Aves Flashcards
what are the 4 pre adaptions in theropods that allowed flight to happen
- feathers
- pneumatized bones
- endothermy
- strong legs
what are features birds share with reptiles
diapsid
- single occipital condyle
- epidermal scales
- oviparious
- gizzard in digestive system
what are features both birds and theropods share?
- feathers
- synsacrum
- pnuematized bones
- fulcra
- static lungs with air sac
what are the derived features of birds
- feather covering majority of body
- edentulous
- sternal keel
- reduced reproductive system
what is the issue with bird phylogeny
it is hard to figure out which is the common ancestor because there is so much diversity so they decided to go with hard polytomy
how do the muscles and bones work to produce flight
downstroke (more powerful)
- the pectoralis major pulls down the humerus
upstroke
- the fulcra holds the energy of the downstroke and releases during the upstroke while the supracoracodeus contracts
how do the feathers aid in flight
- they can do the upstroke without creating down pressure
what are types of feathers and how do they help?
down
- thermal regulation
wing and tail
- asymmetrical and symmetrical for flight dynamics
contour
- creates an aerodynamic surface
describe at least 2 ways birds get their colour
- pigment absorbs all but one specific wavelength
understand the main reproductive adaption of birds
what were the skeletal changes from basal theropods to modern moderns and what were the roles of it