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Comparative Vertebrate Physiology. Locomotion. 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. Energetics. Larger animals expend less energy moving a given distance.
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Comparative Vertebrate Physiology Locomotion
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
Energetics • Larger animals expend less energy moving a given distance
How do animals move? Terrestrial locomotion • 1. Walking and running • Fewer points of contact with substrate than number of limbs • Maintain equilibrium
How do animals move? • 1. Walking and running • Gait • Relative phase and duty factor • Duty factor decreases with speed
How do animals move? • 2. Hopping and jumping • Legs in phase • Low duty factor when moving • Low metabolic expenditure Achilles tendon
Factors effecting locomotion • Inertia • Momentum • Drag: determined by velocity, surface area and shape of an animal • Larger animals experience less drag
Drag • Experienced by swimmers (high viscosity and density) and fliers (velocity), but not runners
Aquatic energetics • Swimming at the water surface is more expensive
Aerial locomotion • No buoyancy • Low drag • Lift enables high speed travel • Gliding conserves energy
Aerial locomotion • Large animals generate more forward thrust • Differing angles of wing beat among fliers
Cost of transport • Smaller animals havehigh cost of transportation • At the same mass swimmingis most efficient • Flying is more economicalthan running