Vert. Zoo. unit 6

birds and crocodiles

when did birds appear

cretaceous period 125 million yrs ago, toothed like shorebirds, modern skeleton

cursorial flight

running and jumping like geese, from chasing insects

arboreal flight

climbing trees and gliding down

croc integument

armored bodies, long snouts, powerful tails, scales are separate and can be replaced, have dorsal armor from heavy plates of bone in dermis known as osteoderms

contour feathers

large firm vanes with downy base, arise from feather follicles in tracks (pterylae) patches between tracts are apteria

types of wing feathers

primaries- wrist to wingtip, secondaries- elbow to wrist, tertiary- shoulder to elbow

rectrices

tail feathers, often used for quills

semiplumes

loosely webbed contour feathers, no firm vane, fluffy, insulate and increase buoyancy

down feathers

smaller and fluffier, barbs absent or dont lock, natal down of hatchlings, random distribution

powder-down feathers

tips disintegrate into talc to protect from moisture, most common in parrots and herons

bristles

shaft but no vanes, around mouth nostrils and eyes, sense, trap insects, and sensory

filoplumes

hair like, no vanes, decorative or sensory, in peacocks

erector muscles

arrectores plumarum, used to ruffle/puff feathers for display and insulation

molting

most have single annual molt, post nuptial/ pre migration. some do partial molt prenuptial to aquire breeding plumage

prorphyrins

red, green, and brown bird feather pigment

owl feather

have comb like fringe on leading edge of wing to reduce turbulence and soft fringe on trailing edge

New Guinea Pitohu

has toxic feathers from beetle diet, gets sterodial alkaloid (the same as poison dart frogs)

uropygial glands

what waterfowl use to coat their feathers with oil to repel water

croc skeleton

complete secondary pallate, thecodont, legs can be sprawled or semi erect, webbed toes for axial movement when in water

bird skeleton

incomplete secondary pallate, light but strong bones, skull is thin and fused, marrow reabsorption, neck is highly flexible with up to 20 vertebrae, beak is elongated premaxillary and dentary bones

pygostyle

tail bones, 4-7 fused vertebrae

carinate bones

have keeled sternum to support large pectoral muscles needed for flight, in penguins and flying birds

ratite bones

in flightless birds, no keeled sternum, ostriches and emus

croc muscles

open mouth by lifting head, weak with small muscles, closing mouth using huge extremely powerful muscles

red muscles fibers

smaller in diameter, for continued strenuous activity, greater blood supply with more mitochondria and O2, dark meat

white muscles fibers

short periods of intense activity, white meat

avian pectorals

largest paired muscle of all the tetrapods, can be up to 25% of total bird body weight

hind limb muscles

highly specialized for perching, have flexor tendons that lock toes around branch when legs are bent

cardiovascular

oval and nucleated RBC’s, 4 chambered heart, size of heart and heart rate vary inversely with size

countercurrent heat exchange

capillaries are close enough to veins that warm blood from the body goin down warms up cold blood from the extremities moving up, ectothermic, homeothermic

homeostasis

to hot- pant and dilate vessels, too cold- ruffle feathers, shiver

rete-mirable

where to junction between capillaries and vessels accurs

croc respiration

nostrils with valves to close, and internal nares at rear of oral cavity closed by tongue, liver acts as piston (diaphragm) on lungs

bird respiratory system

highly modified lungs with 7-12 air sacs, trachea looped/coiled to resonate sound, lungs are smaller than mammals but air sacs make them 2x larger, may occupy up to 80% of body mass, 2 cycles for the in air to leave

syrinx

where bird vocalizations originate

croc digestive system

short, theco. homo. and polyphyodont, non protrusible tongue

bird digestive system

no teeth (egg tooth is scale), few taste buds, some tongues protrusible, most (ex- aquatic) have well developed salivary glands, oral glands for mucous especially cave swifts, crop stores food, gizzard crushes it with rocks

crop milk

fatty secretion mixed with regurgitated seeds that doves and flamingos feed their young, stimulated by prolactin

croc nervous system

cerebral hemisphere enlarged, no pineal organ, optic, cerebellum and auditory lobes well developed

birds nervous system

olfactory reduced (ex- carrion and sea birds), cerebral hemisphere better than reptiles (except crocs), optic and cerebellum advanced, cerebellum less in flightless birds (coordination)

projections neurons

neurons that can be replaced with age, for song learning and production

eyes

birds are the most visually dependent verts. retinas have rods for night and cones for color in the day, eyes have flat back and limited mobility, lens can change focuses fast, can see UV and polarized light

fovea

areas of retina with keenest vision, in a deep pit, may have two

ears

crocs have tympanic membrane, birds lack pinnae, used for balance and equilibrium along with hunting, owls use the facial disc like a radar, cave swiftlets echolocate, some can hear frequencies below humans (infrasound)

urogenital

birds- only ostriches have a bladder, only the left oviduct functions (weight) males testes enlarge in mating season, swans ducks and ostriches have a penis

bloom

protective shell of bacteria around egg

clutches

songbirds 1-3 clutches/year, 3-6 eggs/clutch, california condor one egg every 2 years, based on photoperiod, Ca for egg comes from bone

eggs laid per season

determinate- fixed

indeterminate- will lay to replace lost egg

eggs and water

eggs lose 15 % of water, to little evaporation can drown embryo and to much can dry it out

sex role reversal

males are courted and take care of the young, in spotted sandpipers and red phalaropes

croc natal care

guard nest, tear it apart when babies hatch, carry young to water

altricial baby birds

naked with sealed eyes, useless, lower success rate and higher predation rate

precocial baby birds

fluffy and eyes open, need less care

flight use

escape, travel, finding food and mates

flight mechanics

air flower over top of wing has less drag and is faster generating 66% of the lift, 33% comes from air floing under the wing

elliptical wing

low aspect ratio, maneuver in forests, passerines woodpeckers and the like

high speed wing

2:1 or 3:1 aspect ration, long migration or feeding in the air, wings sweep back and taper, swallow gulls hummers and swifts

soaring wings

high aspect ratio 6:1, long narrow and pointy, albatross and gannet

highlift wings

high lift at low speed, broad, soar on air currents, predators that carry heavy loads

migration

set in stone, emerged in ice age, summer breeding grounds to winter feeding grounds, optimal areas, instinctive triggered by ecological changes

migration routes

some major routes, stagger times to not overuse resources, can go by weather or instinct, artic tern goes longest distance

migration navigation

land marks, innate timing and sense of direction, magnetic field

integument

variable, lightweight, waterproof, can have epidermal scales (rat and beaver tails), dermal plates (armadillo), melanin, hair glands, baleen, horns, nails, keratinized stratified (layered) squamous epithelium