Comparative Vertebrate Physiology

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Comparative Vertebrate Physiology

• Locomotion

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Energetics What does it cost?

• Smaller animals show higher rates of limb stride
  or wing motion, thus higher rate of muscle
  shortening in smaller animals, thus more energy

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Energetics

• Larger animals expend less energy moving a given
  distance

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How do animals move?

• Terrestrial locomotion

1. Walking and running Fewer points of contact
with substrate than number of limbs Maintain
equilibrium
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How do animals move?

• 1. Walking and running
• Gait
• Relative phase and duty factor
• Duty factor decreases with speed

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How do animals move?

• 2. Hopping and jumping
• Legs in phase
• Low duty factor when moving
• Low metabolic expenditure

Achilles tendon
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Factors effecting locomotion

• Inertia
• Momentum
• Drag determined by velocity, surface area and
  shape of an animal
• Larger animals experience less drag

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Drag

• Experienced by swimmers (high viscosity and
  density) and fliers (velocity), but not runners

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Aquatic energetics

• Swimming at the water surface is more expensive

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Aerial locomotion

• No buoyancy
• Low drag
• Lift enables high speed travel
• Gliding conserves energy

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Aerial locomotion

• Large animals generate more forward thrust
• Differing angles of wing beat among fliers

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Cost of transport

• Smaller animals havehigh cost of transportation
• At the same mass swimmingis most efficient
• Flying is more economicalthan running