Ch. 27 Class: Aves - Birds

Comprehensive vocabulary flashcards covering the biological characteristics, anatomy, physiology, and mating systems of Class Aves based on lecture slides.

Class Aves

A class of birds comprising approximately $11,400$ species with a cosmopolitan distribution.

Archaeopteryx

A transitional form between reptiles and birds that lived $147-155$ million years ago, possessing toothed beaks, wing claws, and airfoil wings with contour feathers.

Beta keratin

A strong, fibrous protein that makes up bird feathers.

Molting

The periodic process by which birds shed and replace their feathers.

Uncinate processes

Extensions on the ribs that serve to prevent over-compression during flight and respiration.

Syrinx

The vocal organ of birds, containing tympaniform membranes.

Carina

The keeled sternum that provides an attachment site for large flight muscles.

Pygostyle

The fused terminal vertebrae of the tail.

Pneumatization

The evolutionary adaptation of hollowing bones and adding internal struts to lighten the skeleton for flight.

Furcula

The fused clavicle bone, often referred to as the wishbone.

Pectoralis

The primary muscle responsible for the downward power stroke in flight.

Supracoracoideus

The muscle responsible for the recovery stroke in flight, configured in a rope and pulley arrangement.

Crop

An enlargement of the esophagus used for food storage.

Proventriculus

The part of the bird's stomach that secretes digestive enzymes.

Gizzard

The muscular part of the digestive tract used for grinding food.

Parabronchi

The tube-like lungs of a bird where gas exchange occurs through a continuous flow of air.

Air sacs

Structures that facilitate a $2$-cycle respiratory process, ensuring fresh air flows through the lungs during both inspiration and expiration.

Uric acid

The primary nitrogenous waste product excreted by birds to conserve water.

Salt glands

Specialized glands that assist the kidneys in regulating salt, particularly in marine birds.

Pecten

A highly vascularized structure in the bird's eye that increases blood flow to the retina.

Alula

A set of three feathers on the second digit that functions as a wing slot to maintain lift at low speeds.

Ratites

A group of flightless birds, such as ostriches or emus.

Monogamy

A mating system consisting of one male and one female.

Polygyny

A form of polygamy where one male mates with more than one female.

Polyandry

A form of polygamy where one female mates with more than one male.

Precocial

Chicks that are hatched in an active state, such as the one-day-old ruffed grouse.

Altricial

Chicks that are hatched in a helpless state and require extensive parental care, such as the one-day-old meadowlark.