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A Ecl 365

Bird Worksheet

  1. This is one of the best recorded evolutionary transitions in fossil records (for vertebrates).
  2. Class Aves, birds
  1. True / False Birds form a monophyletic group.
  2. True
  1. Name 4 characteristics of birds.
  2. Feathers – light body covering
  3. Four-chambered heart
  4. Strictly oviparous
  5. One ear ossicle – columella
  6. Endothermic homeotherms
  7. Flow-through respiratory system
  8. Bill
  9. Hollow bones, fusion of bones
  10. Excrete uric acid
  1. How many chambers are there in the avian heart?
  2. 4
  1. True / False All homeotherms are endothermic.
  2. False
  1. Name 3 adaptations for flight, as discussed in class.
  2. Birds have only one ovary, gonads reduced in off-season
  3. Bones are hollow
  4. Loss of teeth
  5. Rapid digestion
  1. Name two characteristics of Dromeosaurs that became more bird-like through time.
  2. Flexible and rotating wrist structure (greater prey manipulation)
  3. Shift in shoulder joint (allows greater range of motion)
  4. Transition of feathers from small filaments to larger vaned feathers
  5. Additional avian characteristics also seen: keeled sternum, arms capable of flapping
  6. Clavicles form furcula= fused clavical = wishbone (wishbone)
  7. Derived group of theropods with birdlike characteristics
  8. Characteristics become more birdlike through time
  1. Name one Dromeosaur.
  2. Caudipteryx, Sinosauropteryx, Protoarchaeopteryx
  1. What find, first a feather impression in a German quarry in 1861 and then a full skeleton in 1862, revealed the link between dinosaurs and birds?
  2. Archaeopteryx
  1. Name three characteristics of Archaeopteryx.
  2. Fossil dates to Jurassic(150 MYA)
  3. First true bird
  4. Many intermediate in its features between theropods and birds
  5. Feathers
  6. Had clawed forelimbs (the Hoatzin of A. Amer. Has vestigial wing claw at birth)
  7. Teeth in sockets
  8. Long bony tail
  9. Sternum unkeeled
  10. Has furcula = fused clavical = wishbone
  1. Fossils from the Cretaceous displayed additional birdlike characteristics, name 3.
  2. Toothless beak
  3. Collarbone strongly connected to sternum
  4. Reduced 1st and enlarged 2nd hand digits
  5. Fused foot bones
  6. Keeled sternum
  1. Feathers derived from ______
  2. Reptilian scales
  1. What are possible reasons feathers developed?
  2. Flight
  3. Thermoregulation
  4. Protection from solar radiation
  1. Describe the Arboreal Hypothesis
  2. Theory (trees down hypothesis)
  3. Hypothesis of jumping à gliding à flying hypothesis
  4. Ancestors were tree climbing dinosaurs
  5. Leaped between trees
  6. Structures that could increase distance and break falls (feathers, wings) would be selected for over time
  1. Compare and contrast the Cursorial Hypothesis, Cursorial Hypothesis II, Cursorial Hypothesis III.
  2. Cursorial Theory (ground-up hypothesis)
  3. Hypothesis of runningà glidingà flapping
  4. Ancestors were bipedal runners and predators
  5. Wings used to increase lift and lighten load for running
  6. Wings then flapped for additional forward propulsion

f.  This hypothesis insufficient biomechanically, because flapping would NOT increase speed (more traction required for this)

  1. Cursorial Theory II (ground-up hypothesis)
  2. Refined hypothesis of runningà glidingà flapping
  3. Incipient wings used as snares to trap prey or bat them out of air
  4. Wing evolved for flapping to subdue larger prey
  5. Flight developed from ground up where arms were used to capture food. This took weight off feet -> ran faster ->gliding -> flapping flight
  1. Cursorial Hypothesis III (ground/water-up hypothesis)
  2. Refined hypothesis of runningà glidingà flapping
  3. Ran across water (like basalisk)
  4. Wings used to increase lift and lighten load for running
  5. Wings then flapped for additional forward propulsion
  1. Birds are ____ in diversity, behind ______
  2. 2nd, Osteichthyes
  1. True / False All birds are capable of flight.
  2. False (All but 100)
  1. ______are the most basal group of birds.
  2. Rattites (Struthioniformes)
  1. True / False Bony fishes are a monophyletic group.
  2. True
Hypothesis / Type / Ancestors / Development / Comments
Arboreal / Trees-down / Tree climbing dinosaurs / Leapt between trees, structures that increased distance, break falls / Most Supported
Cursorial I / Ground-up / Predators, bipedal runners / Wings flapped for speed, lighten load / Insufficient, would need greater traction for speed
Cursorial II / Ground-up / Predators, bipedal runners / Flapped/grabbed at prey with arms, took weight from feet
Cursorial III / Ground/water-up / Ran across water / Increase lift and lighten load; forward propulsion