bird origins 1 Flashcards
(20 cards)
are birds considered reptiles
yes, they are feathered theropod dinosaurs
what group of dinosaurs did bird evolve from
theropods, specifically Coelurosauria
what is the significance of Archaeopteryx
oldest known bird, transitional between reptiles and modern birds
what are uncinate processes
rib extensions that stiffen the thorax, seen in birds and dromaeosaurs
what kind of vertebrae do birds have
10-26 cervical vertebrae for neck flexibility
what material is feathers made from
beat-keratin
what are the functions of the feathers
flight, insulation, camouflage, sexual display
what type of eggs do birds lay
shelled, amniotic
how many middle ear bones do birds have
one called the columella
what is the lower jaw of birds made of
multiple bones
what dinosaur had filamentous proto feathers
sinosauropteryx prima
what did causipteryx show about feather function
likely used for display not flight
what are gastroliths
stomach stones aiding in digestion, seen in some dinosaurs and birds
why is tail reduction important in bird evolution
improves flight balance, modern birds have a pygostyle
what skeletal feature aids in powered flight
a large keeled sternum
what is the funtion of the supracoracoideous muscle
raises the wing during upstroke
what evidence links birds to velociraptors
shared skeletal traits like semi-lunate carpal bones and feathers
what is the significance of maniraptoran dinosaurs
direct ancestors of birds
what are remiges and rectrices
wing and tail flight feathers
are birds a monophyletic group
yes, supported by morphological and genetic evidence
