Preview the Selection
by looking at the photographs,
illustrations, captions, and
graphics to predict what the
selection will be about.
by comparing my experiences
with what I’m reading.
by using the
in the selection
Going, Going, Gone
[ 138 ]
Endangered or Extinct?
the strategies the strategies
in the selection in the selection
Valuing “Varmints” DDT and the Peregrine Falcon
page 157 page 169
[ 139 ]
Preview the Selection
by looking at the photographs, illustrations,
captions, and graphics to predict what the
selection will be about.
The strategy says to preview the selection to
predict what the selection will be about. The
photographs, captions, and graphics are about
animals from around the world. Several graphics
and captions mention the words “endangered” and
“extinct.” I predict the selection will discuss animals
that are endangered or extinct. Now I’m ready to
read and find out if my prediction is right.
by comparing my experiences with what I’m
The strategy says to make connections by compar-
ing my experiences with what I’m reading. I will stop
and think about this strategy every time I come to a
red button like this .
[ 140 ]
Hua Mei, the first surviving A model of the extinct dodo
giant panda born in a
North American zoo
In the 1500s sailors found a huge, clumsy, flightless bird
on the Mauritius [maw•rish•uhs] Islands in the Indian
Ocean. The dodo couldn’t move very fast and it couldn’t fly.
Animals that the sailors brought with them hunted and
Vo • cab • u • lar • y
killed the dodos. Whenever the sailors wanted food, they extinct (ik•stingkt)—
clubbed the birds. By 1680 the dodos became extinct. no longer living
[ 141 ]
In August of 1999, the birth of Hua Mei [hwah may] at
the San Diego Zoo was reason for celebration around the
world. Why all the excitement? Scientists believe there are
Make Connections just 1,000 giant pandas left in the wild and about 120 in
by comparing my captivity. Bamboo, the sole food of giant pandas in the
experiences with what wild, is scarce. The destruction of the bamboo forests in
China has caused the near-extinction of the giant panda.
My Thinking Without intervention, the only giant pandas left will be
My dog has really those born in zoos.
long, thick fur.
My dad says it is
because the region where the
What Is Extinction?
dog breed comes from is Plants and animals on our planet have become extinct
cold. The dogs use the fur to since the earth began. Some scientists believe that extinc-
keep warm. I understand tion is a natural process. As one species disappears,
what it means to adapt. another replaces it. This development takes place over
millions of years. It creates a natural biological variety of
living things. For all the species that we know today, there
are thousands of others that lived millions of years ago.
These extinct species are all gone. Paleontologists know
this because they study the fossil record of plants and
Vo • cab • u • lar • y animals. When a fossil no longer appears, the scientists
assume this species became extinct. No extinct animal or
intervention plant has ever reappeared. During the history of the earth,
(in•tuhr•ven•shuhn)—the act masses of animals and plants have become extinct within
of coming in to help
a short period of time. These mass extinctions have hap-
species (spee•sheez)— pened five times. Today we are in the sixth period of mass
a group of living things that
are alike in certain ways
extinction. What caused this to happen in the past? Why is
it happening today?
scientists who study ancient Ecosystems
forms of life, such as fossils
All living things, plants or animals, depend on other
fossil (fos•uhl)—the hard- living things to stay alive. Every living thing from one-
ened remains of a plant or
animal celled amoebae to giant dinosaurs is part of an ecosystem
(a group of living things in an environment). Over mil-
tiny organisms that change lions of years, living things adapt to their environment and
form become part of ecosystems. When something disrupts the
environment ecosystem, the living thing does one of two things: It
(en•vy•ruhn•muhnt)—the adapts or becomes extinct. When one animal or plant dies,
conditions and surroundings in other animals that depend on it for food can die, too.
which something lives When the ecosystem is disrupted, this leads to the extinc-
tion of some species within it.
[ 142 ]
Creatures with the greatest impact on others in an
ecosystem are called keystone species. The alligator, once
an endangered species in the United States, is a keystone
species in its swamp ecosystem. Alligators dig holes to rest
and to stay cool. These fill with water and become small
ponds. Plants and marine animals begin to inhabit the
ponds. The alligator makes a nest of sticks and mud,
which soon becomes an island where plants and trees
grow. Birds nest in the trees. When the alligator was hunt-
ed to near extinction, its ecosystem was almost destroyed.
Without the alligators, there were no ponds and islands.
No ponds and islands meant loss of habitat for other
An alligator in
its habitat on
Causes of Five Periods of Mass Extinction
Throughout history the loss of keystone species and Vo • cab • u • lar • y
ecosystems led to the gradual extinction of many species. habitat—a place where an
But there were also periods of mass extinction when animal or plant is normally
thousands of plants and animals disappeared quickly from found
the earth. Until A.D. 1600, major changes in the geology geology (jee•ol•uh•jee)—
and climate of the earth caused major changes in the the structure of the earth’s
[ 143 ]
The earth is not a quiet planet. It is always changing.
Earthquakes show that the land is shifting. Glaciers
[glay•shuhrz] are constantly moving all around the world.
Make Connections Floods and storms wash away forests and grasslands.
by comparing my Violent changes in the land, sea, or climate can cause a
experiences with what loss of ecosystems. Loss of ecosystems in turn causes
habitats for plants and animals to vanish. As a result,
My Thinking many plants and animals became extinct. Mass extinctions
My grandparents happened during dramatic changes in the earth.
live on the East
Coast, which has
The Ordovician [or•duh•vish•uhn] extinction happened
eroded because of the
weather. So I understand
about 440 million years ago. Scientists think this was
the idea of decreased caused by a sudden cooling of the earth’s surface. This
habitat for the animals resulted in widespread glaciation. Lands that had been
that live there. tropical were covered with ice sheets and glaciers. This
caused between 20 and 50 percent of the species on Earth
to become extinct.
During the late
about 360 million
years ago, scientists
believe the same
As the seas cooled,
many fish and
died. About 1/4 of all
million years ago,
the Permian extinc-
During that period,
half of all living
Vo • cab • u • lar • y things disappeared.
glaciation Some scientists
(glay•shee•ay•shuhn)—being believe that the earth
covered with sheets of ice was hit by a large
invertebrates object from space.
(in•vur•tuh•brits)—animals Others believe the
that have no backbone Part of this Alaskan glacier is breaking off
and falling into the ocean.
[ 144 ]
same climatic changes as the two previous periods were
responsible. However, this time there was a warming of
the earth’s surface.
Volcanic eruptions and asteroid impacts seem to have
caused the Late Triassic [trye•as•ik] extinction. About 1/3
of all plants and animals on Earth disappeared. Dinosaurs
the Triassic extinc- Some Endangered Animals Today
tion. But during the
[kri•tay•shuhs] Giant Panda
extinction, they too (China)
disappeared. There California
is evidence that this
was caused by a Bear
Scientists think that
a comet hit the
earth in Central
only 15 percent of
all the species
disappeared during Cheetah
this event, the
dinosaurs were one
Causes of the Sixth Mass Extinction
The earth is now in a period called the Holocene
[hol•uh•seen]. This period began 65 million years ago.
Gradual extinction has been taking place for all that time.
In the past 400 years, however, a mass extinction seems
to have been going on. Its cause is not a meteor, glacia-
tion, change in sea level, or global cooling. Its cause is
anthropogenic. That is, it has been caused by humans.
Humans deliberately or inadvertently are causing other Vo • cab • u • lar • y
species to become extinct. People have destroyed habitats asteroid (as•tuh•roid)—one
and polluted the globe. They have hunted and collected of many small celestial bodies
plants and animals. People have introduced non-native that orbit the sun
plants and animals to regions where they did not belong. anthropogenic
All of these are contributing to the loss of ecosystems. (an•thruh•puh•jen•ik)—
caused by humans
[ 145 ]
In the past 50 years, people all over the world have
become aware of what extinction means. By placing ani-
Make Connections mals and plants on an endangered species list, people hope
by comparing my to save them from extinction. In the 1980s, species were
experiences with what
becoming extinct at the rate of one a day, or 365 per year.
Today it is 2.7 a day. That’s about 1,000 per year! In the
My Thinking previous 600 million years, the rate was 10 per year.
There are a lot Animals that are near extinction include every species of
of deer in our whale, the African cheetah, the Arctic polar bear, and oth-
Maybe it is because we
ers. Plants, insects, and birds too numerous to list are
have built our houses in endangered. In some parts of the world, one small plant of
their ecosystem, and they a species is all that survives. Why has this happened?
have lost their habitat. There are many causes.
Expansion Causes Habitat Destruction
As the human population of the earth has grown,
so has the need for farmland. More farms and people
have led to destruction of
many animals’ and plants’
natural habitats. As a
complex relationships of
plants, animals, and their
One of the primary
habitats being destroyed
is the rain forest. In the
Amazon region alone,
more than one third of
the rain forests has been
destroyed. The habitat
of hundreds of songbirds
has gone with it.
Illegal logging of the rain forest
near La Amistad Biosphere
Reserve in Costa Rica
[ 146 ]
Several large felines are endangered. Removing the forest
canopy and burning the land add to the pollution of the
atmosphere. In 1987 biologists counted 1,000 golden toads
in the rain forest of Central America. Today they cannot Make Connections
find any. by comparing my
Another habitat being destroyed is the wetland. People experiences with what
build houses and roads right through wetlands. With the
destruction of wetlands, habitats for small marine animals My Thinking
that are part of much larger ecosystems are disappearing. I remember seeing
These include frogs, toads, salamanders, and many footage of an oil
microorganisms. Birds that live in wetlands need to seek tanker spill on
other places to nest. Animals that come to drink in marshy television. Volunteers
areas are deprived of water. With no place to hide, eat, or were trying to save birds
that were covered by oil
drink, an animal can soon disappear.
and were unable to fly.
As people build cities, houses, factories, and roads, the
air is filled with smoke that is poisonous to plants and ani-
mals. People dump toxic chemicals in rivers. The chemi-
cals are swallowed by fish and other marine creatures.
Birds eat the fish and die. DDT, a pesticide used in the
1940s and 1950s, almost made several species of birds
extinct. The bald eagle, whose eggshells were made too
thin by DDT, almost disappeared in the 1960s. Since this
bird was placed on the endangered species list, it has
renewed itself. In 1999, the bald eagle was removed from
the endangered species list.
Ecological disasters such as
fires, oil spills, wars, and glob-
al warming—caused mostly by
humans—are also causing
many species to rapidly
Vo • cab • u • lar • y
members of the cat family
covering of trees overhead
The bald eagle is no longer on
—tiniest living things
the endangered species list.
[ 147 ]
The Effect of Hunting and Collecting
As people hunted animals for food, their fur, or their
exotic skins or feathers, they did not realize that these
animals could disappear.
For example, in the early 1800s, there were so many
passenger pigeons that flocks of them would block out the
sun for as long as 8 hours at a time. By 1914, these birds
were extinct. One reason is that people hunted them
Bison like these were because they were delicious to eat. People killed many
brought back from the others because they thought the birds were pests.
edge of extinction. Other animals have
been overhunted, too.
In 1800, there were
more than 60 million
bison in the United
States. By 1889, there
were about 800. The
bison had provided
food, clothing, and
shelter for the settlers
as they moved west.
No one believed bison
No one understood
that they couldn’t
reproduce as fast as
they were killed. When
realized the danger
of losing the last bison,
people intervened. Today, there are about 260,000 bison
in the United States.
Another Cause: Introduced Species
Vo • cab • u • lar • y As people have traveled around the globe, they have
brought animals and plants with them. Often these species
conservationists are introduced to habitats that are not suitable for them.
people who work to protect
Sometimes the result is a loss of ecosystems for the native
wildlife and the environment plants and animals.
In New England, people planted a flower called
—came in to change a situation Purple Loosestrife. It grows quickly and looks very pretty,
[ 148 ]
a New England pest
by comparing my
but it takes over the ponds experiences with what
and wetlands where it lives. I’m reading.
Because it is killing off
other plants, many native My Thinking
plant species are now We own cats
that live outside.
They help keep
During World War II, a mice out of our barn.
small snake whose native habi- That is like introducing
tat was the Solomon Islands, a species.
New Guinea [gi•nee], and
northern Australia was acci-
dentally brought to the island
of Guam. On Guam this tiny
brown tree snake has eliminat-
ed several species of native
lizards. It has destroyed most
of the songbirds on the island,
too. It is also threatening
native bats. So far, no known
means of destroying it have
been found. Although nothing was done intentionally,
this is a good example of what can happen when people
introduce species into a new habitat.
Is there anything that can be done to stop the mass The tiny brown tree snake
extinction happening today? has eliminated several
species of lizards.
Can Laws Have an Effect?
In the United States the
Endangered Species Act of 1973
makes it illegal to “kill, hunt, collect,
harass, harm, pursue, shoot, trap,
wound, or capture any endangered
species.” It prohibits buying and sell-
ing species that are endangered and
protects critical habitat. Large fines
and jail terms are given to those who
break the law.
[ 149 ]
The Convention on International Trade in Endangered
Species of Wild Fauna and Flora (CITES) is an interna-
tional treaty that protects endangered species worldwide.
Make Connections It also bans buying and selling endangered species.
by comparing my However, not all nations obey this law. Whales are still
experiences with what hunted in some nations. Tigers, rhinoceros, elephants, and
other unusual animals are still killed by
My Thinking poachers for their skins and ivory.
I think most
people follow anti-
litter laws, so I’m
sure antihunting and
antipoaching laws work
for the environment.
These pilot whales have been hunted in the Faroe Islands.
Restoration of Species
Animals that are in danger of extinction are protected
in the United States. In some instances they are restored
in captivity and then released in the wild. In 1986 there
were only 2 California condors left in the wild. These
magnificent birds were victims of DDT. In the past 14
Vo • cab • u • lar • y years, these birds have been bred and raised in captivity.
poachers (poh•chuhrz)— Today they are being released in small numbers into the
people who hunt or fish illegally wild again. The entire world population has reached 198.
[ 150 ]
Much is being done throughout
the world to educate people about
the dangers of extinction. Efforts
are being made to slow pollution,
reduce logging, and limit or ban
hunting. A worldwide effort is
being made to save animals and
plants. National parks, preserves,
and conservation land are being
saved to protect habitats. It is
hoped that the tales of the dodo
bird, passenger pigeon, and gold-
en toad will not be repeated.
Instead, stories of animals that
have been saved—the California
condor, the bison, and the giant The California condor
panda—will be more common.
Humans have caused this latest mass extinction, and
only humans can stop it. They can change how they treat
the planet Earth and all its living things.
by using the headings to question myself about
what I read.
The strategy says to use the headings to question
myself about what I read. “What Is Extinction?” It is
the total elimination of a species. “Modern Causes”:
The modern causes for extinction are habitat destruc-
tion, pollution, hunting, and introduced species.
[ 151 ]
Graphic organizers help us organize information. I think this article
can be organized by using a cause-and-effect chart. Here is how I
organized the information. I listed initial causes of a few events.
Then I listed what the effects were.
Going, Going, Gone
The Ordovician extinction was Widespread glaciation occurred;
caused by a sudden cooling of 20%–50% of all species became
Late Devonian extinction was Many fish and marine
caused by cooling, especially in invertebrates died. About 1/4 of
the seas. all species became extinct.
Permian extinction was caused by Half of all living things
either rapid warming or by Earth disappeared.
being struck by a large object.
Late Triassic extinction was
One third of all plants and
caused by volcanic eruptions and
Late Cretaceous extinction was
Fifteen percent of all species
caused by a comet hitting
(including dinosaurs) disappeared.
Current Holocene extinction is Nearly 1,000 species are
caused by people polluting and becoming extinct each year.
destroying natural habitats.
[ 152 ]
Writing for Comprehension
I used my graphic organizer to write a summary of the article.
Can you find the information in my summary that came from
my cause-and-effect chart?
A Summary of
Going, Going, Gone
It seems as if Earth is much the same every day, just changing with Here is how I developed
the seasons. In fact, Earth has experienced sudden and shattering my introductory para-
graph. It gives readers
changes. These changes have shaped our lives today. Scientists have
an idea of what they
identified 6 major extinctions and their results. are about to read.
The first extinction that we know about happened during the
Ordovician Period. About 440 million years ago, Earth’s surface
suddenly cooled. This change caused widespread glaciers to form,
even over tropical land. As a result, 20 to 50 percent of all the Body
I used information from
species on Earth became extinct.
The next extinction came during the Devonian Period, 360 million chart for each para-
years ago. The same kind of cooling seems to have occurred again. graph in the body of
This time, it killed about 1/4 of all species. That included many fish and my paper.
The third major extinction happened during the Permian Period. It
was about 250 million years ago. Earth either experienced a rapid
warming, or it was struck by a large object. Half of all living things dis-
The fourth extinction occurred during the Late Triassic Period.
Volcanic eruptions and the impact of asteroids probably caused this
extinction. One third of all plants and animals were destroyed, but
not the dinosaurs.
The fifth extinction dates to the Cretaceous Period. Scientists think
that a comet hit Central America. This impact set off changes that
killed 15 percent of all species. This time, the dinosaurs were victims,
You are living through the sixth extinction. We are now in the
Holocene Period. Unlike the other extinctions, this one is happening
slowly and quietly. It occurs daily as people pollute and destroy
natural habitats. We are losing about 1,000 species every year. I concluded my paper by
At last, we have an extinction we can control, but will we? asking the reader for a
[ 153 ]
Scientific classification groups all known living things into a class,
family, genus, and species. The names for all of these categories
come from Greek and Latin words.
For example, humans belong to the class of mammals. Mammal
comes from the Latin word mamma, meaning “breast,” because
mammals are fed from their mother’s breast.
In “Going, Going, Gone,” you learned that several large felines, or
cats, are endangered. Felis is the genus name for cats, both domes-
ticated and wild. Cats are also mammals, but they are of the
Match the class, family, or genus name from the list with the
Greek and Latin words and meanings. Write your answers on
a separate sheet of paper.
a. Reptila b. Amphibia c. Arachnida
d. Muridae e. Canis
1. The family of rats and mice is derived from the Latin
word mus, meaning “mouse.”
2. The class that includes frogs is derived from the Greek
word amphi, meaning “both,” and bios, meaning
3. The class of alligators is derived from the Latin word
reptilis, meaning “creeping.”
4. The genus of dogs is derived from the Latin word
caninus, meaning “conelike tooth.”
5. This class is derived from the Latin word arachnida,
[ 154 ]
Practice reading this poem about the endangered chimpanzee
with a partner. Alternate stanzas with your partner. When you
are ready, perform the poem for your class.
This poem encourages people to battle against
animal extinction. Read it as a radio announcer
might. Use your voice to convince people to
Won’t You Help, Please?
The habitat of the chimpanzee
Is disappearing too rapidly.
Deforestation is the reason
For increased vulnerability.
Foreign hardwood logging companies
Make it easy to cut down the trees—
Leaving the chimp without a place
To hide, to hunt, or to just run free.
What about the innocent babies?
Sold to the circus so that maybe
We can see something entertaining.
A laugh is not worth a life, you see.
It’s disease, shock, and malnutrition
That have put chimps in this position.
The ones that survive are mistreated.
Giving chimps help should be our mission.
Jane Goodall insisted we protect
The chimpanzee from callous neglect.
She studied them so that you and I
Would always care and never forget.
[ 155 ]