Birds Flashcards
What is a bird
Feathers Wings Warm blooded Beak (no teeth) Lays eggs, makes nests Hollow bones Unidirectional airflow in lungs
Archaeopteryx
- toothed beak (reptilian character)
- wing claw (reptilian)
- airfoil wing with contour feathers (avian character)
- long tail with many vertebrae (reptilian)
feathers older than birds
- feathers evolved before birds
- probs for display rather than flight
bird-dinosaur link
- n.o. of digits?
- I-II-III like dinosaurs
paedomorphy
adults retain juvenile features
Modern bird skeleton
tail greatly reduced
vertebrae fused
teeth lost
hollow bones
Lungs + air sacs
- Birds have relatively small lungs but also have air sacs
- Flow of air is unidirectional (more efficient as avoids mixing old and new air)
- inhalation: air sacs fill
- exhalation: air sacs empty; lungs fill
How many repiratory cycles to move air through system?
2
archosaurs
unidirectional airflow
dinosaurs
hollow bones, air sacs, feathers
birds
powered flight
flight
- escape predators
- new food sources
- migrate when seasons change/environment deteriorates
adaptations to flight
a) wing
b) bone structure
c) feather structure (shaft, barb, barbule, hook)
wing shape
- high aspect ratio (broad and narrow)
- slow gliding, soaring e.g. albatross
wing shape
- high aspect ratio (broad and narrow angled)
- high speed e.g. falcon
wing shape
- low aspect ratio (broad and wide) with deep slots at tips
- large inland birds, e.g. vultures
wing shape
- low aspect ratio, elliptical wings
- tight maneuvering, rapid take off
loss of flight
penguin, dodo, ostrich etc
precocial
- born with eyes open
- feathers
- can leave nest
- can feed themselves
- Female invests energy in eggs
- Less energy in parental care
- Typically adults have smaller brains (chicks may have relatively large brains)
altricial
- born helpless
- nude
- eyes often closed
- parents must feed
- Less energy in eggs
- More energy in parental care
- Adults can provide high quality food
- Adults tend to be larger brained
Palaeognathes
- old jaws
- upper beak fixed to skull
Neognathes
- new jaws
- upper beak can move upwards
Galliformes
game birds
Anseriformes
water fowl (ducks)
Dromornithidae (mihirung)
-extinct flightless Anseriformes from australia
bird brains
-similar sized brains to equivalent-sized mammals
metatools -Crows
using one tool to get another tool
convergent evolution is a…
process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches
