BIOL 2003 Lecture Notes - Lecture 22: Dinosaur, Theropoda, Archaeopteryx
Archosaurs – Dinosaurs and Early Birds
November 25-27, 2015
Crocodilia: withinin Archosaurs
o Closer to birds than lizards
o Parental care
o Four chambered heart
o Secondary palate
o Do not moult
o Dermal bony plates
o Modified legs, ankles (NOT a sprawled stance **secondary is advantageous in water because
ancestors were completely terrestrial)
o Entirely carnivorous
o Include:
▪ Dinosauria (including birds)
• Small when they originated (bipedal, 4 legs, unspecialized skull)
• Many were feathered, endothermic and ancestors to bird
• Completed 2 distinct lineages: pelivis
o Sauro,,, hebivores and carnivores; large body form;
o On,,, -
• Taradactyls – outgroup
• T-rex – very bizarre dinosaurs large size doesn’t suit lineages
• *No marine dinosaurs
• Dinosaur with spiked back is more related to mammals than dinosaurs
▪ Birds are dinosaurs – Aves
• Archaeopteryx is a bird rather than a dinosaur *first known
o May not actually be a bird
o Probably fles
o Probaby arboreal
o Small (crow size) carnivore
o Feathers were noted on the fossil
o Teeth, long bony tail, skeleton of a theropod dinosaur
o Not clear if actually flew, glided or ran
o Fossil:
▪ Unquestionable feather impressions
▪ Displays wings
▪ Insulation type feathers occurred first before blade light
feathers were present for flight
• Getting hard to tell birds from other dinosaurs
• Feathers:
o Derived from scales
o Beta-keratin
o Complex structure
o Blade like feathers decrease drag
o Several types:
▪ Insulating – downt
▪ Body contour – coverts flight fefathers
▪ Bristles
o Bird with all its feathers has its feather smoothed out in an
aerodynamic way
o Assymmetric blade is extremely strong and light with a hollow
shaft
o Creates almost a quilted pattern
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Document Summary
Insulation type feathers occurred first before blade light feathers were present for flight: getting hard to tell birds from other dinosaurs, feathers, derived from scales, beta-keratin, complex structure, blade like feathers decrease drag, several types: Inherited from dinosaurs: thin cylinder, internally reinforced with struts, maximum strength for minimum weights, human skeleton 12% bw; bird 5% bw, orignated in dinosaurs. Streamlining and laminar flow: essential for flight: turbulent flow: chaotic, high drag. **minimize upstroke force: wing shapes, elliptical wings forest birds, dynamic soaring wings, high-aspect ratio wings. *slower speed in complex environments: fit between branches, high camber (degree of curvature = greater lift, high drag. Sandpipers, hummingbirds, ducks etc: high speed, low drag, low camber, high wing loading (sweeps back; pointed tip; slender, highest lift: drag, high wing loading (long and narrow, fairly high speed, large turns, are not highly maneuverable.
