Comparative Vertebrate Physiology Locomotion. Energetics: What does it cost? Smaller animals show...
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Transcript of Comparative Vertebrate Physiology Locomotion. Energetics: What does it cost? Smaller animals show...
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 locomotion1. Walking and running
Fewer points of contact with substrate than number of limbsMaintain 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