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

Chapter 42
Birds
Table of Contents
Section 1 Origin and Evolution of Birds
Section 2 Characteristics of Birds
Section 3 Classification
Chapter 42
Section 1 Origin and Evolution of
Birds
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
Section 1 Origin and Evolution of
Birds
Characteristics
There are seven characteristics all birds share
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Feathers
Wings
Lightweight, rigid skeleton
Endothermic metabolism
Unique respiratory system
Beak
Oviparity
Chapter 42
Section 1 Origin and Evolution of
Birds
Characteristics of Birds
Chapter 42
Section 1 Origin and Evolution of
Birds
Evolution
There are several similarities between birds and
some dinosaurs:
• Flexible S-shaped neck
• Unique ankle joint
• Hollow bones
Chapter 42
Section 1 Origin and Evolution of
Birds
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
Section 1 Origin and Evolution of
Birds
Evolution, continued
Archaeopteryx had characteristics of birds and dinosaurs.
Chapter 42
Section 1 Origin and Evolution of
Birds
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.
Chapter 42
Section 1 Origin and Evolution of
Birds
Phylogenetic Diagram of Birds, Reptiles, and
Mammals
Chapter 42
Section 1 Origin and Evolution of
Birds
Adaptations for Flight
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Chapter 42
Section 2 Characteristics of
Birds
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.
Chapter 42
Section 2 Characteristics of
Birds
Characteristics of Birds
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Chapter 42
Section 2 Characteristics of
Birds
Feathers
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
Section 2 Characteristics of
Birds
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
Section 2 Characteristics of
Birds
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.
Chapter 42
Section 2 Characteristics of
Birds
Contour Feather Structure
Chapter 42
Section 2 Characteristics of
Birds
Parts of a Feather
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Chapter 42
Section 2 Characteristics of
Birds
Preening
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Chapter 42
Section 2 Characteristics of
Birds
External Structure of Birds—Bald Eagle
Chapter 42
Section 2 Characteristics of
Birds
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.
Chapter 42
Avian Skeleton
Section 2 Characteristics of
Birds
Chapter 42
Section 2 Characteristics of
Birds
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
Section 2 Characteristics of
Birds
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.
Chapter 42
Section 2 Characteristics of
Birds
Digestive and Excretory Systems
The avian digestive system consists of:
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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
Section 2 Characteristics of
Birds
Bird Digestive System
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Chapter 42
Section 2 Characteristics of
Birds
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
Section 2 Characteristics of
Birds
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.
Chapter 42
Section 2 Characteristics of
Birds
Avian Lung Structure
Chapter 42
Section 2 Characteristics of
Birds
Bird Lungs
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Chapter 42
Section 2 Characteristics of
Birds
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.
Chapter 42
Section 2 Characteristics of
Birds
Avian Heart Structure
Chapter 42
Section 2 Characteristics of
Birds
Bird Heart
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Chapter 42
Section 2 Characteristics of
Birds
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
Section 2 Characteristics of
Birds
Parts of a Bird Brain
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Chapter 42
Section 2 Characteristics of
Birds
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 forwardfacing, which provides depth perception.
Chapter 42
Section 2 Characteristics of
Birds
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
Section 2 Characteristics of
Birds
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.
Chapter 42
Section 2 Characteristics of
Birds
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.
Chapter 42
Section 2 Characteristics of
Birds
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.
Chapter 42
Section 2 Characteristics of
Birds
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 groundnesting 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.
Chapter 42
Section 2 Characteristics of
Birds
Internal Structure of Birds—
Bald Eagle
Chapter 42
Section 2 Characteristics of
Birds
Anatomy of a Bird
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Chapter 42
Section 2 Characteristics of
Birds
Migration
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 lowfrequency 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.
Chapter 42
Section 3 Classification
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.
Chapter 42
Section 3 Classification
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
Chapter 42
Section 3 Classification
Avian Adaptations
Chapter 42
Section 3 Classification
Beak Adaptations and Bird Diversity
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Chapter 42
Section 3 Classification
Foot Adaptations and Bird Diversity
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Chapter 42
Section 3 Classification
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.
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Anseriformes
Strigiformes
Apodiformes
Poittaciformes
Piciformes
Passeriformes
Columbiformes
Ciconiiformes
Galliformes
Struthioniformes
Chapter 42
Section 3 Classification
Diversity, continued
Order Anseriformes
• Includes swans, geese, ducks and other
waterfowl
– Webbed feet
– Flattened bill
– Precocial young
Chapter 42
Section 3 Classification
Diversity, continued
Order Strigiformes
• Includes owls
– Nocturnal
– Keen vision with forward facing eyes
– Predators
– Keen hearing
Chapter 42
Section 3 Classification
Diversity, continued
Order Apodiformes
• Includes hummingbirds and swifts
– Small birds with tiny feet
– Fast flying, some can hover
– Insectivores and nectar feeders
Chapter 42
Section 3 Classification
Diversity, continued
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
Section 3 Classification
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
Section 3 Classification
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
Section 3 Classification
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
Section 3 Classification
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
Section 3 Classification
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
Section 3 Classification
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
Section 3 Classification
Types of Birds
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