Unit 16

Question 1

Ornithischia

Answer 1

“Bird-hipped“
- pubis oriented caudally (pointing backwards)
- convergent evolution and not shared ancestry with birds
• Thick skulls, horns and other ornamentations
• Weapons and/or intraspecific combat
• Parental care
• Vocal communication

Question 2

Saurischia

Answer 2

“Lizard-hipped“
- Pubis oriented forward
- Some have reversed pubis like Ornithischians/birds (Maniroptera)
Two lineages: Sauropodomorpha (Greek saur=reptile, pod=foot, morph=form) and Theropods

Question 3

Sauropodomorpha

Answer 3

• Largest terrestrial vertebrates that ever existed
• Herbivorous
• Primarily quadrupedal, elephant-like gait
• Long neck (feeding? or sexual competition)
• Cheeks to process food
• Herd behaviour
• All extinct at Cretaceous-Tertiary extinction

Question 4

Theropods

Answer 4

Tyrannosaurs

Coelurosaurs

Question 5

Shared characteristics of theropods and birds

Answer 5

• Elongate, mobile S-shaped neck
• Tridactyl foot (3 toes forward; 1 backward)
• Digitigrade posture
• Intertarsal ankle joint
• Hollow, pneumatic bones
• Feather precursors or true feathers
• Reduced genome size

Question 6

Early bird

Answer 6

Archaeopteryx (Dromaeosaur)
• dates to the Jurassic, ~150 mya
• Gliding
• Solid reptilian bones
• Asymmetrical vaned feathers
• Wing feathers (primaries and secondaries) + tail feathers
• Large furcula and rectangular sternum (strong flight muscles?)
• Not a direct link between Dromaeosaurs and birds (separate lineage?)

Question 7

Evolution of bird

Answer 7

Thecodonts — ornithodira — dinosauria — saurischia
-ornithischia -Sauropods
—theropods — Coelurosaurs (dromaeisaurs) — BIRD

Question 8

Characteristics of flight

Answer 8

Camber
Wing loading
Aspect ratio

Question 9

Birds vs pterosauria

Answer 9

No furcula
Wings supported by 4th digit
Patagium wing surface

Question 10

Convergent bird and pterosauria traits

Answer 10

Large brain case
Ossified keeled sternum
Hollow skeleton
Reduced fibula
Loss of teeth and tail
Fused vertebrae

Question 11

Shared characteristics of birds and Coelurosaurs

Answer 11

Furcula
Fused honey sternum
Egg brooding and sleeping postures
Flexi-wrists
More flexible shoulder joint

Question 12

Symmetric feather vane

Answer 12

Social display

Insulation (down feathers)

Question 13

Asymmetric feather vane

Answer 13

Pennaceous feather

Flight