Introduction

Question 1

Physical Characteristics

Answer 1

• Hindlimbs adapted to walking
• Horny beak, no teeth
• Single middle ear bone
• Syrinx-voice box
• Truncated caudal vertebrae
• No urinary bladder
• Aorta branches to right
• Females-only left ovary developed
• Leg scales
• Lay eggs with hard calcareous shells
• Feather

Question 2

First bird fossil and describe

Answer 2

Archaeopteryx lithographica

• Reptile like skeleton
• Had feathers
• Still retained teeth

Question 3

Early Amniotes

Answer 3

Birds are derived from the diapsid lineage of early amniotes

Question 4

What are birds most closely related to?

Answer 4

Therapod Dinosaur group

Question 5

Bird & Reptile similarities

Answer 5

• Single occipital condyle
• Single middle ear bone
• Lower jaw (5-6 separate bones)
• Excrete uric acid as metabolic waste
• Yolked egg

Question 6

Skeletal adaptations to flight

Answer 6

• braincase expanded and fused
• Hand bones fused
• Pelvic bone fused
• Caudal vertebrae reduced and fused
• Large sternum (has keel)

Question 7

Pneumatic bones

Answer 7

• thin walled
• extremely lightweight and rigid
• strengthened by internal struts

Question 8

Flight muscles

Answer 8

Keel - Increased surface area
Pectoralis - Downstroke
Supracoracoideus - Upstroke

Question 9

Ground up theory. What are the benefits

Answer 9

• Cursorial origin of flight (run and glide)
• Feathers aided in leaping, maneuvering

Benefits:

• Escape predators
• Capture prey
• lighten load (running)

Question 10

Arboreal theory

Answer 10

Theory that states flight originated from the trees

Question 11

Flightlessness?

Answer 11

• Evolved independently in various taxa
• Often in areas of reduced terrestrial predation
• those who survived on larger landmasses could run fast enough to escape