BIO 181 NCSU Unit 3 Review – Biodiversity, Exam Questions and answers. 100% Accurate. VERIFIED.

BIO 181 NCSU Unit 3 Review – Biodiversity, Exam Questions and answers. 100% Accurate. VERIFIED. Intracellular digestion - -type of digestion in which food is digested inside specialized cells that pass nutrients to other cells by diffusion Extracellular digestion - -type of digestion in which food is broken down outside the cells in a digestive system and then absorbed Germ Layers - -ectoderm, mesoderm, endoderm Endoskeleton - -- under epidermis - increased mobility Exoskeleton - -- outside epidermis - hard protective layer made of chitin - organism has to shed its skin ( molt ) in order to grow, restricts growth Hydroskeleton - -Fluid filled cavities provide structural support. Symmetry - -Radial: - sessile/floating animals - allows sensory input from all directions Bilateral: - moving through environment - associated with cephalization - sensory input/direction Cephalization - -Concentration of neurons and sensory structures in head region, ectoderm Segmentation - -The division of the body of an organism into a series of similar parts - used for movement/modification Circulation - -Diffusion: no specialized structures to distribute nutrients/waste - very small organisms Open Circulation: Fluids pumped around a cavity - fluid and blood mix, dumped into body cavity Closed Circulation: Blood pumped through vessels - pure blood, stays within veins/arteries 11 Phylums to Know - -Porifera Cnidaria Platyhelminthes Rotifera Mollusca Annelida Nematoda Arthropoda Echinoderms Chordata Porifera (sponges) - -- no symmetry - no nerve or muscle tissue - sessile - filter nutrients from H2O drawn into a central cavity - ectoderm and endoderm - spicules: internal structural support Cnidarians (jellyfish) - -- predominately marine species - ectoderm and endoderm - incomplete digestive tract (body cavity) Platyhelminthes (flatworms) - -- cephalization - incomplete digestive tract - most simple organism with bilateral symmetry Rotifera (rotifers) - -- "wheel animals" - complete digestive system - diverse, found in all habitats - primary consumers - bioindicators: reflect qualities of the environment Mollusca (Snails, Bivalves, and Octopi) - -- bilateral symmetry - complete digestive tract - mantle and foot in commo