Lab 8. Aves Flashcards
Features shared between reptiles and aves
- Scales on legs
- Single occipital condyle
- Lower jaw = 5 fused bones
- Gizzard
- Metanephric kidney
- Nucleated erythrocytes
- single middle ear bone
- amniotic egg and egg tooth
- parental care
Integument Feathers general
- lift and steering during flight
- insulation, endothermic maintenance of high metabolic rate
- waterproofing
- courtship, camouflage, species recognition
3 types of feathers
- Pennaceous
- Plumaceous
- Filoplumaceous
Filoplumaceous
lack barbs/barbules along most of length
sensory role
Plumeaceous
“down”
rudimentary shaft with barbs and barbules that don’t interlock
insulation
Pennaceous
prominent rachis, barbs branch out.
overlapping barbules branch out from barbs, joined by hamuli (hooks) that keep them firm and smooth
2 types of pennaceous
- Flight feathers
2. Contour feathers
Flight feathers
asymmetrical
leading edge shorter than lagging edge
bend without twisting
flight
Contour feathers
symmetrical, line body and cover base of wings
waterproofing, insulation, streamlining
Remiges
flight feathers
Retrices
tail feathers
Moulting
Feathers moult. Sometimes birds can’t fly during moulting, some only moult some flight feathers at a time so they can still fly
4 key skeletal modifications
- Lightweight skeleton
- Strong and rigid skeleton
- increased bone surface area
- Flexible neck
Lightweight skeleton
large internal spaces strengthened by strutting
reduced number of skull bones and lightweight bill
Increased bone surface area
accomodate flight muscle attachement (like keel)
Flexible neck
allow range of movement because forelimbs can’t be used for manipulation
Food acquisition and digestion
Eat lots due to high metabolic rate and endothermy
Bills modified to exploit habits and food sources
Sensory abilities
Complex sensory and motor system due to flight
Complex learning capabilities and social behaviour
Reproduction
Internal fertilization, cloacal contact transfers sperm
Oviparous
Intricate mating behaviours
High parental care investment
Gas exchange
- Consume more O2 than any other vertebrate so very efficient
- No “dead air”
- Unidirectional respiratory system
- Air sacs (blind, thin-walled destensible extensions of lungs in all major parts of body, no direct role in gas exchange)
- 2 cycles
Respiration cycles
cycle 1
- inhalation: o2 air enters nares, through trachea, bronchi, into abdominal air sacs
- exhalation: air goes to parabronchi, o2 goes into blood stream
Cycle 2
- inhalation: moves to thoracic air sacs
- exhalation: expelled from body
They overlap
uropygial gland
produces oil for preening to make waterproof feathers
Nitrogenous waste
uric acid
4 types of beaks
- generalist
- raptorial
- chiseling
- flattened
Generalist
cracking seeds
raptorial
hooked for tearing flesh
chiseling
long for digging out insects
flattened
filtering and fishing
Slow phase muscle
red (turkey vulture)
Fast phase muscle
white (ruffle grouse)
Order of pigeons
Columbidae
Are pigeons perching birds
no
cloaca
releases excretory and genital products
Olfaction?
most birds don’t rely on it but pigeons use it for homing maybe
keel
extension of sternum, large surface for pectoral muscles in flying birds
furcula
wishbone
fusion of 2 clavicles
strengthens thoracic skeleton to withstand flight
pygostyle
triangular plate made of caudal vertebrae. supports tail feathers to steer
tarsometatarsus
fusion of tarsal and metatarsal bones used to accelerate for takeoff
crop function
- temporarily store food
- crop milk
crop more developed in insect or grain birds
grain cause they can hold lots many grains at once and then leave to digest in safer place. Hard to get big amounts of food as predator
In crop what do you see
undigested food
what is ventriculus
“gizzard” helps mechanically break down food with stones
