Class Aves Flashcards

Bird Characteristics

• Birds are bipedal vertebrates, primarily adapted for flight.
• Most birds possess the ability to fly, characterized by specialized structures.
• Every bird has a bill, which varies in shape and size.
• Feathers are unique to birds (and some dinosaurs), serving critical functions.
• Feathers are filamentous, soft, flexible, and lightweight; essential for flight and temperature regulation.

Archaeopteryx

• Considered the oldest known bird fossil, dating back 150 million years.
• Demonstrates the evolutionary link between dinosaurs and birds, specifically theropods.
• Found in Germany and noted for limited flying capabilities.

Sinornis

• Represented a more advanced flyer compared to Archaeopteryx.
• Acts as a transitional fossil between modern birds and earlier avian species.

Dromaeosaur

• A 130 million-year-old specimen showcasing evidence of primitive feathers likely used for warmth.
• This small predator is related to Velociraptor, hinting at the evolutionary development of feathers.

Hesperonis

• Known as the "western bird," this genus comprises flightless aquatic birds from the Late Cretaceous period.

Avian Gas Exchange

• Unique respiratory cycle involving air flowing through the trachea and bronchi into posterior air sacs.
• First exhalation moves air from posterior air sacs to lungs, while second inhalation shifts air from lungs to anterior air sacs.
• Second exhalation expels air from anterior air sacs back through the trachea.

Preening

• Birds engage in grooming to maintain their feathers, enhancing condition and waterproofing.
• Involves the application of oil from specialized glands.

Types of Feathers

• Down feathers: provide insulation (e.g., in penguins).
• Contour feathers: shape and streamline the bird’s body.
• Flight feathers: specialized for primary and secondary flight functions.

Camber

• Refers to the wing shape, allowing air to flow faster over the top for efficient lift.

Three Axes of Flight

• Yaw: Dorsal/Ventral axis control.
• Pitch: Lateral axis control.
• Roll: Anterior/Posterior axis control for stability and maneuvering.

The Vee Formation

• Specific bird flight formation providing aerodynamic advantages to each bird in the group.
• Each bird reduces air turbulence for those behind, potentially saving up to 50% energy.

Superorder Palaeognathae

• Includes ratites, which are flightless birds known for their evolutionary traits.

Order Struthioniformes

• Comprised of ostriches, notable for being the largest flightless birds.

Order Rheiformes

• Consists of rheas, large, flightless birds found in South America.

Order Casuariiformes

• Contains cassowaries and emus, both incapable of flight.

Order Apterygiformes

• Features kiwis, small, flightless birds endemic to New Zealand.

Superorder Neognathae

• Encompasses all modern birds capable of flight.

Order Gaviiformes

• Commonly known as loons, specialized for aquatic life.

Order Pelecaniformes

• Includes diverse species such as pelicans, boobies, and frigatebirds.

Order Ciconiiformes

• Contains flamingos, noted for their striking coloration and social behavior.

Order Anseriformes

• Comprises ducks, known for sexual dimorphism in various species.

Order Falconiformes

• Encompasses birds of prey including vultures, hawks, and eagles, recognized for their hunting prowess.

Order Galliformes

• Features heavier, ground-dwelling birds such as turkeys.

Order Columbiformes

• Includes doves, pigeons, and sandgrouse, known for their robust navigation skills.

Raphus cucullatus

• Commonly known as the Dodo, an extinct flightless bird.

Order Strigiformes

• Represents owls, specialized for nocturnal hunting.

Order Caprimulgiformes

• Contains oilbirds, unique for their feeding habits and habitat.

Oilbirds

• The only known birds capable of echolocation, similar to bats.

Order Apodiformes

• Comprises hummingbirds, notable for their ability to fly backward.

Order Passeriformes

• The largest order of birds, includes 69 families of perching birds, with the American Robin as a prominent representative.