SLE204 Lecture Notes - Lecture 3: Metabolic Waste, Altricial, Amniote
9 Aug 2018
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Hypothesis: birds evolved from small theropod dinosaurs: flight: Insulation (down feathers for warmth; very soft) Display (cid:894)e. g. (cid:373)ales" (cid:271)right (cid:272)olour to attra(cid:272)t fe(cid:373)ale(cid:895) Hooks and barbs (cid:271)irds (cid:862)zip(cid:863) feathers together. Filoplume feathers newly developed feathers: adaptations for flight: Streamlined body = reduced resistance when moving through air. Pneumatic bones filled with air spaces reinforced with trabeculae. Light-weight bones (not found in diving birds, such as penguins -> their bones need to be heavier to dive) Loss and fusion of bones reduce weight; increase strength. > uncinate processes = (cid:862)hooks(cid:863) o(cid:374) ri(cid:271) (cid:272)age to rei(cid:374)for(cid:272)e it. > thoracic and caudal vertebrae fused no lateral movement stiff body for flight. > tail reduced to pygostyle -> few bones; support tail feathers. Loss of teeth = reduced mass formation of beak. Sternum with large keel = site of attachment for large flight muscles. Forelimbs modified as wings to generate lift: endothermy. Allow birds to live in all habitats regardless of climate: respiration:
