BI256 Lecture Notes - Lecture 1: Spongin, Pedal Disc, Isospora
Document Summary
New design for living: cambrian explosion (500 mya, 34 major phyla of living multicellular animals with a distinctive body plan, body plan: Regular arrangement of body structures relative to axis of the body. Animals can be bisected along at least one plan. Body plans: animal symmetry: asymmetry, no body axis and no plane of symmetry, ex. Protozoan (amoeba), poriferans (sponge) infinite number of planes of symmetry: spherical symmetry. Best suited for floating and rolling: radial symmetry. Body has the general form of a cylinder (e. g. tubular, vase or bowl shaped rare, found only in protozoans (radiolarians) found in some sponges, polyps, hydra): bilateral symmetry. Animals can be divided along a sagital plane into 2 identical portions (left & right) Surfaces differentiate as dorsal (protection) and ventral (locomotion) A variety of descriptive terms are used to describe orientation in bilateral animals. Hierarchical organization of animal complexity (a (b (c (d (e (a)protozoa.
