Chapter 42 Table of Contents Section 1 Origin and Evolution of Birds Section 2 Characteristics of Birds Section 3 Classification

Section 1 Origin and Evolution of Birds Chapter 42 Objectives Identify and describe seven major characteristics of birds. List three similarities between birds and dinosaurs. Describe the characteristics of Archaeopteryx. Summarize the two main hypotheses for the evolution of flight.

Chapter 42 Characteristics Section 1 Origin and Evolution of Birds Chapter 42 Characteristics There are seven characteristics all birds share Feathers Wings Lightweight, rigid skeleton Endothermic metabolism Unique respiratory system Beak Oviparity

Characteristics of Birds Section 1 Origin and Evolution of Birds Chapter 42 Characteristics of Birds

Section 1 Origin and Evolution of Birds Chapter 42 Evolution There are several similarities between birds and some dinosaurs: Flexible S-shaped neck Unique ankle joint Hollow bones

Chapter 42 Evolution, continued Section 1 Origin and Evolution of Birds Chapter 42 Evolution, continued The oldest known bird fossils are in the genus Archaeopteryx, which date from the late Jurassic Characteristics of Archaeopteryx Feathers on forelimbs, body and tail Hollow bones and a furcula (fused collarbones also called a wishbone) Teeth Claws on forelimbs Long, bony tail

Chapter 42 Evolution, continued Section 1 Origin and Evolution of Birds Chapter 42 Evolution, continued Archaeopteryx had characteristics of birds and dinosaurs.

Chapter 42 Evolution, continued Origin of Flight Section 1 Origin and Evolution of Birds Chapter 42 Evolution, continued Origin of Flight One hypothesis proposes that the ancestors of birds were tree dwellers that developed the ability to glide between trees. Another hypothesis suggests that the ancestors of birds were ground-dwelling and first used feathers to stabilize them when they leapt after prey.

Phylogenetic Diagram of Birds, Reptiles, and Mammals Section 1 Origin and Evolution of Birds Chapter 42 Phylogenetic Diagram of Birds, Reptiles, and Mammals

Adaptations for Flight Section 1 Origin and Evolution of Birds Chapter 42 Adaptations for Flight Click below to watch the Visual Concept. Visual Concept

Chapter 42 Objectives Describe the structure of a contour feather. Section 2 Characteristics of Birds Chapter 42 Objectives Describe the structure of a contour feather. Identify two modifications for flight seen in a bird’s skeletal system. Contrast the function of the gizzard with that of the crop. Trace the movement of air through the respiratory system of a bird. Explain the differences between altricial and precocial young.

Characteristics of Birds Section 2 Characteristics of Birds Chapter 42 Characteristics of Birds Click below to watch the Visual Concept. Visual Concept

Chapter 42 Feathers Section 2 Characteristics of Birds Feathers are modified scales that serve two primary functions: providing lift for flight and conserving body heat. Feathers develop from tiny pits in the skin called follicles. Feathers have a shaft, two vanes, barbs and barbules.

Chapter 42 Feathers, continued Section 2 Characteristics of Birds Chapter 42 Feathers, continued There are three basic types of feathers: Down feathers - soft, fluffy feathers that cover young birds and provide an insulating undercoat in adults Contour feathers - smooth feathers that give adult birds’ bodies a streamlined shape and provide insulation Flight feathers - specialized contour feathers located on the wings and tail that are long and rigid

Chapter 42 Feathers, continued Section 2 Characteristics of Birds Chapter 42 Feathers, continued Feathers are cared for by a process called preening. Preening occurs when birds use their beaks to rub their feathers with oil. The preen gland is located at the base of the tail and secretes oils that keep feathers healthy and waterproof. Birds periodically shed and regrow their feathers in a process called molting.

Contour Feather Structure Section 2 Characteristics of Birds Chapter 42 Contour Feather Structure

Chapter 42 Parts of a Feather Section 2 Characteristics of Birds Click below to watch the Visual Concept. Visual Concept

Chapter 42 Preening Section 2 Characteristics of Birds Click below to watch the Visual Concept. Visual Concept

External Structure of Birds—Bald Eagle Section 2 Characteristics of Birds Chapter 42 External Structure of Birds—Bald Eagle

Chapter 42 Skeleton and Muscles Section 2 Characteristics of Birds Chapter 42 Skeleton and Muscles The avian skeleton is light and strong. Bones are thin and hollow. Many bones are fused, which makes the skeleton more rigid than that of a reptile or mammal. A large keel-shaped sternum allows attachment of large flight muscles. The pygostyle, fused terminal vertebrae, supports the tail feathers.

Section 2 Characteristics of Birds Chapter 42 Avian Skeleton

Skeleton and Muscles, continued Section 2 Characteristics of Birds Chapter 42 Skeleton and Muscles, continued Flight involves complex wing movements. Each movement uses a different set of muscles. Birds have large, powerful flight muscles in the breast and wings. In some birds, flight muscles account for up to 50% of the body weight.

Chapter 42 Metabolism Birds are endothermic. Section 2 Characteristics of Birds Chapter 42 Metabolism Birds are endothermic. Birds have a very high metabolic rate. Rapid breathing and digestion of large quantities of food support this high metabolic rate. Birds’ digestive and respiratory systems have evolved to support a high metabolism.

Digestive and Excretory Systems Section 2 Characteristics of Birds Chapter 42 Digestive and Excretory Systems The avian digestive system consists of: Beak - breaks open or tears apart food Esophagus - passage from the mouth to the crop Crop - stores and moistens food Stomach - consists of two parts proventriculus - acids and digestive enzymes begin breaking down food gizzard - kneads and crushes food aided by stones which the bird swallows Small intestine - absorbs nutrients Large intestine - absorbs water Cloaca - eliminates wastes from the body

Chapter 42 Bird Digestive System Section 2 Characteristics of Birds Click below to watch the Visual Concept. Visual Concept

Digestive and Excretory Systems, continued Section 2 Characteristics of Birds Chapter 42 Digestive and Excretory Systems, continued The avian excretory system is efficient and lightweight. Birds have two kidneys that filter nitrogenous wastes. Birds do not have a urinary bladder. Birds excrete concentrated uric acid, which conserves water. Uric acid mixes with feces and is excreted through the cloaca.

Chapter 42 Respiratory System Section 2 Characteristics of Birds Chapter 42 Respiratory System The avian respiratory system is highly efficient and allows birds to maintain a high metabolic rate. Air sacs connected to the lungs provide a constant flow of oxygenated air to the lungs. This also allows birds to function at high altitudes.

Section 2 Characteristics of Birds Chapter 42 Avian Lung Structure

Chapter 42 Bird Lungs Section 2 Characteristics of Birds Click below to watch the Visual Concept. Visual Concept

Chapter 42 Circulatory System Section 2 Characteristics of Birds Chapter 42 Circulatory System The avian circulatory system is similar to that of both crocodiles and mammals. Birds have a four chambered heart. Deoxygenated blood is completely separated from oxygenated blood in the heart. Birds have a relatively rapid heartbeat. Unlike mammals, avian red blood cells have nuclei.

Section 2 Characteristics of Birds Chapter 42 Avian Heart Structure

Chapter 42 Bird Heart Section 2 Characteristics of Birds Click below to watch the Visual Concept. Visual Concept

Nervous System and Sense Organs Section 2 Characteristics of Birds Chapter 42 Nervous System and Sense Organs Birds have large brains relative to their body size. The cerebellum, which controls flight related functions, is large. The cerebrum, which controls complex behavior, is also well developed. The optic lobes are also very large.

Chapter 42 Parts of a Bird Brain Section 2 Characteristics of Birds Click below to watch the Visual Concept. Visual Concept

Nervous System and Sense Organs, continued Section 2 Characteristics of Birds Chapter 42 Nervous System and Sense Organs, continued Birds have very good vision. Vision is important for flight and feeding. Most birds have strong color vision. Some birds have eyes located near the sides of the head, which provide a wide field of vision. Predatory birds have eyes that are more forward-facing, which provides depth perception.

Nervous System and Sense Organs, continued Section 2 Characteristics of Birds Chapter 42 Nervous System and Sense Organs, continued Birds have good hearing. Hearing is important for songbirds and nocturnal birds. Nocturnal predators rely on hearing to locate prey. Birds lack external ears. Owls have feathers around their ear openings that direct sound into the ear.

Chapter 42 Reproduction Male: Section 2 Characteristics of Birds Chapter 42 Reproduction Male: Sperm is produced in two testes, located anterior to the kidneys. Sperm passes through small tubes called vasa deferentia (singular vas deferens). Sperm exits through the cloaca.

Reproduction, continued Section 2 Characteristics of Birds Chapter 42 Reproduction, continued Female: Eggs are produced in a single ovary, located on the left side of the body. Eggs are released by the ovary and pass into a funnel shaped tube called the oviduct. Eggs are fertilized in the oviduct. In the oviduct, eggs are encased in a protective covering and a shell. Eggs are released through the cloaca.

Reproduction, continued Section 2 Characteristics of Birds Chapter 42 Reproduction, continued Nest building and parental care Birds usually lay their eggs in a nest. One or both parents warm (incubate) the eggs and guard the nest. Birds sit on their eggs and cover them with a thickened featherless patch of skin called the brood patch. Birds usually provide extensive parental care.

Reproduction, continued Section 2 Characteristics of Birds Chapter 42 Reproduction, continued Birds have two general patterns for rearing young Precocial: Young incubate for long periods. Young can walk, swim, and feed as soon as they hatch. This pattern is most often seen in ground-nesting birds. Altricial: Eggs hatch quickly. Young hatch blind, featherless, and helpless and require extensive parental care. This pattern is most often seen in birds that nest above ground.

Internal Structure of Birds—Bald Eagle Section 2 Characteristics of Birds Chapter 42 Internal Structure of Birds—Bald Eagle

Chapter 42 Anatomy of a Bird Section 2 Characteristics of Birds Click below to watch the Visual Concept. Visual Concept

Chapter 42 Migration Section 2 Characteristics of Birds Migration is the seasonal movement of animals from one habitat to another habitat. Many birds nest in temperate regions, and spend winters in tropical regions. Bird migration patterns are studied by ornithologists - biologists who study birds. Birds may use landmarks, star position, sun position, Earth’s magnetic field, changes in air pressure, or low-frequency sounds to navigate during migration. Many species rely on fat reserves for energy during migration. Some species gather and feed along the migration route at places called staging sites.

Section 3 Classification Chapter 42 Objectives Describe the relationship between beak shape and diet in birds. List 10 major orders of living birds, and name an example of each order. Describe the function of the syrinx.

Section 3 Classification Chapter 42 Diversity Beak and foot adaptation reveal information about a bird’s habitat and diet, for example: Predators: powerful, hooked beaks and sharp talons (claws) Seed eaters: strong wide beaks, small feet for perching Nectar feeders: long thin beaks Flightless birds: strong legs for walking and running

Section 3 Classification Chapter 42 Avian Adaptations

Beak Adaptations and Bird Diversity Section 3 Classification Chapter 42 Beak Adaptations and Bird Diversity Click below to watch the Visual Concept. Visual Concept

Foot Adaptations and Bird Diversity Section 3 Classification Chapter 42 Foot Adaptations and Bird Diversity Click below to watch the Visual Concept. Visual Concept

Chapter 42 Diversity, continued Section 3 Classification Chapter 42 Diversity, continued Taxonomists divide birds into about 23 orders. Morphology (body form), protein sequences, DNA sequence, and other evidence are used to classify birds. Ten of the most familiar orders are listed below. Anseriformes Strigiformes Apodiformes Poittaciformes Piciformes Passeriformes Columbiformes Ciconiiformes Galliformes Struthioniformes

Chapter 42 Diversity, continued Order Anseriformes Section 3 Classification Chapter 42 Diversity, continued Order Anseriformes Includes swans, geese, ducks and other waterfowl Webbed feet Flattened bill Precocial young

Chapter 42 Diversity, continued Order Strigiformes Includes owls Section 3 Classification Chapter 42 Diversity, continued Order Strigiformes Includes owls Nocturnal Keen vision with forward facing eyes Predators Keen hearing

Chapter 42 Diversity, continued Order Apodiformes Section 3 Classification Chapter 42 Diversity, continued Order Apodiformes Includes hummingbirds and swifts Small birds with tiny feet Fast flying, some can hover Insectivores and nectar feeders

Chapter 42 Diversity, continued Section 3 Classification Order Psittaciformes Includes parrots, parakeets, macaws, cockatoos, cockatiels and their relatives Seed and fruit eaters Strong hooked beaks for opening seeds Two forward facing and two backward facing toes, for climbing and perching Vocal birds, some can mimic human speech

Chapter 42 Diversity, continued Order Piciformes Section 3 Classification Chapter 42 Diversity, continued Order Piciformes Includes tree dwelling birds such as woodpeckers, honeyguides and toucans. All nest in tree cavities Two forward and two backward facing toes Woodpeckers have sharp, chisel-like bills Toucans are fruit eaters and have large bills

Chapter 42 Diversity, continued Order Passeriformes Section 3 Classification Chapter 42 Diversity, continued Order Passeriformes Includes robins, warblers, blue jays, wrens, and other common North American birds Perching birds with three toes forward and one backward, with enlarged rear toe for grip Seed, fruit, insect, and nectar feeders Many are songbirds. Males use elaborate songs to attract females. The song is produced in a structure called the syrinx.

Chapter 42 Diversity, continued Order Columbiformes Section 3 Classification Chapter 42 Diversity, continued Order Columbiformes Includes pigeons and doves Large breasts and small heads Fruit or grain eaters with small beaks and short legs Both sexes feed young with nutritious fluid produced in the crop, called crop milk

Chapter 42 Diversity, continued Order Ciconiiformes Section 3 Classification Chapter 42 Diversity, continued Order Ciconiiformes Includes herons, storks, ibises, egrets, raptors, vultures and penguins Highly diverse group Many are wading birds that eat fish and frogs, with long legs, long neck, and long bill All are carnivorous

Chapter 42 Diversity, continued Order Galliformes Section 3 Classification Chapter 42 Diversity, continued Order Galliformes Includes turkeys, chickens, pheasants, grouse, and quails Commonly called fowl Usually plump bodies, may be poor fliers Grain and insect eaters Precocial young

Chapter 42 Diversity, continued Order Struthioniformes Section 3 Classification Chapter 42 Diversity, continued Order Struthioniformes Includes ostriches, emus, rheas, and cassowaries Includes the worlds largest birds Fightless birds with small wings and long powerful legs for running Ostriches can reach speeds of 55 mph Ostriches have two toes per foot

Chapter 42 Types of Birds Section 3 Classification Click below to watch the Visual Concept. Visual Concept