ZOO 2700 Lecture Notes - Lecture 7: Glycerol, Chitin, Vertically Transmitted Infection
28 Mar 2018
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Document Summary
Laumer proposed that placozoans are (cid:498)eumetazoans(cid:499) related to cnidaria. Added new genome assemblies from three members of previously unsampled placozoan lineages (cryptic species) At-rich placozoa may cause artefacts in phylogeny due to reductions in amino acid heterogeneity (cid:498)eumetazoa(cid:499) Traditional taxon (not in dunn or online phylogeny: all animal groups except sponges and placozoa, ctenophora, cnidaria, bilateral. Characteristics: body symmetry: radial, bilateral, epithelial tissue, gut, muscles, nerves. Covers surfaces and lines internal cavities and spaces. Allows physiological compartmentalization: polarised (basal facing other cells, apical facing environment, continuous layer, basal lamina, intercellular junctions, evolved into muscle and nerve. Apomorphies: stinging cells (cnidocytes, polyp adult and planula larva, nerve nets, longitudinal and circular muscle, endodermal gonads, circular mitochondrial dna (anthozoans) and linear mtdna. A molecular phylogeny of the cnidaria, overlaid with key synapomorphies of the major lineages. Predation likely threats juvenile stages of the jellyfish life cycle. Baby lobster with a taste for jellyfish surfing.
