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Chapter Presentation
Visual Concepts
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Standardized Test Prep
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Chapter 34
Reptiles and Birds
Table of Contents
Section 1 The Reptilian Body
Section 2 Today’s Reptiles
Section 3 Characteristics and Diversity of Birds
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Chapter 34
Section 1 The Reptilian Body
Objectives
• Describe the key characteristics of reptiles.
• Relate a reptile’s ectothermic metabolism to its
activity level.
• Summarize the adaptations that enable reptiles to
live on land.
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Chapter 34
Section 1 The Reptilian Body
Key Characteristics of Reptiles
• Reptiles have a strong, bony skeleton. Most have two
pairs of limbs.They have toes with claws.
• Reptiles have an ectothermic metabolism.
• Reptiles have dry, scaly skin.
• Reptiles have amniotic eggs.
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Chapter 34
Section 1 The Reptilian Body
Key Features of Reptiles
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Chapter 34
Section 1 The Reptilian Body
Characteristics of Reptiles
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Chapter 34
Section 1 The Reptilian Body
Key Characteristics of Reptiles, continued
Ectothermic Metabolism
• Reptiles’ ectothermic metabolism is too slow to
generate enough heat to warm their bodies, so they
must absorb heat from their surroundings.
• A reptile’s body temperature is largely determined by
the temperature of its environment.
• At low temperatures, most reptiles become sluggish
and unable to function.
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Chapter 34
Section 1 The Reptilian Body
Changes in Lizard Body Temperature
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Chapter 34
Section 1 The Reptilian Body
Comparing Endotherms and Ectotherms
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Chapter 34
Section 1 The Reptilian Body
Water Retention
• Unlike amphibians, reptiles can be considered fully
terrestrial.
• Reptiles have adaptations that free them from the
water requirements of amphibians.
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Chapter 34
Section 1 The Reptilian Body
Water Retention, continued
Watertight Skin
• Reptiles have a skin made of light, flexible scales.
• These scales overlap and form a protective, almost
watertight skin that minimizes water loss.
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Chapter 34
Section 1 The Reptilian Body
Comparing Amphibian and Reptile Skin
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Chapter 34
Section 1 The Reptilian Body
Water Retention, continued
Watertight Eggs
• A reptile’s amniotic egg provides a moist environment
in which the embryo develops.
• An amniotic egg contains both a water supply and a
food supply.
• The amniotic egg’s tough shell keeps the egg from
drying out.
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Chapter 34
Section 1 The Reptilian Body
Amniotic Egg
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Chapter 34
Section 1 The Reptilian Body
Parts of an Amniotic Egg
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Chapter 34
Section 1 The Reptilian Body
Respiration
• Because reptiles are far more active than
amphibians, they have greater metabolic
requirements for oxygen.
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Chapter 34
Section 1 The Reptilian Body
Respiration, continued
Lungs
• Unlike the skin of an amphibian, the scaly skin of a
reptile does not permit gas exchange.
• The lungs of most reptiles have many internal folds,
greatly increasing their surface area.
• Reptiles have strong muscles attached to their rib
cages. These muscles help to move air into and out
of the lungs, increasing the lungs’ efficiency.
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Chapter 34
Section 1 The Reptilian Body
Alveolus/Alveoli
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Chapter 34
Section 1 The Reptilian Body
Respiration, continued
Heart
• In reptiles, the septum extends into the ventricle,
partly dividing it into left and right halves.
• As a result, oxygen is delivered to the body cells
more efficiently than in amphibians.
• Crocodiles have a heart with a completely divided
ventricle.
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Chapter 34
Section 1 The Reptilian Body
Reptilian Heart Structure
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Chapter 34
Section 1 The Reptilian Body
Reptile Heart
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Chapter 34
Section 1 The Reptilian Body
Reproduction
• Reptilian eggs are fertilized within the female, a
process called internal fertilization.
• Many reptiles are oviparous, meaning the young
hatch from eggs.
• Some species of snakes and lizards are
ovoviparous, which means the female retains the
eggs within her body until shortly before hatching, or
the eggs may hatch within the female’s body.
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Chapter 34
Section 2 Today’s Reptiles
Objectives
• Compare the four living orders of reptiles.
• Describe the timber rattlesnake’s adaptation for
locating and capturing prey.
• Compare the parental care of crocodilians with that
of other reptiles.
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Chapter 34
Section 2 Today’s Reptiles
Lizards and Snakes
• Snakes and lizards belong to the order Squamata.
• A characteristic of this order is a lower jaw that is
loosely connected to the skull. This enables snakes
and many lizards to swallow large prey.
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Chapter 34
Section 2 Today’s Reptiles
Types of Reptiles
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Chapter 34
Section 2 Today’s Reptiles
Characteristics of Snakes and Lizards
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Chapter 34
Section 2 Today’s Reptiles
Lizards and Snakes, continued
Lizards
• Most lizards are carnivores.
• Most lizards are small, measuring less than 30 cm (1
ft) in length.
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Chapter 34
Section 2 Today’s Reptiles
Lizards and Snakes, continued
Snakes
• The skeleton of snakes lacks a pectoral girdle, the
supporting bones for the bones of the forelimbs.
• Snakes do not have teeth suited for cutting and
chewing.
• Some snakes are constrictors, squeezing their prey
until it suffocates, then eating it. Other snakes kill
their prey with poisonous venom.
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Chapter 34
Section 2 Today’s Reptiles
External Structure of a Timber Rattlesnake
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Chapter 34
Section 2 Today’s Reptiles
Internal Structure of a Timber Rattlesnake
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Chapter 34
Section 2 Today’s Reptiles
Anatomy of a Snake
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Chapter 34
Section 2 Today’s Reptiles
Other Orders of Reptiles
• The remaining orders of living reptiles contain far
fewer species than the order Squamata does.
• There are about 250 or more species of turtles and
tortoises, all classified in the order Chelonia.
• There are about 25 species of crocodiles in the order
Crocodilia. There are only two species of tuataras in
the order Rhynchocephalia.
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Chapter 34
Section 2 Today’s Reptiles
Other Orders of Reptiles, continued
Turtles and Tortoises
• The bodies of turtles and tortoises are encased within
a hard, bony, protective shell.
• The carapace is the dorsal (top) part of the shell, and
the plastron is the ventral (bottom) portion.
• Turtles and tortoises lack teeth but have jaws
covered by sharp plates, which form powerful beaks.
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Chapter 34
Section 2 Today’s Reptiles
Characteristics of Turtles
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Chapter 34
Section 2 Today’s Reptiles
Carapace and Plastron
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Chapter 34
Section 2 Today’s Reptiles
Other Orders of Reptiles, continued
Crocodiles and Alligators
• Crocodiles and alligators are aggressive carnivores.
• They capture their prey by stealth, drawing it
underwater to be drowned and eaten.
• Unlike other living reptiles, crocodilians care for their
young after hatching.
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Chapter 34
Section 2 Today’s Reptiles
Characteristics of Crocodiles and Alligators
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Chapter 34
Section 2 Today’s Reptiles
Other Orders of Reptiles, continued
Tuataras
• Tuataras are lizardlike reptiles up to 70 cm (2 ft) long.
• The two living species of tuataras are members of the
genus Sphenodon and are native to New Zealand.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Objectives
• Summarize the key characteristics of birds.
• Describe how a bird’s feathers and bone structure
aid flight.
• Summarize how a bird’s lungs and heart are adapted
for high efficiency.
• Relate the structure of a bird’s feet and beak to its
habits and diet.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Key Characteristics of Birds
• Unlike reptiles, birds lack teeth and have a tail that is
greatly reduced in length.
• Like reptiles, birds have amniotic eggs. They also
have feet and legs that are covered with scales.
• Birds have feathers and forelimbs modified into
wings.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Characteristics of Birds
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Parts of a Bird Brain
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Characteristics of Birds
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Bird Adaptations for Flight
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Key Characteristics of Birds, continued
Feathers
• Feathers are modified reptilian scales. Contour
feathers cover the bird’s body and give adult birds
their shape.
• When a bird preens, it spreads oil from its preen
gland over its feathers, cleaning and waterproofing
them.
• Down feathers cover the body of young birds and
are found beneath the contour feathers of adults.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Contour Feather Structure
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Parts of a Feather
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Preening
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Key Characteristics of Birds, continued
Strong, Lightweight Skeleton
• The bones of birds are thin and hollow. Some of the
bones are fused, providing extra strength.
• Birds have a large breastbone with a prominent keel
for muscle attachment.
• Muscles used in flight are attached to the breastbone
and fused collarbones.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Avian Skeleton
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Anatomy of a Bird
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Key Characteristics of Birds, continued
Endothermic Metabolism
• Birds are endotherms, which means they generate
enough heat through metabolism to maintain a high
body temperature.
• Birds have a high rate of metabolism, which meets
the increased energy requirements of flight.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Key Characteristics of Birds, continued
Completely Divided Ventricle
• As in the crocodilian heart, the ventricle of the bird
heart is completely divided by a septum.
• The septum of the bird heart separates oxygen-rich
and oxygen-poor blood, meaning that oxygen is
delivered to the body cells more efficiently.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Avian Heart Structure
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Bird Heart
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Bird Digestive System
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Key Characteristics of Birds, continued
Highly Efficient Lungs
• Birds have a high demand for oxygen because they
use large amounts of energy when they fly.
• Air moves through a bird’s lungs in one direction. Air
sacs connected to a bird’s lungs act as holding tanks
to enable the one-way flow of air.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Avian Lung Structure
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
External Structure of Birds – Bald Eagle
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Internal Structure of Birds – Bald Eagle
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Bird Lungs
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Adaptations of Birds
• Different species of birds are adapted for different
ways of life.
• A bird’s beak (bill), legs, and feet reveal a great deal
about its habits and diet.
• Some species of birds are highly specialized, while
others are very flexible in their eating habits.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Beak Adaptations and Bird Diversity
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Foot Adaptations and Bird Diversity
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Adaptations of Birds, continued
Other Adaptations
• There are many orders of birds, each of which is
adapted to its particular living conditions.
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Avian Adaptations
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Chapter 34
Section 3 Characteristics and
Diversity of Birds
Types of Birds
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Chapter 34
Standardized Test Prep
Multiple Choice
The chart below shows the normal ranges of body
temperatures in five groups of reptiles. Use the chart to
answer questions 1–3.
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Chapter 34
Standardized Test Prep
Multiple Choice, continued
1. Which groups could probably best tolerate the
temperature extremes found in deserts?
A.
B.
C.
D.
Turtles, snakes, and crocodilians
Turtles, lizards, and snakes
Tuataras, turtles, and snakes
Tuataras and crocodilians
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Chapter 34
Standardized Test Prep
Multiple Choice, continued
1. Which groups could probably best tolerate the
temperature extremes found in deserts?
A.
B.
C.
D.
Turtles, snakes, and crocodilians
Turtles, lizards, and snakes
Tuataras, turtles, and snakes
Tuataras and crocodilians
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Chapter 34
Standardized Test Prep
Multiple Choice, continued
2. If a bar showing the body temperature range of birds
were added to this chart, the bar for birds would
partially overlap with the bar for
F.
G.
H.
J.
lizards.
tuataras.
crocodilians.
turtles.
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Chapter 34
Standardized Test Prep
Multiple Choice, continued
2. If a bar showing the body temperature range of birds
were added to this chart, the bar for birds would
partially overlap with the bar for
F.
G.
H.
J.
lizards.
tuataras.
crocodilians.
turtles.
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Chapter 34
Standardized Test Prep
Multiple Choice, continued
3. Which of these statements is supported by the data
in the chart?
A. Crocodilians have a greater body temperature
range than tuataras.
B. Turtles and snakes have similar body
temperature ranges.
C. Lizards always have a higher body temperature
than tuataras.
D. Some lizards can have a higher body
temperature than some crocodilians.
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Chapter 34
Standardized Test Prep
Multiple Choice, continued
3. Which of these statements is supported by the data
in the chart?
A. Crocodilians have a greater body temperature
range than tuataras.
B. Turtles and snakes have similar body
temperature ranges.
C. Lizards always have a higher body temperature
than tuataras.
D. Some lizards can have a higher body
temperature than some crocodilians.
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