Zoology Lecture 13

  1. What is paculiar about platyhelminths yolk and and ova
    that yolk is not depositied in the ova but instead ova and seperate yolk cells are packaged as capsules
  2. What is this sort of egg like pattern known as
    Ectolecithal eggs –Neöphora
  3. ________ and some other turbellarian Orders have the more conventional pattern of ova that include yolk.
  4. What is the more traditional yolk pattern known as
    Entolecithaleggs –Archöphora
  5. Spiral cleavage with determinate development.
    –1d progeny form ____________
    –2d ________________
    –4d the
    • anterior epidermis & NS.
    • muscle & mesenchyme of pharynx
    • mesentoblast forms gastrodermis& most mesenchyme.
  6. Development in the Neöphora, Planaria
  7. Does the Development in the Neöphora, Planaria have typical spiral cleavage if not why not?
    change in the egg yold relationship has led to different patterns then conventional spiral cleavage
  8. As cleavage starts, two populations of yolk cells what are they
    • Large, spherical lipid rich yolk cells
    • Motile, RNA-rich fusiformyolk cells.
  9. As cleave continues, the motile yolk cells ________ around the _______ and forms a syncytium.
    • aggregate
    • embryo
  10. After formation of the yolk syncytium, continuing cleavage leads to two sets of _________.
  11. The first population forms a cryptic larva that is mostly pharynx-gut and feeds on the yolk syncytium. just saing
  12. Later the second population becomes the ___________ which replace the tissues of the cryptic larva and form the _______ of the juvenile worm.
    • embryonic cells
    • body
  13. Parasitic classes just saying
  14. The parasitic classes have __________, and protonephridial, ________ and reproductive systems like turbellarians.
    • mesenchyme
    • nervous
  15. They have _________ organs of one type or other.
  16. In addition to being Neöphora, the parasitic classes at some stage in life loose the _________and develop a new outer covering
    –_________making them the Neodermata.
    • ciliated epithelium
    • tegument
  17. Tegument 1 ust saying
  18. What are the two regions of the tegument
    • 1. outer anucleate synctium
    • 2. inner nucleate region (high metabolic turnover)
  19. Where does the tegument originate from? what is it fromed from? hwat is this inital layer called at embryogeniss?
    the tegument (from mesodermal origin) replaces the epidermis (from epidermis during embryogenisis)
  20. Are all teguments the same?
    No. Surface topography varies from group to group
  21. What does a tegument consist of roughly
    a glycocaly layer overtop of a gelatenous (?) layer with a basment membrane which was created and connected toa number of open cell bodies with nuclei inside each one
  22. What types of interspecies relationships would you expect to see with flaties
    commensalism, mutualism and definitly parasitism
  23. what -odes would you expect to see in parasitic relationships specifically
    • All cestodes
    • monogeneans
    • trematodes
  24. Define Primary or definitive host
    Host in which the adult parasite is found
  25. Define Secondary or intermediate host
    host in which the juvenile or larval stages are found
  26. Define vector
    Vector - acts as an agent that actively transmits the parasite to another host.
  27. What are three fairly obvious ecological barriers to the establishment and the growth of the parasite
    • Time
    • Space
    • behavioural events
  28. Physiological barriers –pH –pCO2, –pO2 –temperature –osmotic concentration –nutrient availability –failure to excystor hatch in gut
  29. Biotic barriers –primary host defences (macrophages) –secondary host defences (immunity) –interspecificinteractions (host/parasite, parasite/parasite) –intraspecific(crowding) –host/parasite signals that affect parasite maturation
  30. What is the "rule" for parasite feeding or nutrietion
    Trans-Tegumentary feeding
  31. Just because trans-tegumentrary is possible does that mean no parasites have a gut?
    no. some parasites do have a gut
  32. What methods does tapeworms use in order to obtain nutrition
    diffusion, active transport, pinocytosis and phagocytosis
  33. What is an irony of a parasite taking nutrution from host?
    the fact that the parasite will dump waste products back into the host for the host to deal with
  34. are reproductive systems between the three parasitic classes similar or dissimilar? do they resemble any other class?
    they are similar. They resemble the triclads
  35. What type of reprodction (dimporphism etc) are the parasites? what do they produce as a final product
    They are all hermaphrodidic and they produce an ectolecithal egg
  36. What does monogenean infect
  37. What do indirect life cycles allow for when it comes to larvae
    indirect life cycles allow for larval amplification
  38. fig 8.2 showing the hosts including human as the definitive host as well as a fish and a snail that flukes must use. a sheep can also be a host
  39. more life cycles to view
Card Set
Zoology Lecture 13
Zoology Lecture 13