Adaptations

Adaptations
A Science A–Z Life Series
Word Count: 1,648

Written by Ron Fridell

Visit www.sciencea-z.com www.sciencea-z.com

 Key elements Used in This Book
The Big Idea: Plants and animals, including humans, have to adapt

Adaptations
in response to changes in the environment. These changes can range
from global to microscopic, and may include changes in the climate,
the population of other species sharing the same habitat, and the
availability of essential resources for survival. Physical adaptations are
natural occurrences, not deliberate choices. Behavioral adaptations are
usually responses to environmental conditions, and are not momentary
decisions made by individuals. Some adaptations turn out to be
successful, and some do not. Only those organisms with successful
adaptations survive and pass on their genes to future generations.
Many different adaptations to a species are often successful, which
has led to incredible diversity in nature.
Key words: adapt, adaptation, animals, behavior, birds, blowhole, cell,
characteristics, climate, Darwin, drip tip, environment, evolution, extinct,
gene, generation, habitat, humans, inherited, instinct, mutation, naturalist,
organism, physical, plants, predator, rainforest, reflex, scientists, species,
survival of the fittest, survive

Key comprehension skill: Main idea and details

Other suitable comprehension skills: Classify information; identify facts;
compare and contrast; elements of a genre

Key reading strategy: Using a glossary and bold-faced words

Other suitable reading strategies: Using a table of contents and headings; ask
and answer questions; connect to prior knowledge; summarize; visualize

Photo Credits:
Front cover (top left, bottom left, bottom right), pages 3, 5 (top left, bottom right), 6, 9, 10, 13, 15,
16 (left), 17 (bottom), 19 (left), 22 (both bottom): © Jupiterimages Corporation; front cover (top right):
© iStockphoto.com/Prill Mediendesign & Fotografie; back cover, page 8 (top): © iStockphoto.com/
Håkan Karlsson; title page, page 20 (bottom): © Behavioural Ecology Research Group/
University of Oxford; page 5 (top right): © iStockphoto.com/Sam Chadwick; page 5 (bottom left):
© iStockphoto.com/James Stoddard; page 8 (bottom): image courtesy of UC Museum of Palentology/
www.ucmp.berkeley.edu; page 11 (top): © iStockphoto.com/Mikael Damkier; page 11
(bottom and inset): David Gates/© Learning A–Z; page 12: Sheryl Shetler/© Learning A–Z;
page 14 (top): © iStockphoto.com/Carl Jani; page 14 (bottom): © iStockphoto.com/Marc C. Johnson;
page 16 (right): © Stephen Dalton/Photo Researchers, Inc.; page 17 (top): © iStockphoto.com/
Mark Weiss; page 18: © iStockphoto.com/Iurii Konoval; page 19 (right): © Hemera Technologies/
Jupiterimages Corporation; page 22 (top left): © iStockphoto.com/Jelani Memory; page 22 (top right):
© iStockphoto.com/Rena Schild

Illustration Credits:
Pages 4, 20: Stephen Marchesi/© Learning A–Z; page 7: Cende Hill/© Learning A–Z
Written by Ron Fridell

Adaptations
© Learning A–Z
Written by Ron Fridell
www.sciencea-z.com
All rights reserved.

www.sciencea-z.com
Cactus spines are an adaptation to keep animals from eating
the plant.

Table of Contents

Introduction........................................................ 4
Introduction
Survival of the Fittest.......................................... 6
Afternoon sunlight shines through the .
Plant Adaptation............................................... 10 trees in a park. A small bird called a warbler
sings on a tree branch. Suddenly, he stops
Animal Physical Adaptation........................... 13
singing. He catches an insect flying by. The
Behavioral Adaptations.................................... 16 insect can’t get away, and the warbler eats his
snack. Down on the ground, a red cardinal
Human Adaptations......................................... 19 cracks open seeds with his bill. A rat-tat-tat-tat
sound rings out as a woodpecker makes a hole
Adaptations Everywhere................................. 22
in a tree. Hunting grubs, she drills through .
Glossary............................................................. 23 the bark. On a pond nearby, some ducks float
along. Their heads dip into the water. When
they come up, their bills drip with water.
3 4
 These birds are all looking for a meal. But Survival of the Fittest
because their food is different, their beaks
All living things, or organisms, must adapt
have different shapes. The warbler’s beak is
to changes in their environment to survive. If
pointed like tweezers. The cardinal’s beak .
they adapt, their babies will survive. Living
is short and hard like a nutcracker. The
things that do not adapt usually die out. When
woodpecker’s beak is hard and pointy. Duck .
plants and animals adapt as a way to survive it
bills strain plants and fish out of the water.
is known as “survival of the fittest.” The first
Over many thousands of years, these birds’ person to write about this idea was Charles
beaks adapted to help them gather the food Darwin, a British naturalist. He wrote about it
they need. All plant and animal species have 150 years ago.
adaptations, or changes that help them
How do adaptations happen? Within a
survive in their habitat. How do adaptations
species, lots of individuals are born with slight
help each living thing? Let’s find out.
differences. These differences may change the
way an animal or
plant grows .
and what it can
do. Sometimes
one of those
differences can
help that living
thing adapt to .
a change in the
environment.

Each bird’s beak is adapted to its habitat and food source. Charles Darwin

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 If the change helps a living thing survive, that
living thing will pass on the change to the next
generation. The change becomes an adaptation.

For instance, millions of years ago, all whales

had teeth and breathed out of holes at the end .
of their snout. Over many generations, some
Blowhole
whales developed a breathing hole further up .
their head. These whales could breathe more .
easily in deep water. They could rise to the . The location of a modern
whale’s blowhole makes
water’s surface and take a breath without . it easier to breathe.
sticking their snouts above the water. As .
whales began to spend more time far out in the Today, the whale has a hole on top of its
ocean, away from shore, the whales with higher head for a nose. It is called a blowhole. The
breathing holes survived better. Their babies . blowhole makes it easier for the whale to
also had breathing holes high on their heads. breathe. When it needs to breathe, a whale
keeps the blowhole above water. It takes a
The Whale’s Nose
breath through its blowhole. Then the whale
dives back down into the ocean.

Breathing Hole
Oldest: A Pakicetus Whale

Old: A Rodhocetus Whale

This skull is from a very ancient whale. Its breathing hole was
Modern: A Grey Whale today further forward than a modern whale’s.

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 What happens to plants and animals that cannot
adapt to changes in their environments? They
become extinct, which means they die out and
none are left on Earth. Thousands of living things
died out before humans existed. We learn about
these extinct plants and animals from fossils.

Desert plants are spaced wide apart.

Plant Adaptations

Plants have to adapt to their environment

to survive and make new plants. For example, .
they must find a way to get enough water .
and sunlight to make their own food. Let’s
Maybe dinosaurs did not adapt to changes in their environment. look at how desert plants and rainforest .
plants had to adapt to get the water and
Dinosaurs became extinct 65 million
sunlight they need.
years ago, but no one can be sure why. Some
scientists say a giant meteor may have hit There is not much water in the desert. Most
Earth. It may have sent tons of dust into the deserts get less than 25 centimeters (10 inches)
air that blocked the sun and killed their food. of rain every year. But each plant must get
Others think dinosaurs died out because they some water. Plants in the desert grow apart
could not adapt quickly enough when Earth’s from each other so they do not have to share
climate changed. the small amount of water when it rains.
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 Rainforests get about In the rainforest,
200 centimeters (80 inches) trees grow tall and
of rain every year. Some spread their leaves.
plants have adapted the This forms a thick
shape of their leaves so layer at the top of the
rainwater rolls off easily. trunk where leaves
Their leaves have sharp can get sunlight. .
points called drip tips But this makes it .
that make the water run . very shady for .
to the tips of the leaves. . plants underneath.
Drip tips help plants to
Then the water drops to . shed water quickly. Vines called lianas
the ground. If the plant . have adapted to get
received too much water, it would die. the sunlight they
Though there is not much water in the need. Lianas climb .
desert, there is plenty of sunlight. The desert the tallest trees to
haworthia plant has adapted to protect itself reach the sunlight
from too much light and heat. It grows mostly above them.
This vine is climbing a tree in the
underground where . rainforest to reach sunlight.

it is cooler. But the .

plant must get some .
Plants cannot see or hear, but they can still sense
sunlight to make . changes in their environment. Chemicals in the
food. So the tips . plant cells react to the heat, light, moisture, and
of its leaves poke . temperature around the plant. All these things
can make it easy or hard for a plant to do well.
through the soil. They . A plant grows quickly or slowly because of
have clear “windows” . signals from the chemicals.
“Windows” in the haworthia’s
to let in light. leaves let light in.
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 Animal Physical Adaptations

Plants make their own food, but animals

have to hunt for their food. Over millions of
years, some kinds of animals have changed .
so that they can find food more easily. Other These camels are traveling in a
caravan across the desert sand.
changes protect these animals from other
animals that hunt them.
Before we had vehicles that could travel over sand,
The giraffe’s neck is a good example. people used camels to get around. With their
Giraffes born with longer necks could reach transparent eyelids and long legs, they were well
higher into trees to get more food than giraffes adapted for traveling in the desert. Camels carried
goods across desert sands in long lines called
with shorter necks. They could also see caravans. This is why the camel’s nickname is the
enemies coming. The giraffes with long necks “ship of the desert.”
were more likely to survive and have babies
than the giraffes with . Another example of an animal with a
shorter necks. Soon . physical adaptation is the camel. Camels .
more giraffes were . live in deserts where there are many
born with long necks. sandstorms. This makes it hard to see. .
But camels have an extra set of eyelids that
The giraffe’s neck .
are see-through. These
is a change to its .
special eyelids protect
body, or a physical .
the camels’ eyes from
adaptation. Many .
the stinging sands .
animals, like whales, .
so they can keep
have physical .
Giraffes use their long moving, find food,
adaptations too. necks to reach food.
and avoid predators. A camel eye has a clear eyelid.
13 14
 Australia’s koala bears are adapted to their Behavioral Adaptations
environment. They spend a lot of time in
Many animals have adapted their behavior
eucalyptus trees, eating the leaves. To help
as well as their body. Behavior is the way an
them climb trees, their toes have big gaps
animal acts and reacts to its environment. .
between them. This helps them grab branches.
A basic inherited behavior is a reflex, such
The camels’ eyelids and the koala bears’ toes as a frog jumping when it is touched. A reflex .
are physical adaptations. These adaptations are is something an animal does without thinking
inherited from their parents. about it.

A frog’s jump is a reflex.

Instinct is another kind of inherited

behavior. A sea turtle digs a hole in the sand
to lay its eggs because of instinct. Birds fly
south in the winter because of instinct. The
animals act the same way each time the same
thing happens to them.

Animals learn some behaviors by being

taught. For example, you can train a dog to
obey commands. Reading is a behavior you
learn from practicing at home and school.
Koalas have big gaps between their toes so that they can
grab branches.

15 16
 Some scientists wanted to find out if birds
know songs when they are born or if they
learn them later from their parents.

Male peacocks They studied the songs of birds that grew

display their
tails to attract up in a group with parents. These birds’ .
females.
songs sounded just like their parents’ songs.
The scientists
Some behaviors help animals attract a mate.
listened to the
For example, a male peacock spreads out its
songs of birds
colorful tail feathers to get the attention of a
that lived on
female peacock. The pufferfish inflates its body
their own.
to look bigger to its predators.
These birds
Some behaviors keep animals safe from . knew how to
other animals that hunt them. Many animals, sing, but their .
such as flamingoes and zebras, live and move. songs were
Birds sing simple songs by instinct, but
in large groups. Rabbits live in underground very simple. they learn complex songs from others.
burrows so they can hide from their enemies.
The scientists decided that birds inherit the
Scientists are ability and urge to sing. But young birds learn
puzzled by some complex songs by listening to older birds.
behavioral adaptations.
Many behavioral adaptations are like bird
They don’t know if the
songs. When animals are born, they know
behavior is inherited .
part of a behavior. Then they learn other .
at birth or was learned
parts from their parents and other animals.
A pufferfish inflates its body to later from parents.
look bigger to its predators.

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 Human Adaptations

People adapt too. For example, we keep .

cool in hot weather by sweating. When it is .
hot, the sweat evaporates and cools our skin. .
In cold weather, we shiver, which makes
enough heat to warm us up for a short time.

The adaptation of intelligence helped us create tools and hunt.

Early humans learned to make tools

because they needed to survive in a
dangerous environment. The animals that
lived around them used strong jaws and .
sharp teeth to survive. Humans used their
Sweating is an adaptation to help
stay cool. intelligence to invent tools. This helped .
them hunt animals and survive.

Only mammals sweat.

Primates sweat all This crow bent a wire
over their bodies. to turn it into a hook.
Dogs and cats only That’s the first evidence
sweat on their feet. Shivering is an adaptation of birds making tools!
to help stay warm.

19 20
 Many Words for the Same Thing Adaptations Everywhere

House – English sp ti – Greek Think about adaptation. Consider physical

and behavioral adaptations. What do you know
Haus – German Casa – Spanish about inherited and learned adaptations?
Rumah – Indonesian hus – Swedish Look around your own environment. What
Bahay – Tagalog
adaptations do you see? How do the adaptations
– Chinese
help living things get everything they need?

One of the most important human

adaptations is our use of language to
communicate. The songs of birds and the .
cries of monkeys are simple signals. But
humans have developed complex systems .
of sounds and symbols to communicate with
each other. There are over 6,900 languages
spoken in the world today.

Like all animals, humans have adapted.

But while animals inherit most of their
adaptations, we mostly use learned behaviors
to get what we need. To keep warm, we wear
clothing, build fires, make electricity, and live
in homes. To get food, we grow fruits and
vegetables, and raise animals. We learn to
speak, read, and write languages. We use
bikes, cars, and airplanes to get around. How have these organisms adapted to their environments?

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 Glossary habitat the natural conditions and
adapt to change parts of the body environment in which a .
and behavior to match changes . plant or animal lives (p. 5)
in the environment (p. 6) inherited passed on from parent to
adaptation a specific change to a physical child (p. 15)
feature or a behavior common . instinct inherited behavior that leads
to a species which helps the . an animal to act certain ways .
species survive (p. 5) in certain situations (p. 16)
behavior a way of reacting to a certain organism a living thing (p. 6)
set of circumstances (p. 16)
reflex an automatic response (p. 16)
blowhole a hole at the top of a whale
or dolphin’s head, through . species a group of related organisms
which it breathes (p. 8) with characteristics that
distinguish it from other .
environment all of the conditions affecting groups of organisms (p. 5)
an organism in one area,
including the plants, animals, . survival of a theory explaining that the
water, soil, weather, landforms, the fittest organisms best suited to live
and air (p. 5) in a particular environment are
those most likely to survive .
extinct no longer in existence (p. 9) (p. 5)

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