Morphology and Locomotion Flashcards
What is a defining characteristic of the bones of many seabirds that is crucial to their ability to fly?
Bones are pneumatic (hollow) with internal struts that increase structural rigidity (they are also fused together)
Describe the key features of the thorax of seabirds that enable them to fly
- Furcula (wishbone): two collarbones fused together where ends meet
- Sternum (breastbone): flight bones are attached to a projection called the keel
What are the two major flight muscles in seabirds?
- Pectoralis
- Supracoracoideus
Both are attached to the sternum (keel)
What is the function of the pectoralis?
Lowers wings for downstroke (power stroke)
What is the function of the supracoracoideus?
Raises wings for the recovery stroke
What is the function of the alula?
Facilitates landing by allowing birds to create drag
What are the two muscle types in seabirds?
- Red-muscle fiber
- White muscle fiber
What is the function of red-muscle fiber?
Endurance oriented aerobic activity (ex: walking, sustained flight)
What is the function of white-muscle fiber?
Explosive anerobic movements (ex: predator evasion short explosive flight)
Define aerodynamics
Demands imposed by getting off the ground and staying in the air
What are the two key features of aerodynamics?
- Lift
- Drag
Describe lift
An upward force that gets birds off the ground and keeps them in the air
What produces lift?
The movement of air around and past an airfoil
What is an airfoil?
Any shape that produces lift and drag (for birds it is a wing)
Describe the mechanism required to produce lift in birds?
- Air flowing over the top of the wing must reach the back of the wing at the same time as the air flowing underneath the wing
- Wings are curved so… the top of the wing is longer relative the bottom of the wing
- Air flowing over the top of the wing must go faster than air flowing underneath the wing
- The result of this difference in speed is lower pressure above the wing and higher pressure below the wing