Birds

Specialized Bird Features Wings

Feathers Mating Asserting dominance Regulation of body

temperature Camouflage

Countershading Flight

Specialized Bird Features Bones

Pneumatization

Specialized Bird Features

Beaks

Feet Number of toes Size Talons/lack of talons Webbed

Feathers Modified scales Extension of dermis

Primaries Long, found at the tip of the wing Allow for lift during flight

Secondaries Shorter, near middle of wing

Retrices Tail feathers

Skin

Thin and loose

Uropygial gland Secretes oil used to preen feathers

External Features Crown Nape Beak (upper and lower) External nares External auditory meatus Breast Abdomen Limbs

Upper – wings, specialized for flight Lower – specialized for walking upright and perching

Hallux (back toe/heel)

Tail (with feathers)

Skeletal Adaptations

Sternum Enlarged to support muscles used for flight

Synsacrum Fused lower vertebrae and sacrum/coccyx

Muscle adaptations for flight

Pectoralis; Supracoracoideus

Digestive System Organs Same similar organ

structure and order as other vertebrates

Digestive System Crop

At the base of the esophagus

Food storage Proventriculus: “true

stomach” Site of chemical

digestion Gizzard

After the “true stomach” to break down and mix food with digestive enzymes

Respiratory Adaptations Air sacs extend

from the lungs

Syrinx Lower end of the

trachea Contains internal

membranes Produces bird calls

Respiratory Adaptations Air sacs:

Increase amount of air available

More oxygen for higher metabolism

Heart and the Circulatory System

Endothermic 4 chambered heart

Systemic and Pulmonary Circuits

Circulatory System

Heart

Excretory System Simplified

Kidneys Uric acid for excretion Lack of urinary bladder

Reproductive System Simplified reproductive system

Male Tesis – oval shaped, above kidneys

Female One ovary

Left side

Both lead to cloaca

Reproduction Internal fertilization Females can store sperm for later fertilization

Will release eggs from the ovary sporadically Some species possess a calcified shell –

chickens

Amniotic egg Amnion Chorion Allantois Yolk sac

Amniotic Egg