%20%20Definition,%20types.webp "Aerial adaptations (Volant adaptations) : Definition, types")
The adaptations for flight are called Volant adaptations. The flight may be active or passive.
1. Adaptations for active flight -
The active flight is character of bats, birds, insects and some other mammals like flying squirrel.
Flight adaptations of a bird as followers.
2. Adaptations for passive flight (gliding)
This type of flight is performed by a number of arboreal animals like the flying fish (Exocoetus), flying dragon (Draco), flying frog (Rhacophorus) and by some mammals. Their adaptations are as follows-
Flight adaptations of a bird as followers.
- Shapes of the body - The shape of the body, which boat or spindle like itself offer almost no resistance and hence it is easily propelled through air.
- Wings - In birds and bats forelimbs are modified into wings. The wings of birds have flight musceles which controls the movement of wings.
- Feathers - The birds have an exoskeleton of feathers, which are several types. The flight feathers of a wing form a broad surface for supporting the bird in air. Feathers also provide insulations, that prevents loss of heat ans maintains a constant temperature of the body.
- Short tail - The short tail of bird bears a series of tail feathers arranged in a fan like manner and serves as rudder in steering and as a counter balance in perching.
- Flight Muscles and keeled sternum - In birds specific flight muscles are well developed. The sternum bears a keel of for attachment of pectoral muscles whose tendens are inserted on the head of the humerus. When pectoralis major contracts the wings is lowered so that the body of bird is propelled through the air while the contraction of pectorals minor raises the wing up. These are accessory depressor and tensor muscles which keep the wing fully stretched during flight.
- Pneumatic bones - The bones are pneumatic which make the body light the fusion of bones make the endoseskelaton compact and rigid. Which are perfectly suitable for flight.
- Air sacs and respiration - The thin walled membranous air sacs provides lightness and buoyancy to the body. They also serves reservoirs of air and aid in the regulation of the body temperature.
- Brain and sense organs - Sight and optic lobes are well developed. Birds have large cerebellum which maintain equilibrium and coordination. Eyes bear sclerotic plates that resist variable air pressures during flight.
- Physiological adaptation - All other bodily systems of a bird are also adapted for flight. The rectum is reduced as faucal is less that keep the body light. Heart functions very efficiently to bring about a rapid circulation and perfect aeration of blood that are necessary for high metabolism. There is no urinary bladder then excretions are solid or semisolid which keep the body light. Presence of single ovary of the left side of the female bird that reduce the total weight of the body.
2. Adaptations for passive flight (gliding)
This type of flight is performed by a number of arboreal animals like the flying fish (Exocoetus), flying dragon (Draco), flying frog (Rhacophorus) and by some mammals. Their adaptations are as follows-
- Development of patagia - Patagium is fold of skin between the fore and hind limbs. In Draco it extends on either side of trunk and supported by 5to 7 pairs of long ribs while flying Gecko patagium extend along the side of body. tail and limbs and between toes.
- Enlargement and high insertion pectoral fins - In Exocoetus pectoral fins are very large they are used as parachutes which helps the fish to make great leaps out of water therefore fish actually sails through the air.
- Webbed feet - In Rhacophrous (flying frog) the feet are webbed which make long leaps. The digits in adhesive pads which help in sticking to the smooth surface.
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