BIOL-2111 Study Guide - Medulla Oblongata, Viviparity, Inferior Vena Cava
2 May 2014
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2. 1 vertebrates in relation to other animals: protostomes- only have the blastopore opening to the body (ex. Arthropods, annelids, etc. : deuterostomes- form a second opening during embryonic development allowing for a mouth and an anus (ex. Urochordates and cephalochordates are the only extant non-vertebrate chordates. Due to their soft bodies, it is hard to preserve them in fossils and thus hard to establish a clear lineage. They lack kidneys, but vertebrates and amphioxus share excretory cells called podocytes and amphioxus have a vertebrate-like tail fin. Cambrian chordates: best known early chordate-like animal- pikaia that had myomeres and a notochord running across 2/3 of the body. Vertebrae may be made of bone or cartilage. However, not all animals included in the traditional subphylum vertebrata have vertebrae. Two embryonic features may account for many of the differences between vertebrates and other chordates:
