Class Aves; made adaptations for flight, which include: foreappendages modified as feathered wings, endothemic, high metabolism, flexible neck, fused posterior vertebrae, bones lightened by numerous airspace.Have a horny bill that lacks teeth.
Part of bird which provides attachment for flight muscles
Part of bird, also known as a wishbone, stores energy for recovery stroke
Part of bird, provides rigidity to trunk
Part of bird, allow firm grip even when asleep
Adaptations for flight
4-chambered heart, Endothermic, Forelimbs modified for flight
4- Chambered Heart
flight adaptation. More efficient oxygen delivery; Circulatory system has 2 separate circuits for oxygenated and deoxygenated blood.
Flight adaptation. Regulate body temperature above ambient temperature relying on metabolic heat.
Flight adaptatoin. Hand bones reduced and fused
Has visible wing claws as a chick. Wing claws fuse and become externally invisible.
Well-developed nervous system and sense organs
Excellent vision, Proportionately very large eyes, Large number of rods in retina of nocturnal birds, Large number of cones in retina of diurnal birds, Binocular vision, Most developed in owls.
Feathers are lightweight and flexible, yet impervious to air. May originally have evolved for insulation or display
Types of feathers
Pennaceous feathers and Plumulaceous feathers
Used for flight. Hooks (hamuli) allow feathers to spring back into shape even after a rough landing.
Primarily for insulation. Include down feathers
flapping flight. wings move forward and down
flapping flight. returns the wings to the position from which the next power stroke will commence
Power stroke; recovery stroke
Soaring on air currents (thermals), Saves energy, Allows for scavenging life style, Largest birds (vultures, condors) soar, Argentavis must have been a master soarer
In all probability, birds evolved from small theropod dinosaurs like Bambiraptor
Skeletal similarities b/een primitive birds and dinosaurs known for over a century. Protein (collagen) fragments in T. rex fossil appear to most closely match amino acid sequences found in collagen of present-day chickens.
Under the feathers, modern birds differ primarily in body size and shape of beaks and feet.
Modern Bird: nectar-feeder
Modern Bird: flesh tearer
Modern Bird: seed crusher
Modern Bird: plankton sifter
Are based off of adatations to different lifestyles and modes of locomotion. example: Swimming for a duck, climbing for a woodpecker.
Related to cranes, Different from any bird alive today, Dominant predators in S. America until rise of Central American land Bridge 3MYA, Titanis made it all the way to Florida and Texas
Amniotic egg with a hard shell, Most birds lack intromittent organ, Many birds are territorial during breeding season, Birds are both monogamous and polyginous
Bird Digestive System
Crop stores food, stomach contains Proventriculus and Gizzard.
secretes gastric juices
abrades and grinds food (birds have no teeth). Birds may swallow sand and pebbles to aid digestion
Group of eggs
Depends on both genetics and available resources. Some chicks practice sibling "murder" (ex.: Nazca booby)
can move about and find food. Usually covered with down
helpless at hatching, Huge appetites - keep parents busy, Must be brooded constantly because endothermy is not developed, Many birds have brood patch
Ex.: American robin