Lophotrochozoa (flatworms-octopus)

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  1. Phylum Platyhelminthes (flatworms)
    • acoelomate
    • -triploblastic but lack fluid filled body cavity
    • no special system for circulation or gas exchange
    • lack complete digestive system (have mouth and lumen (space) but no anus)
    • -parasitic lack mouth and guts
  2. what are the two types of flatworms?
    • free-living flatworms (class turbellaria)
    • tapeworms (class Cestoidea)
  3. Features of class Turbellaria (free living flatworms)
    • mostly marine and predatory
    • epidermis covered in cilia
    • pair of ventral nerve cords
    • pair of ganglia that act as brain near front
    • no anal opening, undigested food ejected through mouth
  4. Class Cestoidea (tapeworms)
    • endoparasitic (mostly in vertebrates, invertebrates act as intermediate host)
    • no digestive system, absorb nutrients 
    • scolex for holding onto host's gut
  5. What are proglottids?
    • behind tapeworms scolex (for attaching), long chain of units for reproduction
    • produced at base of scolex
    • mature proglottids at tail end and are filled with eggs
  6. Life cycle of a tapeworm
    • Need at least 2 hosts
    • eggs are ingested by the intermediate host where they grow into larvae go into muscles 
    • the final host consumes the intermediate hose where they develop into an adult
  7. What is a definitive host?
    the host where the parasite undergoes sexual reproduction
  8. Class Trematoda (phylum platyhelminthes)
    • complex life cycle (at least 2 hosts)
    • -adults are parasites in vertebrates, invertebrates act as an intermediate host 
    • "swimmers itch"
  9. Phylum Brachiopoda- lamp shells
    • true coelem
    • attach to substrate with a rubbery stalk
    • complete gut with anal opening 
    • use paired lophophores for suspension feeding
    • mainly in deep waters
  10. Phylum Ectoprocta "moss animals"
    • invertebrate
    • tough exoskeleton - important for building reefs
    • colonial (live close together)
  11. Phylum Annelida
    sea worms, earthworms and leeches
  12. Annelid characteristics
    • segmented, segments separated by septa
    • eucoelomate-body cavity is lined with mesodermally derived tissues
    • closed circulatory system
    • complete digestive system w/anus
  13. Class Polychaeta (sea worms)
    • mainly marine 
    • body segments have fleshy lobes (contain chaetae)
    • clearly differentiated head 
    • some sedentary, some errant (predatory)
    • free-spawning, fertilization occurs outside of parent
  14. Class Oligochaeta
    • less diverse than polychaetes
    • lack parapodia and well developed head
    • ingest substrate
  15. Oligochaeta reproduction
    • hermaphrodites
    • each worm acts as both male and female and implant sperm in each others seminal receptacle
    • clitellum secrete gelatinous cocoon, egg is deposited into cocoon, cocoon slides along worm and sperm is also deposited
    • fertilization is external
  16. Class Hirudinea (leeches)
    • mostly freshwater but a few marine and terrestrial
    • lack chaetae
    • have clitellum
    • secrete anticoagulent and anaesthetic
  17. Phylum Mollusca (snails, clams, squids)
    • mainly marine
    • characterized by calcareous shell (secreted by the mantle-thin layer) covering soft body
    • muscular ventral foot is used for movement 
    • organs are in visceral mass above foot
    • radula acts as mouth (convyer belt)
  18. Class Gastropoda (snails)
    • muscular contraction of large foot for movement
    • mainly marine
  19. How do Gastropoda (snails) breath?
    lungs rather than gills
  20. What do shelled snails undergo during development?
    torsion- visceral mass twists causing anal cavity to be over head
  21. What is a visceral mass?
    soft non-muscular region of molluscs containing organs
  22. What are Nudibranchs?
    • sea slugs
    • steal defenses of cnidarians (jellyfish etc)
  23. Characteristics of class Bivalvia (clams, oysters, and scallops)
    • mostly marine
    • feed by filtering water through gills
    • some are sessile
  24. Definition of sessile
    fixed in one place
  25. Class Cephalopoda (squids, cuttlefish, octopuses)-Phylum Molluscs
    • tentacles arranged around mouth
    • no external shell
    • all predatory
    • only mollusc with closed circulatory system
    • excellent vision
  26. Cephalopoda development
    • octopus exhibit maternal care
    • direct development
Card Set:
Lophotrochozoa (flatworms-octopus)
2014-03-30 23:38:55
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