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Chapter 34
Reptiles and Birds
Section 1: The Reptilian Body
Section 2: Today’s Reptiles
Section 3: Characteristics and Diversity of
Birds
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.
Section 1
The Reptilian Body
Key Characteristics of Reptiles
•Features Reptiles have a strong, bony skeleton.
•Ectothermic Metabolism Reptiles are ectothermic.
Section 1
The Reptilian Body
Water Retention
•Watertight Skin Reptiles have nearly watertight
skin, which enable them to be terrestrial animals.
•Watertight Eggs Reptiles have nearly watertight
eggs, which enable them to be terrestrial animals.
Section 1
The Reptilian Body
Respiration
•Lungs Reptiles have paired lungs that have a greater
surface area for gas exchange than the lungs of
amphibians.
•Heart Reptiles have a double-loop circulatory
system. Most have a ventricle that is partly divided
into right and left halves, resulting in incomplete
separation of oxygen-rich and oxygen-poor blood.
Section 1
The Reptilian Body
Reproduction
•Fertilization Reptilian fertilization is internal.
Section 2
Today’s Reptiles
Objectives:
•Compare the four living orders of reptiles.
•Describe the timber rattlesnake's adaptations for
locating and capturing prey.
•Compare the parental care of crocodilians with that
of other reptiles.
Section 2
Today’s Reptiles
Lizards and Snakes
•Snakes and Lizards Snakes and lizards (order
Squamata) share many characteristics, such as
periodic molting, but snakes have no legs.
Section 2
Today’s Reptiles
Other Orders of Reptiles
•Turtles and Tortoises The shells of turtles and
tortoises (order Chelonia) are made of fused plates of
bone covered with horny shields or leathery skin.
•Crocodiles and Alligators Unlike other reptiles,
crocodilians (order Crocodilia), care for their young
after hatching. They also have a completely divided
ventricle.
•Tuataras There are only two species of tuatara
(order Rhynchocephalia).
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.
Section 3
Characteristics and Diversity of Birds
Key Characteristics of Birds
•Endothermy Birds are endotherms. Their high rate
of metabolism helps them meet the large
requirements for flight.
•Feathers A bird’s contour feathers give the bird its
shape and aid flight. Its down feathers provide
insulation.
•Strong, Lightweight Skeleton The bones of birds
are thin and hollow, and many of them are fused; all
are adaptations for flight.
Section 3
Characteristics and Diversity of Birds
Key Characteristics of Birds continued
•Endothermic Metabolism Birds are endotherms;
that is, they generate enough heat through
metabolism to maintain a high body temperature.
•Completely Divided Ventricle The ventricle of the
bird heart is completely divided by a septum.
•Highly Efficient Lungs One-way airflow through
the lungs provides the large amounts of oxygen birds
need for flight.
Section 3
Characteristics and Diversity of Birds
Adaptations of Birds
•Adaptations Birds are adapted for different ways of
life, including beak, leg, and feet adaptations.