SmallLophotrochozoansSlides

SmallLophotrochozoansSlides - 9/20/11 PROTOSTOMES (see...

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9/20/11 1 “SMALL LOPHOTROCHOZOANS & SMALL ECDYSOZOANS” 5 th edition: chapter 9 and pp. 222-230 of chapter 12 4 th edition: chapter 9 and pp. 263-266 of chapter 13 “PROTOSTOMES” “LOPHOTROCHOZOA” “ECDYSOZOA” -acoelomates (last week & today) -pseudocoleomate, & coelomate phyla (today) “Gnathiferans”: Phyla Gnathostomulida Micrognathozoa (monotypic) *Rotifera *Acanthocephala *Phylum Gastrotricha *Phylum Cycliophora (1995) *Phylum Entoprocta *Lophophorate phyla: Ectoprocta, Brachiopoda, Phoronida 5 th ed.: Chapter 9 some of the “smaller phyla” today trochophore larva (most) possess a lophophore (some) (see inside of text cover) Lab manual puts in Ecdysozoa PROTOSTOMES LOPHOTROCHOZOA ECDYSOZOA acoelomate (last week & today) pseudocoleomate, & coelomate phyla (today) some of the “smaller phyla” today Pseudocoelomate Phyla: *Nematoda *Nematomorpha Kinorhyncha Priapulida Acoel/Pseudo: Loricifera external cuticle is molted as organism grows 5 th ed.: p222-230 4 th ed.: p263-266 text inside cover: 10 lophotrochozoan phyla 5 th ed.: Chapter 9 an evolutionary “ grade ”: - a group that shares the same level of organization &/or similar features, but not necessarily a common ancestor et al… the pseudocoelomate “grade” Ectoprocts
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9/20/11 2 Pseudocoelomate - cavity derived from blastocoel (not from within mesoderm), so not enclosed entirely by mesoderm & hence, not a true coelom. Platyhelminthes & Nemertea (acoelomate) In pseudocoelomate taxa, the original blastocoel of the embryo persists as a space or cavity between the gut and the body wall. Fig. 9.1 (4 th: 9.2) * The pseudocoelom may be filled with fluid or gelatinous material with mesenchyme cells. It generally provides greater freedom of movement & hydrostatic support (the cavity is a base for mesodermal muscles that provide movement) There is now space for more development of digestive, excretory, and reproductive systems (vs. acoelomates). Lab manual : lists 7 distinct phyla as belonging to the pseudocoelomate grade ( Rotifera, Acanthocephala, Gastrotricha, Nematoda, Nematomorpha, Kinoryncha and Ectoprocta ) - some new phyla discovered since manual was written - some taxonomic revision/controversy Text covers…
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9/20/11 3 Chapter 9: ten lophotrochozoan phyla Fig. 9.2 * * * * * * * * -some are acoelomate -some are pseudocoelomate -some are coelomate (new edition) = 7 phyla covered in class today Features shared by most (or all) of these lophotrochozoan phyla: Triploblastic protostomes ; usually small size complete gut (only Acanthocephala lack gut): separate mouth, anus “most” with a pseudocoelom - closed fluid-filled sac with multiple functions: (1) hydrostatic “skeleton” ; (2) “open” circulation (no blood-vascular system); (3) contains organs for reproduction & osmoregulation ( most phyla have protonephridial excretory system) a few coelomate phyla an a cellular outer body covering: a cuticle ( most phyla) made of
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This document was uploaded on 11/03/2011 for the course BSC2011L BSC2011L at FSU.

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SmallLophotrochozoansSlides - 9/20/11 PROTOSTOMES (see...

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