Birds

dinosaurs

what group of species were birds closely related to?

2nd most abundant vertebrate group

how abundant are birds?

feathers

unique bird characteristic

wings

how are bird forelimbs modified?

walking, swimming, perching

bird hindlimb function

lay eggs

how do all birds reproduce

Keratinized beaks with no teeth

all birds have this mouth structure

Respiratory, digestive, circulatory, nervous

what systems must be adapted to meet the high demands of flight?

they are hollow

how do bird bones adapt for flight

archaeopteryx

-fossil that linked birds to therapod dinosaurs

-showed some characteristics of a bird and some of a reptile

long s shaped neck, furcula (wish bone) consisting of fused clavicles, feathers on short hindlimbs

Similarities that allowed for grouping of birds and dinosaurs

thermoregulation and courtship displays

early functions of feathers

exaptation

how did feathers evolve (since they changed their function over time)

it is keeled

what is unique about the sternum of flying birds?

contour feather

-vaned feathers that streamline the bird body

-most common bird feather

quill, barbs

Hollow ________ emerges from skin follicle and continues as a shaft or rachis; bears numerous ___________ in parallel fashion

barbules

extend and spread laterally from each side of a barb

filoplume feathers

hairlike, degenerate feathers with a weak shaft and tuft of short barbs at the tip with no known function

down feathers

short tufts without rachi (shaft), found under contour feathers and function as insulation

powder-down feathers

found in herons and their relatives in which they disintegrate and release a talc-like powder to waterproof feathers and give off the metallic luster

light but sturdy

Requirements of a bird skeleton

yes

can a bird’s feathers outweigh it’s skeleton?

fused into 1 kinetic piece

modern bird skull

all but the cervical

what vertebrae are fused in birds?

pygostyle, synsacrum

caudal vertebrae fuse to form this structure, then the remaining vertebrae fuse and form the _______

increases stiffness in framework

why are bird vertebrae and ribs fused?

furcula

can store energy as it flexes during wing beats

pectoralis muscle

attatched to the keel, depresses the wing in flight when contracted

superacoracoideus muscle

attatched to the keel to raise the wing in flight

carnivorous

nutrition of early birds

eurypahgous or stenophagous

nutrition of current birds

euryphagous

species eat a wide variety of items and can switch to whatever is seasonally abundant (omnivores)

stenophagous

species are specialists and focus on a few selected foods; \n can be vulnerable if their food source is reduced or jeopardized

beaks

adapted for different feeding habits of birds

crop

-stores food at lower end of esophagus

-produces lipid and protein rich fluids used to feed hatchlings when parents regurgitate food

gizzard

muscular stomach that contains grit that grinds larger food

proventriculus

Birds of prey such as owls form a pellet of indigestible material in the __________ and eject it through the mouth

proventriculus and gizzard

2 parts of bird stomach

paired ceca

at the junction of intestine and colon to serve as fermentation chambers for herbivorous bird

cloaca

receives products from digestive, urinary, and reproductive systems

larger

bird eyes are _____ relative to body size than mammal eyes

eyes are less spherical and muscular so they can’t move independently

why do birds need to turn their whole head to scan an area

rods, cones

birds have _______ for dim light and _______ for color

trees-down and ground-up

2 main hypothesis for bird flight

birds that feed during flight or have long migrations

where are high-speed wings found?

hard to keep bird airborne at low speeds

challenges of high-speed wings

less maneuverable

challenges with dynamic soaring wings

dynamic soaring wing

-found in albatrosses, gannets, and other oceanic soaring birds which have long, narrow wings. \n - high-aspect ratio wings lack wing slots and allow high speed, high lift

high-lift wings

- have an aspect ratio intermediate between elliptical wings and high-aspect ratio wings. \n •-Vultures, hawks, eagles, owls, and other birds of prey that \n carry heavy loads have wings with slotting, alulas, and \n pronounced camber that produces high lift at slow speeds

concavity on a wing, helps with bearing weight

what is camber

testes

what enlarges during reproduction in birds?

cloacas are put together

how does gamete exchange occur in birds

left ovary and oviduct develop

what happens in female birds for reproduction