Aerial Locomotion - notes PDF

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Comparative form and functioning in animals

Aerial Locomotion Air behaves like a fluid – when air is moved, other particles move with it which means drag and lift still apply Air has a lower density than water and there is a constant effect of gravity  Aerofoil is the same things as a hydrofoil – air on the top of the wing moves faster than the air underneath, creating a circular motion of air around the wing, resulting in a vortex creating lift.

Invertebrates Insects wings have a rigid outer structure and a flexible membrane Forward powdered flight - Movement of wings is similar to the movement of fins in lift-powered swimming; they can move their wings in a S shape - Wing is rotated in the upstroke (and positioned at an angle) to avoid downward-lift. Hovering - Types of hovering rely on the wind, they are roughly flying into the wind at the same speed it is blowing back, to keep a still position  Difference between hovering and forward flight is the angle of the body, relative to the ground Wing movement: 1) Creates lift / angles wing horizontally 2) Stalling movement 3) Rotates wing fully 4) Rotates wing fully 5) Stalling movement 6) Creates lift Insect flight muscles The muscles that power flight are attached to the thorax and the wings - the change in the thorax is what forces the wings up and down – this maximise the power of their wings There are muscles that are attached to the wing and these control the orientation of them.

Vertebrates Wings are similar to insects in terms of shape, by integration with the endoskeleton allows the wings to be more flexible They can hover, use forward flight and soar(ing) Hovering Humming birds: wings rotate in a figure of 8  They push their wings forward, pushing the air down, they push their wings back at an angle to reduce drag - kestrels can bend their wings during the backstroke to reduce drag even more

Comparative form and functioning in animals Forward powered flight Their bodies move in an S shape –on the upstroke they change the shape of their wing to reduce lift – bend their wings up and down, keeping their head forward. Vertebrate wing muscles  The muscles are attached to the edge of the wing, giving a weak force advantage meaning they need big muscles: but a good distance advantage.   The breast bone is modified to allow the attachment of large muscles.

Gliding (no flapping of the wings) Lift (from wings), drag (air resistance) and weight (promoted by gravity) must all be balanced  Larger birds glide faster – difference in wing shape also contribute to speed  Gliding angle is changed by moving the wings: higher angles = higher speeds – backwards increases the angle.  Gliding further means increasing the speed at the expense of faster height loss Soaring Occurs when there is a vertical component to the wind and the wind is somewhat going upwards –  many prey animals take advantage of these up-ward winds to hover without flapping: scan for prey -

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Slope soaring: When there is a wave created the wind is blown up and over it to bird fly up the wave and over, pushed by the wind – gain height from the wind Thermal soaring: takes advantage of warm convection currents: which are rays on land which create currents of air Eagles and vultures use it Need very flexible wings Not commonly used as the environmental conditions of most places aren’t right for it....