Question | Answer |
Name as many adaptions | 1. Thinner cortex and hollow bones 2. Internally, lightweight struts 3. Laterally flattened keel 4. Coracoid 5. Less joints 6. More cervical vertebrae |
Name as many adaptions cont. | 7. Longer neck 8. Lightweight beak 9. Quadrate bone 10. Craniofacial hinge 11. Fused bones |
How are thinner cortex / hollow bones adapted? | Lightweight |
How are internally, lightweight struts adapted? | Create honeycombed interior and reinforce bones |
How is the laterally flattened keel adapted? | Sternum extended this way > large surface area for attachment of major flight muscles |
How is the longer neck adapted? | Makes up for lack of flexibility in body, enable to turn head right around |
How is a lightweight beak adapted? | Covering mandible replacing teeth + reduces weight of skeleton (each species = characteristic beak for eating habits) |
How is the craniofacial hinge adapted? | Between upper beak / skull, increases mobility of beak during feeding |
Example of fused bones | e.g. tibiotarsus, tarsometatarsus |
How are the wings structured? | Bones of each forelimb reduced to humerus, separate radius and ulna, fused carpal and metacarpal bones and 3 digits |
Where are most wing muscles found and why? | Found on body / proximal end of wing + long tendons attached lower down the wing control movement (if flight muscles on wings extra weight impedes flapping flight) |
Where are most muscles on the leg? | Most muscles of leg = higher up on leg / body, controlling movement via long tendons |
What is the digital flexor tendon? | Runs in tunnel behind intertarsal joint and supplies each digit, responsible for perching reflex |
How many toes do most birds have? | Most have 3 toes, 1 pointing backwards and others forwards as adaption for perching / holding prey (parrots have 2 forward / behind though) |
How are ducks and rators feet adapted? | Shape reflects lifestyle e.g. duck = webbed for swimming, raptors = strong talons for catching / killing prey |
How are feathers structured? | Develop from epidermal cells, made from keratin creating a strong + lightweight covering Central shaft filled with blood capillaries during growth, maturation > hollow |
What is the vane of the feather? | Vane consists of barbs + interlocking barbules hooking together to form flattened, wind-resistant surface |
How are feathers kept clean and how? | ‘Zipping up’ barbules to apply secretions from preen gland at base of tail to keep feathers waterproof |
What are avian adaptions to the eyes? | Flexible lens, thicker retina, more cones / rods, two foveas and receptor cell density |
How are flexible lens adapted? | Change shape to focus near and far |
How are more cones / rods adapted? | Varies between species, diurnal (more cones) nocturnal (more rods) |
How are two foveas adapted? | Helps judge speed and distance, fovea is area of densely packed receptor cells which perceive sharper images |
How is receptor cell density adapted? | Allow birds to see in dim light |
What is a avian adaption for hearing? | Specialised feathers - most birds have this surrounding ear opening to minimise air turbulence |
What is a advian adaption to the central nervous sytesm? | Cerebellum - the center for motor control is well developed for flying + agility abilities |
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