system has pair of protonephridial tubules with flame cells that empty to common bladder. Pulsating motion drains bladder into cloaca which also serve intestines and oviduct. Osmoregulation is important in both freshwater and marine species; because water enters by the mouth during feeding. A bilobed brain is dorsal to the mastax with paired nerves leading off to the organs. Sensory organs include eyespots, sensory bristles and papillae, and ciliated pits and dorsal antennae. Draws food towards the mouth and sort out larger unsuitable particles in suspension feeders. The mastax is a muscular pharynx equipped with hard jaws, the trophi. Trappers have a funnel-shaped area around the mouth; side lobes fold inward to entrap prey. Salivary and gastric glands secrete enzymes for extracellular digestion. Rotiferans are dioecious with males being smaller than females which contain combined ovaries and yolk glands.
