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Unformatted text preview: I. An introduction to protostomes A. Who are these guys? 1. Morphology a. ~20 phyla, most marine and most with The Big Two b. Arthropods exoskeleton: segmented body: jointed limbs: c. Molluscs muscular foot: visceral mass: mantle: Question: Why do arthropods and mollusks have a drastically reduced coelom? 2. Phylogeny Two major lineages of protostomes: Ecdysozoans: grow by molting Lophotrochozoans: may have feeding apparatus called a lophophore and trochophore larvae (distinctive morphologically) B. Whats cool about protostomes? Water-to-land transition: multiple events Arthropods Molluscs Roundworms Annelids Metamorphosis Question: What is the adaptive significance of holometabolous metamorphosis?...
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