extant birds

Paleognathae

“Old jaw”

Joint between palatine and pterygoid doesn’t move

Primarily flightless

Neognathae

“New jaw”

Movable joint

Galloanserae

Chickens, ducks diverges from main avian evolution

Beta-keratin

Synapomorphy present in sauropods, main component of feathers

Skeletal adaptations to minimize weight and strengthen flight

-keeled sternum

-pneumatized bones

-fused bones in wings, legs, girdles

-strong hind legs for bipedalism

-Synacrum for rigidness and strength

Tarsometamarsus

Fusion of ankle bones with toes

Tibiotarsus

Tibia with ankle bones

Weight distribution

-hind limbs concentrated proximally

-moves mass towards the center of the body, enhances maneuverability

4 forces on a birds wings

-lift

-thrust

-drag

-gravity

Primary feathers

attached to the hand have

asymmetrical vanes and act as propellers to

generate thrust (helps maneuvering)

Secondary feathers

hers attached to the forearm form

for lift

The leading edge of the wing is supported by a

patagium and has a small winglet, the alula, that

increases lift at low speeds

High-speed wing

Migratory birds, flight feeding

Elliptical wing

high maneuverability in complex habitats

High aspect ratio wings

Dynamic soaring, seabirds

Slotted high lift

Static sparing using warm wind, raptors

Anisodactyly

: Perching birds have three toes

pointing forward and one back

Zygodaxtyly

Woodpeckers, owls, osprey and

parrots have two toes pointing forward and two

pointing back for grasping food or the substrate

Didactyly

Ostriches reduced toe number to two

for running, like some mammals

Bird tongue

Hyoids support the tongue

Cranial kinesis

enlarges the gape and

enhances the manipulatory ability of the

jaws.

Digestion and food processing

The crop can store food for later

processing, ferment vegetation, or

produce ‘milk’ for young

• The proventriculus or glandular

stomach performs chemical

digestion.

• The gizzard or muscular stomach is

used to grind food, often with small

stones