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Invertebrate Zoology

Lecture Notes 

Rotifera - Entoprocta

 

Notes:  This is an outline of my class notes - details and visuals will be given in class!

Read: Chapter 15 in Hickman, Roberts & Larson.

  1. Phylum Rotifera
    1. L. rota - wheel + fera, - bearing
    2. Row-tiff' e-ra
    3. Figures 15-2 to 15-4 pp. 306-308
    4. 1,800 species
    5. Bilateral symmetry
    6. To 3mm long
    7. 3 embryonic germ layers: endoderm, mesoderm, ectoderm
    8. Organ level of organization - 10,000 cells
    9. Extracellular digestion in complete gastrovascular system
    10. pseudocoel
    11. Excretory system (protonephridia)
    12. Simple respiration by diffusion
    13. Anterior ganglia and two longitudinal nerve cords
    14. Sense organs, some with eyespots
    15. Wheel of cilia, trophi
    16. No skeletal system
    17. Reproduction usually sexual
      1. Sexual forms dioecious
      2. Some species show parthenogenesis
        1. At certain times of year haploid eggs are produced
        2. Haploid eggs yield males
        3. Diploid eggs at other times of year - produce females
    18. Marine, freshwater, some terrestrial, some parasitic
      1. Many interstitial

     

  2. Phylum Gastrotricha
    1. Gr. gaster - stomach + trichos, - hair
    2. Gas-tro-tri' ka
    3. Figures 15-5 to 15-6 p. 309
    4. 400 species
    5. To 0.5mm long
    6. Hairs on body
    7. Reproduction usually sexual
      1. Sexual forms monecious
    8. Marine, freshwater, some terrestrial
      1. Many interstitial

     

  3. Phylum Kinorhyncha
    1. Gr. kinein - to move + rhynchos, - beak
    2. Kin' o-ring' ka
    3. Figure 15-7 p. 310
    4. 100 species
    5. To 1mm long
    6. More advanced brain
    7. Reproduction usually sexual
      1. Sexual forms dioecious
    8. Marine
  4. Phylum Loricifera
    1. L. lorica - corselet + Gr. phora, - bearing
    2. Lore i siph' a ra
    3. Figure 15-8 p. 311
    4. Described in 1983
    5. 40 species
    6. To 0.25mm long
    7. Body surrounded by lorica
    8. Reproduction usually sexual
      1. Sexual forms dioecious
    9. Marine, interstitial
  5. Phylum Priapulida
    1. Gr. priapos - phallus + Gr. ida, - plural formation
    2. Pri' a pyu' li-da
    3. Figure 15-9 p. 311
    4. 15 species
    5. To 15 cm long
    6. Reproduction usually sexual
      1. Sexual forms dioecious
    7. Marine, burrowing
  6. Phylum Nematoda
    1. Gr. nematos - thread
    2. Nem-a-to' da
    3. Figures 15-10 to 15-17 pp. 313-316
    4. 12,000 species (up to 500,00?)
      1. 1 species from under felt beer coasters in a few towns in eastern Europe
    5. hydrostatic skeleton
    6. thick, non-cellular cuticle
    7. Bilateral symmetry
    8. To 8m long
    9. Extracellular digestion in complete gastrovascular system
    10. pseudocoel
    11. Excretory system (no protonephridia)
    12. Simple respiration by diffusion
      1. Many species anaerobes
    13. Ring of nerve tissue and two longitudinal nerve cords (dorsal and ventral)
    14. Reproduction usually sexual
      1. Sexual forms dioecious
    15. Marine, freshwater, terrestrial, many parasitic (plants and animals)
      1. Many interstitial
    16. Parasitic forms:
      1. Most have single host, some require secondary host
      2. Some filarial forms spread by biting insects, particularly in tropics
      3. Ascaris feeds on intestinal contents
      4. Hookworms feed on blood in intestine
      5. Trichina worms encyst in muscle
      6. Pinworms feed on intestinal contents
      7. Filarial worms feed on material in lymph system
  7. Phylum Nematomorpha
    1. Gr. nema - thread + Gr. morphe, - form
    2. Nem' a-tomor' fa
    3. Figure 15-18 p. 317
    4. 250 species
    5. To 70cm long
    6. Juveniles parasitic in hemocoel of arthropods, including insects and crabs
    7. Circulatory, excretory, respiratory systems lacking
    8. Reproduction sexual
      1. Sexual forms dioecious
    9. Parasitic, aquatic
      1. Juveniles of terrestrial insects cause the insect to seek out water.
  8. Phylum Acanthocephala
    1. Gr. akantha - spine + Gr. kephale, - head
    2. A-kan' tho-sef' a-la
    3. Figure 15-19, 15-20 p. 315
    4. 500 species
    5. To 1m long
    6. Reproduction sexual
      1. Sexual forms dioecious
    7. Endoparasitic in vertebrate intestines
      1. Require secondary host for larvae
  9. Phylum Entoprocta
    1. Gr. entos - within + Gr. proktos, - anus
    2. En' to-prok' ta
    3. Figure 15-21 p. 319
    4. 150 species
    5. To 5mm long
    6. Ciliated filter feeders
      1. U-shaped gut
    7. Reproduction usually sexual
      1. Sexual forms monecious, dioecious, some protandric
    8. Marine, benthic; 1 freshwater genus

 

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