Download Chapter 32: Reptiles and Birds

Chapter 32: Reptiles and Birds
Section 3: Birds
Birds

About ________________ living species belonging to more than ___________ families

There were even more kinds of birds in the past

Paleontologists estimate that more than ________________________________ of birds
have become extinct since the _______________________________________
What Is a Bird?

_________________ are endothermic reptile-like animals with an outer covering of
feathers, two legs used for walking or perching, and front limbs modified into wings
that usually do not have useful claws

The single most important feature that distinguishes birds from reptiles is
_______________________

Feathers help birds ___________ and also keep them _________________

Birds have several different kinds of feathers

___________________________________ are large feathers that cover a bird’s body and
wings
o Used for ____________________
o Contain ___________________ and ________________________
o _____________________________

_____________________________________ grow underneath and between the contour
feathers
o ____________________, __________________, and ______________________
o Trap warm air close to a bird’s body

_____________________________________ are important to birds that live on or in
water
o ______________________________________
Evolution of Birds

The
first
fossil
ever
found
of
an
early
birdlike
animal
is
called
_____________________________________ and dates from late in the Jurassic Period

Its skeleton looks much like a ________________________________________________

Had ____________________ in its beak

Had ________________________________ on its wings

There is much controversy over which fossils are those of birds and when birds first
appeared on Earth
Form and Function in Birds

Many characteristic features of birds differ dramatically among species adapted to different
ways of life
o _________________________________________________________________

It is important to study birds that live in _________________________________________
and examine the adaptations they show
Feeding

Birds have high metabolic rates and burn many calories just to keep warm

For that reason, birds need to eat _____________________________________________

The digestive system of birds shows specializations for carnivorous and herbivorous diets

Many birds have organs called ________________ and _________________________

The crop is an enlarged area of the esophagus, where food can be
_________________________________________________ before it enters the stomach

The gizzard is a muscular part of the stomach that often contains small bits of
______________________ swallowed by a bird
o Grinds the gravel and food together
_______________________________________________________ and

makes them easier to digest
Respiration

Extremely efficient in taking in _________________________ and eliminating
___________________________________________

Bird
lungs
are
connected
at
both
the
anterior
and
posterior
to
large
into
the
________________________ in the body cavity and bones

When a bird inhales, air travels through passageways that lead into the lungs

Some
stays
in
the
lungs,
however,
__________________________________________
most
goes

When a bird exhales, air from the posterior air sacs passes into the lungs for
_______________________________________

Birds are able to remove oxygen from air when they inhale as well as when they exhale
Internal Transport

_______________________________________________ and two separate circulatory
loops

One half of the heart receives oxygen-poor blood from the body and pumps this blood to
the lungs

Oxygen-rich blood returns to the other side of the heart to be pumped throughout the rest
of the body

This system ensures that oxygen collected by the lungs is distributed with maximum
efficiency

A bird’s heart beats ___________________________
o From 150 to more than 1000 beats per minute
Excretion

Eliminate nitrogenous waste by filtering them from the blood in the ___________________

Urine flows to the ____________________ through the ____________________

Most water is reabsorbed in the cloaca, leaving __________________________________
in a white paste like form
o ___________________________________

Bird
species
that
are
surrounded
by
sea
water
have
special
_____________________________ near their eyes
o Work like an extra pair of kidneys, except they specialize in secreting
_________________
Response

Birds are quite ______________________________

Cerebrum controls behaviors such as flying, nest building, care of young, courtship, and
mating

Cerebellum and medulla are much like those of reptiles

Extraordinary well-developed _________________ because of large optic lobes in the
brain

The senses of taste and smell are not well developed
o ____________________________________________

Lack external ________________

Some use a _______________________________________ to navigate
o Operates like a built-in compass, responding to Earth’s magnetic field
Movement

Travel through different environments with wings, bodies, legs, and feet adapted for
various types of locomotion

Many variations in bird wings, depending on whether the animals soar like eagles, flap
their wings steadily like robins, or hover in place like hummingbirds

Bones are ______________________ so that the weight carried in fight is less

Large chest muscles that attach directly to the sternum

Many birds use their flying ability to ___________________________ between summer
breeding grounds in the North and winter resting grounds in the South or the tropics

A number of birds have lost their ability to fly
o __________________________________________________
Reproduction

Similar to that of reptiles

Reproductive tracts open to the _______________________

Male birds have no external reproductive organs

Instead, mating birds press the lips of their cloacas close together to
______________________________________ from male to female

Most birds ______________________________________________ until they hatch

The
time
between
laying
and
hatching
varies
among
species
from
____________________ to more than ______________________

When a chick is ready to hatch, it uses a small ____________________________ on its
bill to make a hole in the shell

Some birds are able to take care of themselves as soon as they hatch

Other newly hatched birds are blind and totally helpless when they hatch

Birds have fascinating courtship and mating behaviors

Some species ________________________________

Other pair up only briefly to mate
How Birds Fit into the World

Serve as ________________________________ for a number of plants

Eat extraordinary numbers of __________________________

Down feathers are good insulators

_________________________________ around the world

Raising them is part of the economy in many countries

Healthful source of _____________________

Because domestic strains of chickens and turkeys do not fly, their chest muscles are
seldom
used,
making
this
part
of
the
bird
the
juicy
and
tender
____________________________

The leg and thigh muscles of these birds, used constantly for walking and running, are the
____________________________