Morphology and Locomotion Flashcards

1
Q

What is a defining characteristic of the bones of many seabirds that is crucial to their ability to fly?

A

Bones are pneumatic (hollow) with internal struts that increase structural rigidity (they are also fused together)

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2
Q

Describe the key features of the thorax of seabirds that enable them to fly

A
  1. Furcula (wishbone): two collarbones fused together where ends meet
  2. Sternum (breastbone): flight bones are attached to a projection called the keel
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3
Q

What are the two major flight muscles in seabirds?

A
  1. Pectoralis
  2. Supracoracoideus
    Both are attached to the sternum (keel)
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4
Q

What is the function of the pectoralis?

A

Lowers wings for downstroke (power stroke)

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5
Q

What is the function of the supracoracoideus?

A

Raises wings for the recovery stroke

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6
Q

What is the function of the alula?

A

Facilitates landing by allowing birds to create drag

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7
Q

What are the two muscle types in seabirds?

A
  1. Red-muscle fiber
  2. White muscle fiber
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8
Q

What is the function of red-muscle fiber?

A

Endurance oriented aerobic activity (ex: walking, sustained flight)

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9
Q

What is the function of white-muscle fiber?

A

Explosive anerobic movements (ex: predator evasion short explosive flight)

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10
Q

Define aerodynamics

A

Demands imposed by getting off the ground and staying in the air

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11
Q

What are the two key features of aerodynamics?

A
  1. Lift
  2. Drag
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12
Q

Describe lift

A

An upward force that gets birds off the ground and keeps them in the air

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13
Q

What produces lift?

A

The movement of air around and past an airfoil

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14
Q

What is an airfoil?

A

Any shape that produces lift and drag (for birds it is a wing)

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15
Q

Describe the mechanism required to produce lift in birds?

A
  1. 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
  2. Wings are curved so… the top of the wing is longer relative the bottom of the wing
  3. Air flowing over the top of the wing must go faster than air flowing underneath the wing
  4. The result of this difference in speed is lower pressure above the wing and higher pressure below the wing
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16
Q

How do feathers function as airfoils?

A
  • They are asymmetrical
  • The outer vane is narrower than the inner vane
  • The result is a curved feather
17
Q

Why is it important that bird feathers have a curved shape?

A

Similar to the shape of the bird wing the curvature is necessary for creating the pressure difference required to generate lift (higher pressure underneath the feather lower pressure on the top). The pressure gradient is the result of the air at the top of the feather flowing faster than the air on the bottom.

18
Q

What is the importance of drag?

A

Reduces lift by slowing the air moving over the wing

19
Q

Define turbulence

A

Disruption of air flowing over the wing

20
Q

Define thrust

A

Foward force generated during flapping flight (utilized to gain lift)

21
Q

Wing loading

A

The ratio of weight to wing area (how much body weight is weighing down the wings)

22
Q

How do you calculate wing loading?

A

Body mass/Surface area (kg/m^2)

23
Q

Aspect ratio

A

Ratio of a wing’s length to it’s width

24
Q

Describe wing shape if you have a high aspect ratio

A

Long and skinny (narrow)

25
Q

Describe wing shape if you have a low aspect ratio

A

Wings have similar length and width

26
Q

Why is aspect ratio imporatant?

A

Higher aspect ratios reduce drag (facilitate gliding)

27
Q

Describe the wing loading and aspect ratio of a bird that has a high wingbeat frequency

A
  • High wing loading
  • Low aspect ratio
  • Both
28
Q

Describe the wing loading and aspect ratio of a bird that has a low wingbeat frequency

A
  • Low wing loading
  • High aspect ratio
  • Both
29
Q

Describe gliding flight

A
  • Common in birds with high aspect ratio
  • Utilize weight to overcome air resistance when moving forward
  • Only large birds glide regularly
30
Q

Describe soaring flight

A
  • Utilizing atmospheric processes to gain altitude
  • Common in birds with low wing loading and high aspect ratio
31
Q

Describe flapping flight

A
  • Up and down movement of the wings generates thrust
  • Downward stroke (“power stroke”): generates the most thrust (wing forms a solid airfoil)
  • Upward stroke: Tips of primaries separate allowing passage of air through slots (reduces friction)
  • Proximal portion of the wig moves less and provides the most lift
  • Distal portion of the wing generates thrust
32
Q

If a bird is a better diver than flyer, is their wing loading low or high?

A

High

33
Q

If a bird is a better flyer than diver, is their wing loading low or high?

A

Low

34
Q

Why is underwater locomotion energetically costly?

A

Water is more dense and viscous than air

35
Q

What are the 3 types of water locomotion?

A
  1. Swimming on the surface
  2. Wing propulsion
  3. Foot propulsion