BIOL 329 Lecture Notes - Lecture 15: V Formation, Mesozoic, Bird
6 May 2018
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Lect 15
Neornithes:
Palaeognaths:
Tinamous: central and South American. Have keeled sternum and can fly. Colorful eggs.
Ratites: ostrich, rheas, emu, kiwi. Flightless – Aus, Africa, SA, Asia. Stem group had flight (these lost it).
Loons and grebes are not closely related. Great diversity in same monophyletic group. Pay attention to
grey phylogenetic tree (left of red line). Species: 500 in BC, 600 in Canada, 800 in NA _____
Basic biomechanics of flight: size constraints – living birds can reach 150 kg (ostrich). Extinct birds: 450
kg (elephantbird – Madagascar in 18th century) both flightless. Largest living flying bird is 20 kg: giant
condor w/ 3.2 m wingspan.
Reduction in the diversity of feather type compared to the Mesozoic.
Wing structure: Priaries attahed to hads. “eodaries – give ability to glide. Hummingbirds have
few, albatross have many. Albatrosses: increased speed by increased amplitude
Angle of attack (climb angle) can be increased by projections at the front of the wing as these produces
vortices that improve tighter flow to the upper wing surface at low flight speeds – alula (thumb).
Induced drag – drag producing vortices from lateral movement of air over wings. Longer wings reduce
the area of vortices relative to the lift area. Tapered wings reduce the area of vortices but at the
expense of lift area.
Aspect ratio = wingspan2 / area of wing
Shearwaters have high AR high lift, low drag. Grouse = low AR
Lift: Wing loading = mass of bird / area of wing
High WL: large mass, low wing area
Tail feathers (retrices) – primarily for breaking, steering and lift. Central pair are connected with
ligaments to pygostyle (fused last vertebra) and can be rotated – remaining pairs in retricial bulbs beside
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Document Summary
Pay attention to grey phylogenetic tree (left of red line). Species: 500 in bc, 600 in canada, 800 in na _____ Basic biomechanics of flight: size constraints living birds can reach 150 kg (ostrich). Extinct birds: 450 kg (elephantbird madagascar in 18th century) both flightless. Largest living flying bird is 20 kg: giant condor w/ 3. 2 m wingspan. Reduction in the diversity of feather type compared to the mesozoic. Angle of attack (climb angle) can be increased by projections at the front of the wing as these produces vortices that improve tighter flow to the upper wing surface at low flight speeds alula (thumb). Induced drag drag producing vortices from lateral movement of air over wings. Longer wings reduce the area of vortices relative to the lift area. Tapered wings reduce the area of vortices but at the expense of lift area. Aspect ratio = wingspan2 / area of wing. Shearwaters have high ar high lift, low drag.
