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  1. The rise to dominance of the paleozoic fauna occured during
    the Ordovician radiation
  2. Phylum Echinodermata include
    • Crinoids (lilies)
    • Echinoids (urchins)
    • Holothurians (sea cucumbers)
    • Asteroids (star fish)
  3. characteristics of Phylum Echinodermata
    • skin made of calcite plates (ossicles)
    • pentameral symmetry (imposed over bilateralP
    • water vascular system
    • no head
  4. Phylum Chordata include
    sea squirts, lancelets, and vertebrates
  5. defining characteristic of Phylum Chordata
    • notochord: stiff structure of tightly woven muscle fiber that runs the axis of the body
    • likely evolved for swimming (locomotion)
  6. The notochord was advantageous to primitive fish because
    it provided support for muscle attachment, yet was flexible enough to allow undulatory motion (developed into the discs between vertebrae in humans and others)
  7. subphyla of Chordates
    • Urochordates (tunicates: sea squirts)
    • Cephalochordates (amphioxus: lancelets)
    • Vertebrates
  8. life of Urochordates
    • vagrant larval stage with notochord and nerve chord
    • sessile adult looses notochord and nerve chord
  9. The closest living invertebrates relative of the vertebrates are
    cephalochordates (same phylum)
  10. characteristics of Cephalochordates
    • have a notochord and nerve chord throughout life
    • no vertebrae or protective brain case
  11. characteristics of Vertebrates
    • ossified backbone
    • nerve cord (spinal cord or DHNC)
    • "gill" slits (i.e. pharyngeal gills/pouches)
    • head w/ paired sensory organssegmented muscles
    • more derived groups have: paired appendages and jaws
  12. Pikaia
    early chordate of the middle cambrian
  13. conondont animal
    early chordate of the cambrian-triassic per.very useful for biostratigraphy
  14. early chordates of the lower Cambrian
    Chengjiang: Haikouella, Cathamyrus, Haikoueichthyes
  15. Haikoueichthyes
    • the first vertebrate (first fish)
    • jawless (Agnathan)
    • 515 Mil years ago (lower Cambrian)
  16. Agnathan
    • jawless vertebrates
    • most primitive (least derived) of the Vertebrates
    • extinct: Ostracoderms, Heteostracans, Osteostracans
    • extant: hagfish, lampreys
  17. Ostracoderm
    • Agnathan
    • "plated skin"
    • Ordovician
    • no paired fins
    • not very hydrodynamic
    • head plates = phosphatic plates
  18. Heterostracan
    • Agnathan
    • Silurian-Devonian
    • first abundant fish
    • eyes on side of head: likely bottom feeders
    • hydrodynamic head shields
  19. Osteostracan
    • Agnathan
    • Late Silurian Devonian
    • paired fins (better maneuverability, controls pitch-yaw-roll)
    • mouth under flat head shield = bottom feeders
  20. Hagfish
    • most primitive living Agnathan
    • no cartilage, bone, or scales
    • lives in deep waters
    • secretes sticky slime as defense
  21. Lamprey
    • Agnathan
    • secondarily lost bony armor = cartilage skeleton
    • mouth full of sharp teeth
    • parasitic: sucks blood from host
  22. Gnathostomes
    • jawed vertebrates
    • evolution of jawed fish = decline of agnathans
  23. Where do jaws come from?
    • modified gill arches
    • initially evolved for wider gape to help with respiration
  24. Acanthodians
    • lower Silurian
    • 1st jawed fish
    • potentially contained true teeth
  25. Placoderms
    • major Devonian predators
    • massive head shields with cartilaginous bodies (probably couldn't move well)
    • no true teeth
    • dominant for about 50 million years then fizzled out
  26. Chondrichthyes
    • evolved in Devonian
    • abundant from Devonian to present
    • Cartilaginous skeletons
    • very successful group
    • diverse throughout
  27. Osteichthyes
    • bony fish
    • - actinoterygians (ray fins)
    • - sarcopterygians (lobe fins)
  28. ray finned fish
    • Osteichthyes
    • dominant from Devonian to present
    • skeleton of light bone
    • very agile
    • fins full of many long ray-like bones
  29. lobe-finned fish
    • fins with a few thick bones
    • Devonian to recent
    • not as agile as ray fins
    • Some have lungs and gulp air to breathe
    • ancestor to the tetrapods
    • ex. lung fish (Dipnois)
  30. Coelacanth
    • gnathostome (jawed vertebrates)
    • thought to be extinct
    • deep water predators
    • no lungs
  31. Osteolepiforms
    ancestral taxa to the tetrapods
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