Paleontology unit 1

• Where to Vertebrates originate from?

  They originate from the phylum chordata:

  -notochord

  -Pharyngeal slits

  -hollow, dorsal nerve cord

  -post anal tail

  -endostyle or thyroid
• What are the Vertebrate characteristics

  -Bones

  -specialized kidney tubules; marine origins

  -Brain case and vertebral column

  -Blood circulation patterns

  -Gut outgrowths- liver and pancreas

  -Neural crest cells

  -Cephalization

  -Neural Photoreceptors

  -Bilateral cleavage in embryos

  -secondarily formed mouths

  -Early important new charcaters
• What are the shared derived characteristics from the Chordates

  -Dorsal, hollow nerve cord

  -Notochord
• Draw a chordate
• Define Amphibians

  Adapted to survive at land-water interface
• Reptiles

  can remain on land, including reproductive changes; no water immersion requirements
• Agnatha 


  Jawless fishes
• Chondrichthyes 


  Cartilaginous fishes
• Osteichthyes are bony fish
• Aves are birds
• What are the different geological time periods?

  Eon


  Hadean 4600 mya, Archean 3800 mya Proterozoic 2500 mya, Phanerozoic 542 mya
• Phytosaur Cranium 


  Upper Triassic crocodilian like reptile, w many large, pointed teeth.
• Chracaradon megalodon have teeth up to 6 feet long and are ancestors to white sharks
• What is stratigraphy 


  the study of sediment layers; strata
• How does the shape of the animals affect water resistance

  Hard Edged disks= great resistance

  anything with round surface=Create turbulence, water is sucked back to its body and creates more resistance

  Laminar flow= more efficient; less turbulence, easier to swim
• Ordovician and silurian are some of the early fossils dating 443-417 mya in the Devonian era. Eariler specimen are heavily armored (bony fish), later species had loose armor and cartilaginous (sharks)
• What is the Devonian era

  The era of fishes
• What are paraphyletic? what groups are within it?

  Bony fishes

  -Osteichtyans

  -Sarcopterygians
• What are bones made of

  Mineral and protein components, hexagonal apatite crystals plus, collagen fibers, living tissue, remodeled throughout life, osteocytes control bone formation.
• What are agnathan?


  Animals without jaws;Paraohyletic(unknown origin)

  From Devonian to present time
• Exoskeleton vs endoskeleton

  Exo- external;armor plates

  Endo- provides internal body support
• what are tail and Side affect Swimming

  Tail provides main thrust

  Side- side movements may have impaired lateral stability
• Arandapsid are 470 million year old jawless fish about 20 cm long. Found in Australia.
• Astraspis one of the oldest vertebrate known from N. America. Described from fragmentary plates of bone.
• Sacabambilla- A fish from bolivia that its head is covered with bony plates. body is covered by long chevrons, allowing flexibility. Although head is not very flexible
• sacabambaspis- 450 million years ago located in Bolivia. Under 30 cm long. Late Ordovician.
• Drepanaspis- early Devonian 4000 mya dorsoventrally flattened, lived on sea floor and no paired fins.
• osteostracans have massive head shields (heavy armor). There are 300 species. Ordovician to late silurian/Devonian early. Paired fins covered with small scales. Various head shapes.
• What are Hemicyclaspis 


  Group known as Cephalaspids.

  Typical Osteostracan

  Lives in fresh water

  400 mya

  20 cm long

  paired pectoral fins

  Dorsal fins

  Early devonian England
• Pituraspida 


  related to osteostraci + Galeaspida. Heavy bony head shields. Unusual, large opening below eyes.

  General features:

  -Teeth

  -Jaws

  -ear region and horizontal sensory canal

  -gill arches internal to gills

  -paired fins and external skeleto

  -Stomach

  -constriction of notochord, solid vertebrate in several groups

  -dorsal fin

  -Anal fin

  -Vertebral column differentiated into abdominal, caudal and tail region