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Mollusca

Mollusca. Paul Ko Andy Zhao Michael Chiu Period 5. http://www.fossilmuseum.net/Tree_of_Life/PhylumMollusca/images/Nautilus-wpd.jpg. 4 Major Classes: Polyplacophora Bivalvia Gastropoda Cephalopoda. http://upload.wikimedia.org/wikipedia/commons/a/a4/Ab_mollusca_01.jpg.

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Mollusca

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  1. Mollusca Paul Ko Andy Zhao Michael Chiu Period 5 http://www.fossilmuseum.net/Tree_of_Life/PhylumMollusca/images/Nautilus-wpd.jpg

  2. 4 Major Classes: Polyplacophora Bivalvia Gastropoda Cephalopoda http://upload.wikimedia.org/wikipedia/commons/a/a4/Ab_mollusca_01.jpg

  3. Class Polyplacophora • Chiton • Marine • Shell with Eight Plates • Foot used for locomotion • Radula • No head http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Mollusca/Polyplacophora/TonicellaLineataDLC1991.jpg

  4. Bivalvia • Clams and oysters • Sedentary or sessile filter-feeding • Marine and Freshwater or Terrestrial • Head reduced • Paired Gills • No radula http://www.korseby.net/outer/fauna/mollusca/bivalvia.jpeg

  5. Gastropoda • Aquatic and terrestrial snails and slugs • Marine, Freewater/terrestrial • Usually has a shell • Foot for locomotion • Radula http://upload.wikimedia.org/wikipedia/en/4/47/Banana_slug_closeup.jpg

  6. Cephalopoda • Predatory cuttlefish, squids and octopi. • Marine • Head surrounded by tentacles • Tentacles usually have suckers • External, internal or absent Shell • Mouth with or without radula http://static.open.salon.com/files/octopus1244124973.jpg

  7. Body Cavities o The body cavities in Mollusca are called mantle cavities (coelom), which are: http://www.southtexascollege.edu/nilsson/4_GB_Lecture_figs_f/4_GB_23_AnimaliaInvert_Fig_f/BodyCavity_Coelom_29A.GIF • Water-filled cavities that house the gills, anus, and • excretory pores. • There are also blood cavities known as hemocoel • which store blood in open-circulatory mollusca.

  8. Body Symmetry • All mollusca have bilateral symmetry meaning… • The organism can be cut in half with the two sides looking more or less exactly the same. • Ex: http://infusion.allconet.org/webquest/PhylumMollusca.html http://chemistry.csudh.edu/faculty/jim/cozaugo4-600/octopus.jpg

  9. Nervous System • Relatively complex nervous system, varies from species to species. • All Mollusca have tentacles that have sensors to detect chemicals, vibrations and touch. • Mollusca have ganglia, a sort of brain-like organ. http://animaldiversity.ummz.umich.edu/site/resources/biodidac/bivanerv.jpg/medium.jpg http://media.photobucket.com/image/cuttlefish/Nephlabobo/ComCuttlefish9.jpg

  10. Circulatory System • Other than cephalopods, all Mollusca have an open circulatory system • These cavities are known as hemocoel, and in mollusks, it has replaced the coelem. • Cephalopods need a closed-circulatory system because their activities require more energy. http://www.esu.edu/~milewski/intro_biol_two/lab__11_mollusca/images/bivalve_circulatory.jpg

  11. Digestive System Radula to scrape up food Digestive tract is complete and ciliated Includes mouth, anus and complex stomach Food is taken up by the digestive glands arising from the stomach, where it is passed into the blood http://kentsimmons.uwinnipeg.ca/16cm05/1116/33-16-MolluskBodyPlan-L.gif

  12. Excretory System • Waste is in solid form so it prevents the fouling of water over gills • Excretory functions are regulated by a pair of nephridia and tubular structures • Collect fluids from coleom and exchanges salts and substances with body tissues during excretion http://awakeningwomen.files.wordpress.com/2009/09/dumbo-octopus.jpg

  13. Locomotion/Musculature • Foot comprised of 3 main body parts • Viceral mass: contains interal organs • Mantle: fold of tissue over visceral mass, includes shell (if present • Mantle Cavity: houses gills and anus and excretory skills • Herbivores are commonly gliders, move on muscular contraction • Carnivores, more advanced locomotion • Cephalopods – Jet Propulsion • Cuttlefish/Sea Hares – Undulating later fins • Bivalves – Foot for burrowing http://www.ck12.org/ck12/images?id=113229

  14. Skeletal System N/A BUT…………………………. They have shells made of calcium carbonate http://www.naturfoto-cz.de/photos/others/roman-snail-21973.jpg

  15. Sensory Structures/Features • Some mollusks have large complex eyes (notably the cephalopods) • Squids can locate and capture transparent prey with specialized polarization vision. http://www.news.wisc.edu/newsphotos/images/Hawaiian_bobtail_squid04.jpg

  16. http://www.dlia.org/atbi/species/Animalia/Mollusca/Gastropoda/images/reproduction/mesomphix_inornaus_DD300.jpghttp://www.dlia.org/atbi/species/Animalia/Mollusca/Gastropoda/images/reproduction/mesomphix_inornaus_DD300.jpg http://www.vattenkikaren.gu.se/fakta/arter/mollusca/bivalvia/ostredul/ostrliv.gif Reproduction • Sexual Reproduction • External Fertilization: Sperm cell is united with egg cell away from the parents. • Trochophore = Larvae • Internal Fertilization Example: Land snails are hermaphrodites. They have a pouch for holding the sperm of the mate. http://www.bobtherieau.com/images/blog/claM.jpg http://www.nicertutor.com/doc/class/bio1903/Locked/media/ch32/32_13Trochophore.jpg

  17. Gas Exchange • Generally takes place in the true gills (ctenidia) • Absorbs the Oxygen from water and diffuses Carbon Dioxide into the water. www.biol.wwu.edu/donovan/biol460/12mollusca.ppt http://kentsimmons.uwinnipeg.ca/16cm05/1116/33-16-MolluskBodyPlan-L.gif

  18. Unique Features • Mantle: Encloses mantle cavity, which circulates oxygen and water. • Radula: The mouth, with teeth bent inwards. Ctenidia Calcium Carbonate Shells http://s3.amazonaws.com/wootdesigncontestentries/Shigwarm/Giant_Squid_vs._Jet_Fighter-f1e6n4-d.jpg http://www.bio.miami.edu/dana/pix/ham.jpg

  19. QUIZ QUESTIONS!! 1. Which of the following phyla do not have symmetry? a. Mollusca b. Porifera c. Echinodermata 2. Which of the following classes of Mollusca need a closed circulatory system? a. Cephalopoda b. Bivalvia c. Gastropoda d. Polyplacophora http://en.wikipedia.org/wiki/File:Tonicella-lineata.jpg

  20. Quiz Questions (Cont.) 3. Excretory functions are regulated by… a. Nephridia b. Tubular structures c. Both d. Neither 4. Land Snails reproduce… a. Through internal fertilization b. Through external fertilization c. Sexually d. Asexually 5. Why don't they serve escargots at a McDonald's restaurants? http://biology.unm.edu/ccouncil/Biology_203/Images/Protostomes/squid.jpg

  21. Answers 1. b 2. a 3. d 4. a 5. They only serve fast food 

  22. Thank You http://lair2000.net/Mermaids_Retreat/Research/kraken.jpg

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