BIOL 112 Chapter Notes - Chapter 7: Animal, Ecdysozoa, Eumetazoa
9 Jan 2017
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Supergroup=unikonta: synapomorphy from plants=lack of chloroplasts. 10/18/16: heterotrophs, multicellular euk; lack cell walls, specialized cells=unique (except sponges, mainly sexual w/dom diploid (2n) stage. Poriferans=basal animals; lack true tissues and usually asymmetrical. Sponges: reproduce asexually by budding and fragmentation, sexual=serial hermaphrodites, sedentary lifestyle, filter-feeding cell=choanocyte, taxa. Calcarea: *glass sponge, skeletons made of silica, calcite, or sponging, 3 body forms. Single opening in gastrovascular cavity=both mouth and anus. Hydrozoans: dom polyp stage: obelia, hydra: lacks medusa stage. Scyphozoans-jellies: dom medusa, radial canals, statocysts, biologically immortal, slide=aurelia. Anthozoans: only polyps; asexual or sexual repro: sea anemones, corals, and sea fans, bilateria: bilaterally symmetrica; triploblastic; 3 diff. body plans: acoelomate, pseudocoelomate, or colemate. Ecdysozoa=1st branch of protostomes schizocoelus, spiral cleavage, determinate cell division, blastospore mouth: nematodes and arthropods, ecdysis; triploblastic=3 tissue/germ layers (acoelomate, pseudocoelomate, coelomate, phylum nematoda: pseudocoelomate. Chelicerata: 6 pairs of appendages, chelicerae, cephalothorax, ab. trilobites=good fossil; hypostome. 1 pair of antennae and 3 pairs of modified appendages.
