Birds – Class AVES (Some classification schemes include Birds in the Class Reptilia) Several existing powerpoints were used to create this presentation – including the following sites: facstaff.uwa.edu/jmccall/BY321/Birds2.ppt dwww.occc.edu/biologylabs/.../Zoology
Bird Classification • 30 orders! • 10,000 species • Ex; Robins, owls, eagles, pelicans, hummingbirds, ducks, peacocks, ostriches, etc!!!!
Bird Characteristics • Inhabit most places of the globe • Endothermic “warm blooded” –lots of energy needed to keep body temp high – requires lots of food! • Diet is dependent on beak shape and habitat • 4 Chambers to Heart (2 Atria, 2 Ventricles) • Air sacs & lungs • Locomotion – Flying, Swimming, Running • Pectoral appendages = wings • Pelvic appendages = feet
Feathers = modified scales made of keratin • Sexual reproduction with internal fertilization Oviparous - Amniotic egg with calcium carbonate shell (In many species both parents care for young) • Uric Acid excretion (white “paste”) • Thin, hollow bones; some bones fused for extra strength • Scales on legs, toothless, horny beak • MANY Behavior Adaptations – Courtship rituals, Food gathering, Caring for young, Cooling themselves off (no sweat glands), GREAT problem solvers (especially Crows!)
Feathers(Modified Scales) Used in many ways • Flight • Regulation of body temperature (thermoregulation) • Protection of the body • Attraction of mates • Identification of species
Types of Feathers • Contour feathers (flight feathers) • Down feathers (soft & fluffy – cover body of nestlings, undercoat in adults) • Filoplume (pin feathers) • Bristles (nasal area)
Feather AnatomyOwl feathers are moreopen at the margins than otherbirds so they can fly silently tocatch their prey
Preening • A bird spends part of each day making minor repairs to tears in its feathers • Feathers are re-zipped • Preen gland at base of tail secretes oil • video Before After
Skeleton helps with flight Long neck, keeled and enlarged sternum (flight muscles attach to it) bones have air spaces (lighter!)
Skull • Most bones fused • Much lighter than reptile or mammal skull
Digestive System • Crop • Stores Food • Proventriculus • Secretes Enzymes • Gizzard • Grinds food • Cloaca • Eliminates Waste • Cloaca used in reproduction and excretion too!
Respiration -Air sacs and Lungs Birds have relatively small lungs plus air sacs. The air sacs permit a unidirectional flow of air through the lungs.. Therefore, in bird lungs, more oxygen is available to diffuse into the blood than in mammals Birds also have a vocal organ called a syrinx at the end of the trachea and attached to an air sac.
Circulation Very efficient! Birds, like mammals, have a 4-chambered heart (2 atria & 2 ventricles), with complete separation of oxygenated and de-oxygenated blood.
Excretion – • Uric acid is excreted as a white paste – conserves water • No bladder to store liquid waste
Reproduction • Male produces sperm in testes • Female only has one ovary • After mating, eggs are covered with Calcium Carbonate shell • Amniotic ggs are laid two days after mating • Eggs are incubated (chicken 21 days)
Chicks Altricial • No feathers • Cannot walk or see • Cannot feed themselves Precocial • Down feathers • Can walk and see • Can feed themselves
Bird Brains • Great vision and hearing • Poor sense of smell and taste • Complex problem solversvideo
Vision • Up to 8 times keener than human vision • 350 degree field of view • Each eye moves independently (increases field of view)
Benefits of Birds to Man • Eat insects, rodents and weeds • Spread seeds for flowers and trees • Food • Sport • Pets
Gee Whiz! • Fastest Animal on Earth! • Peregrine Falcon (->200 mph) video • Some birds migrate 25.000 miles! (Arctic Tern))
Evolution • Birds evolved from reptiles • Few fossils due to lack of preservation of feathers or thin, hollow bones • Several different fossil species have been studied – here are 3 your book mentions: • Sinosauropteryx, Caudipteryx, and Archaeopteryx
Archaeopteryx • Possible link between birds & reptiles • Large skull with reptile like teeth • Bones not hollow • Claws on forelimbs • Long tail • Strong legs & rounded wings for gliding • Feathers • Furculum - fused collarbone or wishbone