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How do these taxa relate?

How do these taxa relate?. How do these embryological features relate to Deuterostomes and Protostomes ?. Haeckel 1874, proposed phylum “Chordata” and 3 subphyla: ______________ ______________ ______________ (includes Hagfish). Basal Deuterostomes.

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How do these taxa relate?

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  1. How do these taxa relate?

  2. How do these embryological features relate to Deuterostomes and Protostomes?

  3. Haeckel 1874, proposed phylum “Chordata” and 3 subphyla: ______________ ______________ ______________ (includes Hagfish) Basal Deuterostomes

  4. Hypothesis that vertebrates and these “protochordates” share common ancestor provides impetus for study What features do these larvae share? How are they unique? Basal Deuterostomes

  5. _____________ (sea stars and allies) In fossil record from Cambrian to present ____ classes… today representatives of ___ Unique features: * * So why would they be considered “more closely related” than other marine invertebrates… say clam worms? Basal Deuterostomes http://www.palaeos.com/Invertebrates/Deuterostomia/Homalozoa/Images/Syringocrinus.gif

  6. _________________ (acorn worms) Bateson 1884, proposed Hemichordata as a subgroup of _____________ Basal Deuterostomes http://www.wildsingapore.com.sg/wildfilms/blog/050402cjd2070m3a.jpg http://coris.noaa.gov/glossary/hemichordate_186.jpg

  7. Hemichordata (acorn worms) 2-3 possibilities for taxonomic placement: * * * Basal Deuterostomes http://www.geol.umd.edu/~tholtz/G331/lectures/331grapt.html

  8. Features shared by echinoderms and hemichordates:*Similar ciliated larvae (________ and _______) * * Features linking to chordates: * * Basal Deuterostomes http://scaa.usask.ca/gallery/lacalli/images/tornaria3.jpg http://scaa.usask.ca/gallery/lacalli/images/cucumber5.jpg

  9. Filter-feeding marine organisms divided into 3 classes: *____________ (tunicates or “sea squirts”) * * Adults respire and feed using: * * __________sends food to _________, then __________ Urochordates http://www.youtube.com/watch?v=mecEpYS2Bgw

  10. Filter-feeding marine organisms divided into 3 classes: *__________________ Free-swimming plankton Large mucus tunic Urochordates http://homepage.mac.com/a.shiroza/pictures/planktons/bwttf/larvatian1p2_x50.jpg

  11. Filter-feeding marine organisms divided into 3 classes: *____________ (“salps”) Alternation of generations (free-living and colonial) No notochord… so why in phylum chordata? Urochordates http://chemistry.csudh.edu/faculty/jim/cantamar/salp.jpg http://www.youtube.com/watch?v=KRVdGam3G2U&NR=1

  12. * • 2 genera:*Branchiostoma *Asymmetron • * Cephalochordates http://comenius.susqu.edu/bi/202/Animals/DEUTEROSTOMES/cephalochordata/uwinnipeg-Lancelet.jpg

  13. Brief survey of systems: • Musculature and integument: • * • * • * • * • * • * • Advantages of thin skin? Cephalochordates

  14. Pharyngeal slits: • Exit to … • Filtered water leaves via … • …minimizes respiratory usefulness Cephalochordates

  15. “Skeletal” Notochord: • __________________more apropo • * • * • Notochord to rostrum adaptation for … • Other “skeletal” elements include: Cephalochordates

  16. Nervous system • * • *(38 vs. 10-18) • Spinal nerves with ___________ onlyconducting sensory (afferent) signals to spinal cord and brain • * Cephalochordates

  17. Digestive system • * • Buccal cirri coarse filter, monitor water • Vestibule bounded by oral hood and velum • * • * • Ciliated cells create … • Moves to midgut to mix with … • Intestinal cecum … Cephalochordates

  18. Circulatory system • * • * • * • Cecal vein assists by pumping to sinus Cephalochordates

  19. Excretory system • * • Cryptopodocytes (between protonephridia and podocytes) • * • * • Wastes leave via… Cephalochordates

  20. Reproductive system • * • Gonads (ovaries and testes)empty sex cells (eggs and sperm) into … Cephalochordates

  21. Compare - Contrast • No • No • No • 2 instead of 3 • 2 layered skin (1 cell thick) • No • Greatly reduced coelom • BUT many synapomorphies Cephalochordates

  22. Origin of craniates

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