Fins limbs and vertebral column

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  1. Chondrichthye's fins

    - fins
    - composition
    most possess two dorsal fins-- one anterior (behind the head) and one posterior (in front of the tail)

    composed of basal cartilage
  2. Chondrichthye's fins

    - caudal fins
    Caudal fin in primitive chondrichthyes was externally symmetrical (despite asymmetrical internal skeleton)
  3. Chondrichthye's fins

    - pelvic and pectoral fins
    • show variation among the classes of organisms
    • - within derived chondrichthyes, fin muscles are present believed to help generate lift and movement
    • - they articulate with pectoral/ pelvic girdle via basal cartilages--> propterygium, mesopterygium, metapterygium
  4. Osteichthye's Fins

    -> ray-finned fish
    Fins are webs of skin supported by horny spines

    contain dorsal fin, fin rays, anal fin, ventral fin, and a caudal fin
  5. Lobe-finned fish
    • Only one species of lobe-finned fish still exists: Coelacanth
    • contain fleshy, lobed, paired fins
    • pelvic and pectoral fins resemble tetrapod limbs, which are believed to have evolved from these fins
  6. Amphibian limbs
    - all have four limbs except the legless caecilians and some salamanders

    - regenerative capabilities after injury or amputation of limbs

    - bones are fully ossified with no cartilage reminisces at maturity: shaft (diaphysis) of the bone takes up most of the length, ends of bones become epiphysis after ossifying-- allows for growth zones for cartilage around ossification centers between epiphysis and diaphysis
  7. Reptilian limbs

    - order crocodilia
    • differ from mammals in that the wrist has three rows of carpal bones
    • -- Proximal: radial, ulnar, intermedium, pisiform
    • -- Middle: three central carpals
    • -- Distal: 5 distal carpals
    • -- Plantigrade (all bones of manus on the ground)
  8. Reptilian limbs

    - order testudinata (turtles)
    • - appendicular skeleton includes flippers and hind limbs
    • - same long bones as mammals
    • - similar carpals and tarsals to mammals in flippers
  9. Reptilian limbs

    - order rhynchocephalia (tuatara)
    four limbs similar to crocodiles
  10. Reptilian limbs

    - order Squamata (snakes/ lizards)
    • lack paired limbs (snakes)
    • lizards similar to other orders
  11. Ave's wings
    adaptive modifications of manus

    • - birds: loss of digits and bones plus fusion of some bones
    • - bats: 5 digits, elongated metacarpals with phalanges to support the patagium
    • - pterosaurs-- 4th digit elongated to support patagium
  12. What is the patagium?
    membranous structure that aids an animal in gliding or flying
  13. Mammalian limbs:
    -- specific modifications


  14. Plantigrade
    monkeys, apes, humans

    • flat footed
    • all bones of manus on the ground
    • opposable thumbs--> saddle joint at base of thumb where it meets palm
  15. Digigrade
    rabbits, rodents

    • 1st digit is reduced or lost
    • manus and pes are elevated
  16. Ungiligrade (deer)
    • reduced number of digits
    • walk on tips of remaining digits
    • claws become hooves
  17. Osteichthye's vertebral column
    - ray finned fish
    pleurocentrem and intercentrum are fused

    resembles the vertebral body of most mammals
  18. Osteichthye's vertebral column
    - lobe finned fish
    • vertebral arch surrounds teh spinal cord
    • under arch is pleurocentrum, which protects the notochord
    • under pleurocentrum is intercentrum, also protects notochord
  19. Amphibian vertebral column
    • cylindrical piece of bone below the vertebral arch
    • no trace of separate elements present in early tetrapods
  20. Reptilian Vertebral Column
    • highly variable number of vertebrae
    • - several hundred can exist in a snake
    • contain haemal arches that attach below the base of the spine
    • often contain primitive intercentra
    • --> small crescent shaped bony elements lying between adjacent vertebrae
    • anterior surface of spinal cord has a concave socket.¬†
    • --> expanded convex face of the next vertebrae sits
  21. Birds
    • variable number of cervical vertebrae: allows for only true flexibility of bird
    • Thoracic vertebrae almostalways partly fused: provides brace for wings during flight
    • sacral are fused with lumbar vertebrae: can also contain some caudal and thoracic fused vertebrae; this fusion creates the synsacrum
  22. Mammalian vertebral colum
    cervical vertebrae (most superior): contain transverse foramina

    thoracic (inferior to cervical): contains costal fossa

    Lumbar (inferior to thoracic)

    Sacrum (inferior to lumbar)

    Typical vertebrae contain: superior/ inferior articulate fossa, spinous process, transverse process, lamina, pedicle, vertebral foramen, vertebral arch, and centrum
Card Set
Fins limbs and vertebral column
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