bird origins 2 Flashcards
(20 cards)
what is microraptor gui notable for
4 winged dinosaur with feathered limbs
what was confuciusornis sanctus
beaked bird with sexual dimorphism, lacking teeth
what does sinornis show about bird evolution
mix of primitive (unfused bones) and advanced traits (keeled sternum)
what are icthyornis and hesperornis examples of
toothed seabirds from the late cretaceous
what group do all modern birds belong to
neornithes
what are ratites
flightless birds like ostriches, emus and kiwis
what are terror birds
extinct flightless carnivore birds
how is airflow managed in bird lungs
via unidirectional flow through parabronchi and air sacs
what is the benefit of air sacs
they allow efficient respiration and lightweight ventilation
how many air sacs do birds typically have
6-12
when did bird flight evolve
155 mya
which other vertebrates evolved powered flight
pterosaurs, bats and insects
what is Wing-Assisted Incline Running (WAIR)
a model of flight origin seen in young chukar partriges
what supports the arboreal theory of flight evolution
tree-dwelling dinosaurs glided before flapping flight
what is cursorial theory
ground running predators evolved flapping wings for propulsion
what does pouncing proavis hypothesis suggest
flight evolved from predatory ambush behaviour
what is flight stroke
coordinated wing motion producing lift and thrust
how does oxygen concentration affect flight evolution
high oxygen levels favoured larger bodies and flight ability
what do juvenile hoatzins demonstrate
clawed digits, reminiscent of Archaeopteryx
what structural changes support avian flight
fused bones, keeled sternum, lightweight skeleton
