topic13 - BIOL 1030 TOPIC 13 LECTURE NOTES Topic 13:...

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BIOL 1030 – TOPIC 13 LECTURE NOTES Topic 13: Lophotrochozoans (Ch. 33) I. Lophotrochozoa clade includes the following phyla that we will cover: 1. Ectoprocta (or Bryozoa; clade) 2. Platyhelminthes (clade?) 3. Rotifera (clade) 4. Annelida (clade) 5. Nemertea (clade) 6. Brachiopoda (clade?) 7. Phoronida (clade) 8. Mollusca (clade) II. Phylum Ectoprocta (bryozoans, or moss animals) A. ~4500 living species B. coelomate C. aquatic, mostly marine D. use lophophore for feeding E. secrete and live in a chitinous chamber ( zoecium ); also may be reinforced with calcium carbonate F. adults are sessile and colonial; communicate chemically through pores in zoecia G. some non-protostome characteristics: radial cleavage, secondary mouth, deuterostome-style coelom H. appear to be a sister group to rest of the lophotrochozoans III. Phylum Platyhelminthes – the flatworms (must exclude Acoelomorpha to have any hope of having a grade or clade; acoelomorphs are interesting though, feel free to look up information about them on your own) A. ~20,000 living species B. acoelomate C. ribbon-shaped, soft-bodied, flattened D. most are parasitic, some are scavengers and carnivores E. non-parasitic forms far more active than cnidarians or ctenophores F. those with a digestive cavity have an incomplete gut (only one opening) G. excretory system - small tubules lined with ciliated flame cells (move water and waste into tubules and out of body) H. no circulatory system – oxygen and food must diffuse to all cells I. some have nerve cords and simple central nervous system J. reproduction 1. most are hermaphroditic 2. most have internal fertilization: each partner deposits sperm in the other’s copulatory sac 3. asexual regeneration also possible in many K. three classes to learn (we’ll leave out the 4 th class, Monogenea) L. Class Turbellaria (grade) 1. only free-living flatworms 2. use ciliated epithelial cells for movement 3. have eyespots; usually move away from light 4. have sensory pits or tentacles for detecting food, chemicals, and nearby movement 5. use pharynx (muscular throat) in feeding 6. abundant in many aqueous environments 7. some occur in moist terrestrial areas 8. include planaria M. Class Trematoda (clade) – flukes 1. all parasitic; resistant to digestive enzymes and host immune responses 2. use mouth to feed 3. 1 mm to 8 cm long 4. attach via suckers, anchors or hooks 5. usually have two or more hosts (larvae almost always in snails, final host almost always a vertebrate) 6. important pathogens of humans: human liver fluke inhabit bile passages in the liver of humans, cats, dogs, and pigs can get them from eating raw fish 1 of 6
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BIOL 1030 – TOPIC 13 LECTURE NOTES can cause cirrhosis and death in high infestations blood flukes of genus Schistosoma afflict 5% of world’s human population and cause schistosomiasis (kills ~800,000 each year) N. Class Cestoda (clade) – tapeworms 1. all parasitic; resistant to digestive enzymes and host immune responses
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topic13 - BIOL 1030 TOPIC 13 LECTURE NOTES Topic 13:...

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