33960_First Childrens Encyclopedia

Water, water Your amazing body
Your body is mostly
water – it makes up Curiosity quiz
about two-thirds of
Take a look at the
your weight. pages in this section
and see if you can
find these pictures.

The ingredients

Your body is made of just
a few simple chemicals,
plus water.

Carbon is what diamonds
and coal are made of.
A fifth of you is carbon.

Iron makes your blood
red. You have enough to
make one small iron nail.

Robot Phosphorus is in the
tips of matches, as well
No substitute as your bones and teeth.
The human body is too
complicated for robots to Sodium and chlorine
copy. Robots can copy the make salt. Blood is one-
way we walk, but they third as salty as sea water.
can’t think or feel like we do.
Potassium is used in
some types of soap. It’s
also in your body fluids.

Nitrogen is important in
muscles. It’s also the main
ingredient in air.

Chimps have Compared to chimps, Being human
hands like ours. our bodies look almost
Although we look different from
hairless.
animals, our bodies are similar

Chimpanzee on the inside. Our closest

animal relatives are

chimpanzees. 99

Anatomy.

Human body

What makes you you?

All human bodies work the same way, but everyone
is different. Nobody looks, sounds, or thinks exactly
like you. You’re different because of the way your
genes and experience shape you as you grow up.

Fair skin

Green eyes

Curly hair

Black hair

Unique

The shape of your face,

the colour of your hair,

and many other things

Freckles make you unique –
different from

everyone else.
100

How many genes are there in each cell in the human body?

What makes you you?

In the genes

Genes are instructions that
build your body and tell it

how to work. Your genes
control many of the things

that make you unique,
like the colour of
your eyes or how
tall you’ll be.

There’s e This girl has a gene that allows Hands on
her to roll up her tongue. The
DNA boy doesn’t have the gene, Look in a
Your genes so he can’t do it. mirror and see if you
are stored in can roll your tongue. Don’t
a chemical called DNA inside you to cheat by squeezing it with
DNA, which looks like a un a your lips. Test your
twisted ladder with four stretc
different types of rung. family to see who
The rungs make up a nough
four-letter alphabet that h to the S has the gene.
spells out your genes,
like letters in a book. DNA can nd back 400 times.
split and
copy itself.

In the family Learning to ride
Your genes came from your parents. a bike changes your
Half come from your mother and brain and your
half come from your father. If
you look like your parents, it’s body.
because you share the same genes.
Changing body
Genes don’t control
everything – experience

also shapes you.
If you exercise a
lot, for instance,
your body gets
stronger.

101
About 30,000 specific genes.

Human body

Building blocks

Every part of your body is made of
tiny building blocks called cells, which
fit together like bricks in a wall. Cells
are so small that hundreds could fit
on the point of a pin.

The nucleus DNA is
controls the rest stored in
of the cell. the cell
nucleus.
The inside of NA
a cell is packed D The skin on your
with a kind of fingertips is made
living jelly called of lots of small
cytoplasm. ridges.

Inside a cell

In the middle of a cell
is its control centre – the
nucleus. The nucleus sends
instructions to the rest of
the cell, telling the cell
what chemicals to make.

Before a cell divides,
the nucleus splits to
make two nuclei.

The outer skin, or Tiny generators
membrane, stops provide cells with
things leaking out. power.

102 Making new cells The new cells pull apart
A cell makes new cells by dividing. and separate, but they
The two new cells are half the size,
but they soon grow back. Millions of usually stay close
your cells die every second, but millions neighbours.

of others divide to replace them.

How many cells are there in the human body?

How big are cells? Building blocks

Cells are too small to see with the More than 2000 dead skin cells f
naked eye, but scientists can ell off you while you read this sentence.
photograph them through
powerful microscopes.
The cells on your skin
are about a hundredth
of a millimetre wide.

A microscope can The cells on
zoom in to see the the surface of
tiny, flaky cells on the your skin are tough
ridges of your fingerprint. and flat. They overlap to
form a layer of armour that
protects the softer cells below.

Fat cells are Many blood cells Nerve cells are Bone cells make Cells make tissue
bubble shaped. are red. They thin and wiry. your bones hard. Your body contains
They store fat carry oxygen They live in tiny hundreds of different
under your skin. They carry holes in bones. types of cells that do
around the body. electrical signals. different jobs. Cells of
the same type usually
About 100 trillion. group together to form
tissue. Fat, muscle,
bone, and nerves are
types of tissue. Blood
is a liquid tissue.

103

Human body Systems

Organizing Organs and
the body tissues work in
teams to carry out
Your cells and tissues are major tasks, like
organized into larger body transporting blood
parts called organs. In turn, or processing food.
your organs work together These teams are
to form body systems. called systems.

Kidney The heart is the
largest organ in the
Heart blood system. It
pumps blood around
Brain the body.

Organs The tubes that carry
blood away from the
An organ is a body part that heart are called
does a specific job. Your heart’s arteries (shown
job, for instance is to pump in red).
blood. Kidneys clean blood.
The tubes that
carry blood back to
the heart are called
veins (shown in
blue).

Organ transplant Heart and blood
If a vital organ stops working, doctors Your heart, blood, and
may replace it with an organ from another blood vessels make up
the blood system. It
person. This is called a transplant. transports vital supplies
around your body.
104
Which body system makes your stomach rumble?

Muscles Muscles change Organizing the body
Your muscle system is made the position of your Other systems
of tissues that move parts skeleton by pulling
of your body by pulling different bones. Some of your other
on them or squeezing important systems
them. Your biggest are shown in this list.
muscles all pull
on bones. Breathing system: the
main organs are your
Your fingers lungs, which take in air.
are moved by
muscles in Hormone system: this
your arm. uses powerful chemicals to
control your body and mood.
The most powerful
muscles are Skin, hair, and nails:
in your legs. these form your body’s
protective covering.
Skeleton
Immune system: this
Bones and seeks and destroys germs
that get into your body.
joints make
Urinary system: this
up the skeletal cleans blood and gets
rid of waste chemicals.
system, an
Reproductive system:
inner frame these are the organs that
make babies.
that supports
Digestive system
the body. Your digestive
A quarter of organs break
down food to
Nerves your bones are provide your
in your feet. body with energy
and raw materials.
Your nervous system carries
Your mouth is the first
electrical signals around part of the digestive

your body. You need system.

Signals shoot this system to see, A long, twisting tube
along nerves to makes up your
muscles, hear, think, intestines, where
telling them digested food is
when to pull. and react.
absorbed.
Senses, such as Your brain is the
touch, rely on nervous system’s 105
nerve cells that control centre.
send signals to
your brain.

The digestive system.

Human body Skull
Ribcage
Bones and muscles

You would be like a lump of jelly without
your skeleton – a frame of bones
that holds you up and protects
your internal organs.

Bending backbone Backbone

Your backbone The wrist is
made up of
contains 24 small eight small
bones.
bones called
Cranium
vertebrae. They

move almost

The vertebrae in every time
your back allow you you do.
to twist and bend.

Head case The hip is a
The bones that make up your ball and socket
skull join after you are born. joint, allowing the
legs to move around.
The skull has two parts –
the lower jaw and cranium.

Only your jaw can move.

Bone marrow Lower jaw
supplies your
body with red The honeycomb
blood cells. structure of some
bone makes it
weigh less than
if it were solid.

Both the knee and elbow are hinged
joints that only move in one direction.

Brilliant bone Snake ribcages Ribcage
Bones have a can run almost A ribcage has
clever structure that the entire long, curved bones
makes them light but length of that protect vital
strong. They can heal their bodies. organs such as the
themselves if broken. heart and lungs.

106 How many bones does an adult human have?

Bones and muscles

Bending bits Muscle magic

Different kinds of joints Muscles are rubbery,
all over your body keep
you moving. stretchy straps. The pectoralis Biceps and
You can control muscle moves triceps bend
Thumbs have joints that some of your muscles, your arm at the and straighten
allow them to rotate, shoulder. your arm.
which fingers cannot do.
like the muscles in your
Ankles contain different
joints for up-and-down arms and legs. Others,
and side-to-side movement.
such as your heart and
Wrists have a joint that
allows them to turn but bladder, operate without
not go all the way round.
you having to think

about it.

Neck bones feature a
pivot joint that allows
your head to turn.

Making faces The tibialis
Muscles in your face are muscle bends
attached to skin as well as your foot.
bone. They allow you to
make all kinds of expressions Pulling pairs
to show how you are feeling. Muscles can pull
but they can’t
push. They work in
pairs that pull in
opposite directions.

The biceps
contract to pull
the forearm up.

The triceps relax
and stretch when
the biceps contract.

There are 206 bones in an adult skeleton. 107

Human body

You use
your brain

Brain and sensestothink.

Your brain is the part of your body

that makes you think, feel, and

remember. It makes sure that the
parts...
rest of you works properly.
Different
Your brain

Your brain is hidden
inside your head. It

looks a little bit like a

soft, wrinkly lump

of greyish-pink

Your hard, bony skull protects blancmange,
your brain from damage.
A bundle of or jelly.
nerves runs
down your Nerves
back, inside
your backbone. Your brain is linked to your

body by fibres called nerves.

Nerves carry messages from

your body to your brain,

and back again. Your brain weighs
about the same
as 12 apples.

If you prick your Reflex actions
finger, your brain
makes you feel pain. If you accidentally

prick your finger on a

rose thorn, your brain

quickly makes you

pull your hand away.

This fast reaction is

called a reflex action.
108

Do clever people have bigger brains?

Brain and senses

Your senses Your eyes see Eyes and seeing
the pictures, Your eyes have special nerves
You know what is happening then your that pick up light. They send
around you by seeing, brain tells messages to your brain, telling
hearing, smelling, tasting, you what you what you are looking at.
they are.

and touching things. These Your ears pick
are called your senses. up loud and
soft sounds.
do different jobs.
Ears and hearing
Your ears catch sounds and send

them deep inside your head.
Nerves send messages about
the sounds to your brain.

Nose and smelling
Nerves inside your nose
tell you what you are

smelling. Some things,
such as this rose,
smell nice. Other
things smell terrible!

Brown Grapes Spaghetti Tongue and tasting
sugar You taste with your tongue.

It is covered with tiny 109
bumps, called taste buds,

which pick up tastes
from your food.

Skin and touch
Nerves in your skin
tell you if things feel
hard, soft, hot, or cold.
They also warn you of
danger by making
you feel pain.

Can you tell what you are
touching, without looking?

No. Everyone’s brain is about the same size.

Human body This flap shuts
when you eat
Breathing so food can’t
go down your
We have to breathe all the windpipe.
time in order to supply our
bodies with oxygen and You breathe in
to get rid of carbon
dioxide. We use our through your The air travels down
lungs to do this. nose or mouth.
your windpipe.
Prepare the air
Each lung is a
Before the air reaches your lungs it spongy maze of
travels through your mouth and tunnels.
nose and then goes down your
windpipe. It gets warm and
damp on its journey.

When you breathe
in, your lungs stretch
out and take in lots
of air.

In and out The aditarpahmrpaogmlinies.
Your ribs and diaphragm help you to like

When you breathe

breathe. Your lungs fill with air when out your lungs The muscle under your
you raise your ribcage, then empty out squash down forcing lungs is called the
when you lower it. A muscle called the all the air out. diaphragm.It moves

diaphragm helps you do this. up and down as you
breathe.

110
How many breaths do you take in a day?

A helping hand Breathing
Some newborn babies
have trouble breathing. No lungs
They are put into an
enclosed cradle called Not every animal has
an incubator. Extra lungs. There are other
oxygen is pumped into ways animals breathe.
the incubator for them.

The view from the Windpipe
bottom of your Air from your mouth
windpipe. and nose enters your
windpipe, which
goes down your Frogs can absorb oxygen
throat into your through their skin – even
chest. Then it splits underwater.
into two passages –
one for each lung.

The alveoli are
surrounded by tiny
blood capillaries to
take the oxygen round
the body.

Insects such as caterpillars
breathe through body
openings called spiracles.

Air sacs Many sea creatures such as
Your lungs are full of tunnels sharks breathe through gills.
ending in tiny air sacs called
alveoli. Here, oxygen from the 111
air passes into your blood. Your
blood carries oxygen around
every part of your body.

About 23,000.

Human body

All about skin

Skin covers your whole body. It protects
you from germs, water, and sunshine,
and helps keep your body at the
right temperature.

The skin on Two layers
your eyelids
is the thinnest Your skin has two main layers.
on your body. The top one – the one you can see –

is called the epidermis.
Underneath is the
dermis, where there
are nerves and
blood vessels.

is a sort of s tretchy overcoat. There are flat cells on Waterproof seal
Skin the surface of your Skin stops water getting into your
Heavy load skin. These are made body when you have a shower or
Skin is the from a tough material go for a swim. It also stops fluids
heaviest single called keratin. When the escaping from inside you.
part of your cells die, they dry out and
body. It can flake off. Magnified skin flakes
weigh as much
as a bag of Skin cells lower down
shopping. replace the dead ones
that flake off.
112
House dust The thickest skin on
Dust is mostly
made of dead
skin. Dust mites
feed on this skin.
They live in
beds, pillows,
and carpets.

Dust mites aren’t
really this big! They’re
so small you can’t see
them.

How many dead-skin flakes fall off every day?

All about skin

Sweat

Sweat pore

Sweat gland

If you uncurled a
sweat gland, it could
be over a metre
(3 ft) long.

Skin colour
The colour of your skin is affected by a
substance called melanin. The more melanin
you have, the darker you will be. When you
are outside in the sun, your body produces
extra melanin to protect your skin. This melanin
makes your skin darker and you get a suntan.

your body is on the soles of y
our feet.

Soggy skin Cooling down
When you soak in water for a long
time, the top layer of your skin gets When sweat dries on your
waterlogged and wrinkly. skin, it helps to cool you

down. Sweat comes from
coiled tubes under the
surface. It gets out
through tiny holes

called pores.

About ten million. 113

114 Body defences Poison tears Human body
Which is your largest defensive organ? Germs that land
Although you can’t see them, germs on your eyes are
are always landing on your body washed away by
and trying to get inside it. Your tears, which come
body has lots of clever ways from glands above
of keeping them out. your eyes. Tears
contain the chemical
Sticky business Earwax flows You ma lysozyme, which kills ints) of saliva a da
Germs get into your lungs slowly out of bacteria by making
when you breathe in. They your ears all the
time, flushing out them burst open.
dirt and germs.
ke about 1 litre (2 p
get trapped in a sticky liquid
Saved by spit
called mucus, which lines your The liquid in your mouth
is called saliva. As well
airways. Tiny beating hairs as helping you digest food,
saliva protects your mouth,
continually push the mucus up tongue, and teeth from
attack by bacteria.
to your throat to be swallowed.

y.

Your skin. Become Acid attack
an expert Glands inside
your stomach
110-111 Breathing make acid, which
116-117 Eating kills germs you’ve
and digestion swallowed. Your
digestive system then
Slimy guts breaks down the germs
The inside of your intestines are along with your food.
covered with slimy mucus, which stops
germs from getting into your blood. Yuk!
Your large intestine also contains The feeling of disgust protects you from
millions of “friendly” bacteria, which germs. Anything that smells revolting or
prevent other germs from growing. looks horrible is probably full of germs.
Disgust stops you from touching it.
Body defences

115

Human body

Why does your stomach rumble?
Eating and digestion

Your body needs food to keep it working. Teeth
But before it can use the food, it breaks Tongue
it into tiny pieces, which seep into your

blood. This is called digestion.

Your food Mouth

travels In your mouth,

your teeth chop up

through and chew your food. Your spit helps

to break food down and makes it easy

to swallow. When you swallow,
your
This photograph of This tube diagram is not your food goes down a tube
part of the stomach the same shape as the into
lining was taken tubes inside your body. bodyin...yoyuorutrhsrtooamtaacnhd.
through a microscope.
Stomach

Your stomach is like a

stretchy bag that fills with Become
food. Inside, your food is an expert
churned up and mixed with
stomach juices. They break 222-223 All
your food down into a thick living things
soup-like mixture. 234-235 What

is energy?

Intestine Stomach Intestines

Because of air mixed up with your food. ...along a series Your small and Next, your food goes
large intestines are into long tubes called
coiled up inside your intestines. It seeps
your abdomen. through the walls of
the intestines into your

blood. Your blood
takes the nutrients
(goodness) in the food
around your body.

Your mouth, Small intestine
This intestine is called
stomach, and A meal takes one to your “small” intestine
three days to pass all because it is narrow. In
ointestines are the way through your fact, it is as long as a bus!
fcalled your digestive system.
pidigestive system. You get rid
A balanced dietpes and tubes.You need to eat a Large Small of waste water
intestine intestine and solid waste
when you go
mixture of foods to to the toilet. Eating and digestion

keep you strong and

healthy. This is called Vitamins in fruit and
a balanced diet. vegetables keep your
body working properly.

Carbohydrates such as Fibre in wholemeal Getting rid of waste
pasta, rice, and bread bread keeps your Any waste food travels
give you lots of energy. digestive system working. from your small intestine
into your large intestine.
117 Protein in milk helps Fat in butter and cheese It is stored there until you
you to grow and to gives you energy. Too go to the toilet and push it
repair your body. much fat is bad for you.
out as solid waste.

Human body The first cells
After 36 hours, the cell has
Making a baby divided and made an exact
copy of itself. These are the
You need a mother and a father to first two cells of a baby.
make a baby. The mother’s body does
most of the work, but the father also Eggs are the biggest cells in
has an important job – his sperm joins the human body. But they
with the mother’s egg and a new are still very small – ten
life begins... would fit across a pinhead.

Sperm are amazing
viewed under a microscope.
They look like tiny tadpoles. You
can see their tails wriggling as
they swim.

By the time the

Sperm race baby is born,

Millions of sperm swim towards the fertilized cell
the egg cell. Only one sperm can
join with the egg to make a new cell. will have become
100 trillion cells.

118
What is another name for the uterus?

Making a baby

Divide again The future you At three days
You don’t grow much in Each cell is unique to The cells have carried on
the first few days. The two you. Cells are full of dividing. There are now 16 cells
cells divide to make four, instructions about what and they are almost ready to
then eight, and so on. you will look like. plant themselves in the uterus.

Where it all happens The cells start dividing as
they move down the
The sperm fertilizes the egg in a tunnel, called a fallopian tube towards the
fallopian tube. The fertilized egg moves down uterus.

the tunnel towards the mother’s uterus. Millions of sperm
The journey takes about five days. from the father
travel up here
towards the egg.

This is the uterus. It This is the mother’s
is about the size of a ovary. It releases
pear and has one egg every month.
muscular walls.
Arriving in the uterus
The ball of cells plants 119
itself in the wall of the
uterus. In this warm,
dark place the baby
will spend the next
40 weeks growing
and developing.

The womb.

Human body

Amazing facts about YOU!

Skeleton Brain and nerves Breathing
and bones
Your brain is the Lungs take air into
Without a body’s control centre. your body so that
skeleton to hold Signals zoom to and life-giving oxygen can
you up, you’d from the brain enter your blood.
collapse on the along your nerves.
ground like a The inside of your
heap of jelly. Nerves carry signals lungs is as big as a
at up to 400 kph third of a tennis court.
Your smallest bone is the (250 mph).
stapes in your ear, which The fastest recorded
is smaller than a rice grain. Your brain is made of sneeze reached 167 kph
about 100 billion tiny (104 mph).
Weight for weight, bones cells called neurons.
are stronger than steel In one day you breathe in
or concrete. The left side of your brain enough air to fill 33,000
controls the right side of drink cans.
A baby has more than your body and vice versa.
300 bones but adults Skin, nails, and hair
The human eye can see a
have only 206. candle flame at night from The tough, protective
1.6 km (1 mile) away. surface of your body
Muscles and is almost entirely dead.
movement When you’re bored, the
pupils in your eyes get Every four years you
Muscles move your smaller. shed your own body
body by pulling bones. weight in dead skin.
You use hundreds of Heart and blood
them when you walk. You have about 5 million
Your heart pumps hairs, but only 100,000
Every hair in your body blood around your are on your head.
has a tiny muscle that body. It works nonstop
can pull it upright. without getting tired. The thickest
skin on your
Your strongest muscle is Your smallest blood body is on the
the masseter (jaw muscle), vessels are ten times soles of your
which closes your mouth. thinner than a hair. feet.

You use more muscles Your body contains
when you frown than enough blood vessels to
when you smile. circle the world twice.

120

Fighting disease Digestive Amazing facts
system Urinary system
Germs are always trying
to get inside you, but Digestion turns Urine gets rid of
your body fights back. food into simple chemicals that your
chemicals body doesn’t need.
Many germs are not that your
harmful, but some cause body can You will make enough
illness, and even death. make into urine in your lifetime
new cells or to fill 500 baths.
Bacteria are so small use for fuel.
that a thousand could Asparagus can turn your
fit on the head of a pin. urine green. Blackberries
can turn it red.

The world’s most The food you eat in Reproduction
common disease is a year weighs as
the common cold. much as a car. The reproductive organs
create new people from
Cancer happens when You make enough spit tiny specks of matter.
your own cells multiply in your lifetime to fill
out of control. two swimming pools.

When you recover from Your digestive glands The most babies born to one
an infectious disease, your start working as soon mother was 69. Most were
body becomes immune to it. as you smell or see food.
twins, triplets, or quads.

Your tongue senses five The first quintuplets
tastes: salty, sweet, sour, known to have survived
bitter, and savoury. infancy were born in 1934.

The smell of poo comes Growth
from a chemical called
skatole. As you grow you slowly
change into an adult,
Each hair on your head but it takes a long time!
grows for about 3 or 4
years and then falls out. The fastest-growing
A new one grows in part of a baby’s
its place. body is its head.

A girl is about three-
quarters of her adult
height at 7 years old.

A boy is about three-
quarters of his adult

height at 9 years old. 121

The living world

The living world

Our amazing world is filled with millions Dragonfly

of species, or types, of living thing. They

can be as big as an elephant or so

small you have to look through
Spider a microscope to see them.

Animals Micro-organisms
Micro-organisms are very
The animal kingdom is tiny – they are made up
made up of vertebrates of a single cell.
(animals with a backbone) This amoeba is
and invertebrates (animals magnified more
without a backbone). than 100 times.

Mammals, birds, Sunflower
reptiles, amphibians,
Coral reef and fish are vertebrates.

Deer

122 Which group of animals has the most members?

Snake Insects such as The living world
butterflies are
Plants invertebrates. Curiosity quiz

Plants cannot move Look through The
around like animals. To living world pages and
survive and grow, they see if you can identify
have to make their own the pictures below.
food. In turn, plants
provide food for many
animals and fungi.

Signs of life
Living things share some
characteristics. They all
need food and oxygen. They
also grow, reproduce, and
adapt to their environment.

Fungi Tree frog
Fungi (like toadstools,
mushrooms, and moulds)
are neither plants nor
animals, but they’re more
like plants than animals.

Fungi

Become
an expert

126-127 Types
of animals

148-149 How
plants work

Invertebrates – they make up 97 per cent of all animal species. 123

The living world

What is an animal?

A key definition of an animal, as opposed
to a plant, is that most animals can move
voluntarily. Animals must also eat other living

things to survive. Let’s take a look at some of
the things animals do.

Bald eagle Food is fuel
All animals have to find
Getting around and eat food to survive.
Carnivores are animals that
Many animals have eat meat. Herbivores eat
muscles, which allow mainly plants. Omnivores
them to move in a
variety of ways. are creatures that eat
both plants and meat.
Flying: birds fly by
flapping wings or gliding Squirrels eat seeds,
on currents of hot air. nuts, fruit, and fungi.

Swimming: animals What a nerve!
like fish swim by moving Animals have
their bodies and fins. nerves, which carry
information from their
Slithering: some snakes sense organs. Most
wriggle, others raise and animals have
flatten their bodies. brains to
monitor this
Walking and running: information. The
many animals walk and nerves also carry
run using legs. orders from the
brain to the organs
Reaching: sea anemones and muscles – such as
reach out their tentacles instructions to stay still,
to sting prey. attack, or run away!

124 How many species of animal are there on Earth?

Making babies What is an animal?
Most animals reproduce when a
female egg is fertilized by a male Do animals talk?
sperm. Some animals give birth to Many animals are able to
babies, while others lay eggs. communicate with each other.

Birds lay hard-shelled eggs, Pythons can go without
which hatch into chicks or food for months after
ducklings. one BIG meal!

Most beetles will send “messages” to other
beetles using special chemicals.

Baby birds have to break out Honey bees communicate constantly. They give
of the egg on their own. directions with a special dance.

Giraffes have seven vertebrae Monkeys scream
in their neck – the same as at each other to
most other mammals. They sound an alarm.
are just much longer.

Nobody knows the exact answer, but about 1.8 million have been identified. 125

The living world

Types of animals

There are so many different types, Lizard
or species, of animals that
scientists put them in groups Tortoise
so it’s easier to study them.
Mammals, birds, reptiles, Reptiles
amphibians, and fish are
vertebrates. Creepy-crawlies Most reptiles have dry,
are invertebrates. scaly skin. They mainly
live on land. Nearly all
reptiles lay eggs, but some
give birth to babies.

Mammals

Mammals usually have live
babies, which feed on their
mother’s milk when they’re
born. Mammals often have
fur on their bodies. Humans

Zebra

are mammals.

Wolf Deer fawn

126 Mouse Lion cub

What is the only mammal that can fly?

Birds Types of animals
Spineless creatures
All birds have wings,
and most (but not all) Animals without
can fly. They have backbones are called
feathers and a beak. invertebrates. There
Parrot Baby birds hatch are several types of
from eggs. invertebrates.

Ostriches can run fast Frog Insects, spiders, and
but can’t fly. Salamander crustaceans are part of
the largest animal group.
Amphibians
Snails and slugs are part
Amphibians live both of an invertebrate group
in water and on land. called gastropods.
They usually have
slimy skin. Baby Worms have long,
amphibians hatch soft bodies and no legs.
from jelly-like eggs. They like damp areas.

Jellyfish, starfish, and
sponges are invertebrates
that live in water.

Octopus and squid live
in the sea. They have
eight arms.

Butterfly

Fish Ladybird

Fish need to live Insects
in water. They There are more types of insect
breathe through on Earth than any other
gills, and most animal. Insects can live almost
are covered in anywhere. They have six legs
scales. Fish use and bodies with three sections.
their fins to move
through water. 127

The bat.

The living world

The world of mammals

Mammals include animals such as the
whale, the kangaroo, and you and me!
We all have fur, we are warm blooded,
and we feed new babies with our milk.

Gorilla Mammal babies
skeleton
Most mammal females give birth
to live babies, rather than laying
eggs. The baby grows inside
the mother’s
body until
it is born.

The skeleton Feeding babies

Mammals may All female mammals produce

look very different, milk from their bodies that

but stripped back they feed to their babies; this

to the bone we all feeding is called suckling.

have the basic bony The milk is rich

skeleton. Scientists and helps

call us vertebrates the babies

– animals with to grow.

a backbone.

Become
an expert

130-131 Marsupials
132-133 Water
mammals

Within the This baby
mammal group gorilla is a
there are many member of the
different families. primate family.

Baby
gorilla

128 How many mammal families are there?

The world of mammals

Hairy beasts Polar bears can live in chilly Arctic
regions because they are warm
All mammals are hairy – blooded and have thick fur.

some are much hairier than Warm blood
Mammals are warm blooded,
others – and most have which means they can warm up
and cool down their bodies to
hair, often keep their temperature level.
An elephant in the hot jungle
called fur, is the same temperature
as a polar bear
all over their in the snow.

bodies. They

are hairy to

Elephant keep them

warm.

This elephant may
not look hairy but
it does have hair
on its body.

Polar
bear

Getting around

Mammals are many
different shapes that
suit their lifestyles.

Cats: some mammals, The polar
such as the cat, have bear has thick fur
long legs to run with. all over its body.

Bats: the bat is the only The odd one out
mammal that can fly –
it has wings. It is usually true that

animals give birth to live

Dolphins: sea mammals babies, but there are a
have flippers and strong
tails to swim with. few species, including this

duck-billed platypus, that

Moles: the mole has lay eggs. Platypus eggs
feet like spades, which
are useful for burrowing. are soft and the size

of marbles. 129

There are about 4,500 different types of mammal in the world.

The living world

Marsupials More marsupials
A marsupial is a mammal
with a pocket Apart from a few that
called a pouch live in South America,
for carrying almost all marsupials
its babies in. come from Australasia.
They vary a lot in looks.
Koala
Koalas look like little bears. Dorian’s tree
They live in Australia and kangaroo: this small
are the only animal that eats kangaroo can climb trees.
eucalyptus leaves. They are so
hard to digest that koalas spend Numbat: this marsupial
19 hours of the day sleeping has the most teeth of any
to let their tummies settle. mammal. It has 52.

Rabbit-eared
bandicoot: is a
burrower with big ears.

Little devil

The Tasmanian devil is not much

bigger than a small dog but is very

aggressive. It is the biggest meat-

eating marsupial and has

When the baby koala such powerful jaws that
gets too big for the
pouch, it clings to its it can eat an entire
mother’s back instead.
animal – bones front legs are
and all! 's
oo
A kangar

Bouncing marsupials Become
Kangaroos cannot walk. an expert
Instead they have enormous
back legs that they use to 52-53 Australia
jump everywhere. They
can move very fast just 128-129 The world
by leaping. of mammals

130
Which are bigger, wallabies or kangaroos?

Opossums are Supermum! Marsupials
very good Opossums live in the
tree climbers. Americas. Unusually for This joey
marsupials, the mother is definitely
has no pouch. Instead big enough
her babies cling to her. to climb out
Sometimes one mother of its pouch.
can have up to 20
babies at one time! 131

In the pouch

Most marsupials have
pouches. When the babies are
born, they are as small as beans and wriggle
straight into the pouch. They do most of their
growing there, instead of in their mother’s tummy.

Little joey
Kangaroo and wallaby babies
are commonly known as joeys.
They spend several months in the
mother’s pouch, and even when
they are big enough to walk, they
sometimes jump back in for safety.

not used when they bounce

Their huge
tails help
to balance
them when
they run.

Kangaroos look like wallabies, but they are bigger.

The living world

Water mammals

Not all mammals live on land – some live in
water. Unlike fish, however, water mammals
have to go to the surface to breathe.

Seals

Seals, which include sea lions
and walruses, have flippers
instead of arms and legs,
which make them very good
at swimming but not good
at walking.

Sea lions can walk Underwater lives
more easily than Seals spend most of their
other seals because lives in water, but return
their flippers are to land to have babies.
able to move in They have a thick layer
several directions. of fat, called blubber,
which keeps them warm.
Sea lion

132 Seals are
often very
playful in
the water.

What noise do seals make?

Water mammals

Otters

Otters are small mammals that have
webbed feet to help them swim. The
river otter lives along river banks and
spends its day swimming to catch food.

Sea cows Otters of the sea
Manatees are often called The sea otter is the smallest sea mammal.
sea cows because they are It has luxurious, thick fur that keeps it very
so big and they “graze”, warm. It rarely comes to land, and even sleeps
like cows, on river-bed in the water. When it nods off, it wraps itself
plants. They spend all their up in kelp plants to stop it from drifting away!
lives underwater, and
even give birth there. Walruses use their noses,
like pigs, to root around
Walruses
the sea floor for food,
Walruses are such as crabs or
huge sea mammals that have sea urchins.
massive, blubbery bodies and very
wrinkly skin. They heave themselves
out of the water to rest and breed.

In the pink Walrus
Walruses are normally greyish-brown
in colour. But when they sunbathe, they
blush pink because their blood rushes
to the surface of their skin to cool them.

Seals bark like dogs!

The living world Birds spend much
of their time looking
The world of birds after, or preening, their
feathers to keep them
Only a few animals in the world are in good condition.
able to fly – insects, bats, and birds.
But none of them is more powerful Birds’ feet are
or skilled than the bird. designed for
different purposes,
Feathers are Feathered friends such as climbing,
made up of clutching berries,
tiny hair-like Birds are the only creatures or holding on
barbs that that have feathers. They to branches.
use them to fly and to
all mesh keep warm. Some birds
together. use brightly coloured
feathers for display.

A rigid “backbone” or quill
runs through the centre of the
wing feathers to strengthen
them for flying.

134 Feathers

Different feathers
have different
jobs on a bird.

Outer wing: strong
feathers to provide
power in flight.

Inner wing:
smooth and flat
to help flight.

Tail feather: long
and thin for steering and
balancing during flight.

Body feather: soft and
downy to keep a bird warm.
Some have exotic colours.

What is the world’s smallest bird?

Flight The world of birds

A bird can fly because it has wings and There are two methods
a very light skeleton – many of the bones of flying; flapping, like
are hollow. Birds have short and this red-tailed minla,
compact bodies that make and gliding.
them neat fliers too.
Red-tailed
By flapping minla
its wings up
and down, the
bird remains
in the air.

Travelling birds
About one-third of
birds spend summer

in one place then
when the winter sets in

they fly thousands of
miles to a warmer spot.
Often they go to exactly the
same places year after year.

Feet Bills Communication
All birds have good hearing
The shape of birds’ The shape and size of a so they can respond to songs
feet vary depending bird’s bill, or beak, can from other members of their
on where they live. show what they eat. family. Birds are well known
for their tunes, and some,
Eagle foot: birds of prey Duck: wide and flat to
have sharp talons to kill tear plants and filter like this parrot,
and grip animals. food underwater. even speak.

Perching foot: songbirds Woodpecker: long 135
have three toes in front and and hard to chisel into
one behind for perching. wood and pick out insects.

Webbed foot: waterfowl Chaffinch: short and
have webbed feet to help cone-shaped, ideal for
them to paddle on water. cracking seeds.

Ostrich foot: two thick Heron:
toes help this flightless long, ideal to stab
fish underwater.
bird to run very fast.

The smallest bird in the world is the bee hummingbird.

The living world

The world of reptiles

Reptiles are egg-laying Eating habits
animals that have a tough
skin covered in scales. They Reptiles are meat eaters, with
live on land and in water. the exception of tortoises,
which move too slowly to
The reptile groups Reptiles can catch fast-moving prey.
eat huge Lizards, such as this
There are four main meals, then gecko, can eat half their
groups of reptiles: go without own weight in insects
food for days. in one night.

The tortoise family: Most reptiles, All reptiles
these reptiles all have swing their shed their
a shell over their body. bodies from skin from
side to side time to time.
Snakes and lizards: when walking.
the majority of reptiles
fall into this group. Flying gecko

The crocodile family: Hot and cold
this group are the giants Reptiles have scales,
of the reptile world. which can control how
much water they lose
Tuataras: these reptiles through their skin. This
are very rare and look means they can live in
a bit like lizards. dry places. They are
cold blooded, however,
so rely on the climate to

keep their temperature
in check.

European eyed
lizard

136 Reptile babies This lizard, which lives in the desert,
Nearly all reptiles lay basks on rocks to warm up its body.
eggs, which hatch into
miniature versions of
their parents. A few,
such as this slow
worm, however, give
birth to live young.

What is the longest snake in the world?

Tuataras live in The world of reptiles
burrows and hunt
at night. They can Living fossils
live for 100 years.
Tuataras are the only survivors
Scaly skin of a group of reptiles that
lived with the dinosaurs
A reptile’s skin is covered millions of years ago.
with scales made of Today they live on a
keratin, like your nails. group of islands off
New Zealand.
Tortoise: the shell
of a tortoise has lots of Reptile relatives
large, hard scales on it. The reptiles of today are
the last living relatives of
Lizard: Lizards’ scales dinosaurs and look very
have stretchy skin similar to their ancient
between them. ancestors. You can see
similarities between the
Crocodile: these Tyrannosaurus rex and
scales are strengthened
in between by bony plates. this lizard.

Snake: the skin on snakes Tyrannosaurus rex
has overlapping scales for
extra protection.

Become Collared
an expert lizard

138-139 The world
of amphibians

144-145 The world
of fish

The reticulated python can reach lengths of 10 m (33 ft). 137

The living world

The world of amphibians

Fire Amphibians are different Amphibian family
salamander from reptiles in that they
have smooth skin with no There are three groups
in the amphibian family.
scales. They are born in
water then live on land Frogs and toads: these
or in water when amphibians have no tail
they grow up. and big back legs.

Newts and salamanders:
these lizard-shaped animals
live on land or in water.

Amazing skin Caecilians: these
worm-like creatures
Most adult amphibians, such as this
salamander, can breathe through have no legs.
their skin as well as their lungs.
In order for the skin to Frog
breathe it has to be kept
moist, which is why
most amphibians
like to live
near water.

Some frogs
live in water...

Become
an expert

142-143 The world

of non-insects Colourful creatures
144-145 The world Many amphibians are incredibly

of fish colourful creatures. Some are

spotted, others are striped and

some are just very bright.

138
What is the world’s most poisonous frog?

The world of amphibians

A choice of home

Frogs and toads can
live both on land
and in water.
Some even
live in trees.

Land frogs tend to Water living
be more rounded Some salamanders
in shape than spend the whole of
water frogs. their lives underwater.
This cave salamander does not
have any lungs; it breathes through its
skin only. It is almost completely blind.

e in the
s!
l treliev
...other frogs ptroepfesrotfCotaalecilians

Legless caecilians are rarely seen by

humans because they live either under

water or under ground. They have a

pointed head, which they use as a shovel.

If an animal is poisonous like this tomato frog, it
is often a very bright colour that warns predators.

Travelling parents Common
newt
Each spring salamanders,
newts, frogs, and toads 139
lay their eggs in ponds
or streams. Some travel

5 km (3 miles) to get there.

The most poisonous frog is the bright-yellow poison-dart frog.

The living world

The world of insects

A huge majority of creepy crawlies are Remember,
insects. In fact there are more types of insects have
insect in the world than any other 3 + 3. Three
animal. They are absolutely pairs of legs
everywhere. Some are almost too small and three
to see and others are surprisingly large. body parts.

When a pile Most insects Beetle
of dung have two pairs
appears in of wings.
Africa, dung
beetles are on What is an insect?
the scene in You can tell if a creepy
minutes. crawly is an insect because
insects always have six
The beetles roll legs. They also have three
perfect balls of body parts – a head, a
dung in which thorax, and an abdomen.
they lay a single
egg. When the
egg hatches,
the larva eats
the dung.

Nature’s recycling service

Although many people dislike insects

and they can be pests, they are also

essential to our world. In

fact we could not live

without them. For

instance, these

dung beetles

do a very good

job cleaning Dung
up dung. beetles

140
Apart from honey, what else does a bee produce that we can use?

Useful insects The world of insects
Pest control
Here are some other
ways that insects Sometimes insects, such as
are useful to us. aphids, eat huge amounts of
our crops. The best way to get
Red food dye: this food rid of them is to introduce
colouring is made from another insect that likes
the bodies of scale insects. to eat them. Ladybirds
are often used for
Silk: believe it or not, the aphid pest control.
silk you wear is made by
silk-moth caterpillars! Aphid

Honey: if there were Introducing insects that
no bees in the world, eat other insects is called
we would have no honey. biological pest control.

Food: to some people, Ladybird
such as the Australian
aborigines, grubs are a meal.

As old as an insect Aphids
We know that breed so
insects were around quickly that it
40 million years ago is difficult to
because some were control them.
trapped in a tree resin
called amber, which Become
hardened back then an expert
and preserved them.
142-143 The
world of

non-insects
152-153 Micro

life

141
and their poison is used as medicine. Bees produce wax

The living world

The world of non-insects

There are many creepy crawlies
scuttling around our planet that
are not insects. Some live on
land, others live in fresh water
or the sea. They come in all sorts
of weird and wonderful shapes.

Arachnids The worm family
Segmented worms like
Spiders, scorpions, ticks, and mites belong earthworms are simple
animals that have a
to a land-dwelling family called arachnids. head at one end, a tail
at the other, and lots of
All arachnids have eight legs and two segmented body parts
in between. They live
body parts. on land or in water.

Tarantula

Despite their reputation, most
spiders are harmless to humans.

A tarantula has
hairs on its legs
that can cause

bad irritation.
When the
spider is

annoyed, it
flicks them out
at the enemy.

142
How big can spiders grow?

Odd sea creatures The world of non-insects

The sea contains some Molluscs
very strange animals Snail Slugs, snails, squids,
indeed. Here are a few:
and oysters, are
Sponge: these molluscs. Some live
animals were once on land and some
thought to be plants. live in water.

Starfish: most starfish Snails are The octopus,
have five arms to crawl found on land which is also
across the sea floor. and in the sea. a mollusc, is a
very intelligent
Anemone: these creature.
flower-like sea animals
have no brains.

Centipede

Centipede Millipede Centipedes have
one pair of legs on
Centipedes and millipedes each segment and
If you try counting the legs on an millipedes have
insect and you find there are too two pairs on each.
many, the chances are you have
found a centipede or millipede. Crustaceans
They have lots and lots of legs.
Most crustaceans, such as lobsters, crabs, and
shrimps, live in water. Only the woodlouse
lives on land. They often have a shell and
their eyes are on stalks.

Lobster

Some spiders can grow as big as dinner plates! 143

The living world Types of fish

The world of fish There are over 24,000
types of fish, which
Fish have been around for 400 million fall into three groups.
years! They live in seas, rivers, and
lakes. Wherever you find water, Bony fish: 95% of the fish
you can bet there are plenty in the world are bony fish
of fish swimming around. with hard skeletons.

Pyjama Cartilaginous fish: rays,
cardinalfish skates, and sharks
make up this group.
Bony fish have Fish skin, made
a skeleton with up of scales, is Jawless fish: only
a skull, ribs, and slimy to let them hagfish and lampreys
a backbone. slip through fall into this small group.
water easily.
The gills lie
behind the eyes.

The tail of a fish sweeps Fish have fins Gills
from side to side to that keep them
push the fish forwards. upright when Like other
they swim. animals, fish
Mudskipper need to take in
oxygen in order to live.
144 But, unlike us, they can
breathe underwater using
their gills. Fish gulp in water and
their gills filter the oxygen out of it.

Fish out of water
Mudskippers are one of the only fish that can
survive out of water. They have special gills
that take oxygen from air or water. They skip
along mudflats using their fins as elbows.

Which fish is the slowcoach of the sea?

The world of fish

The art of swimming

Scales Many fish swim like snakes slide –
Most fish are covered in hundreds they wriggle in an ‘s’ shape. Their
of scales that overlap like roof tiles. whole bodies move from side
Tiny animals can get under the scales to side and their tails flick
and harm them, so fish let other to push them forwards.
creatures give them a regular clean. Their fins help to
steer them.
Mandarin Colours can
fish be used for Some fish can
camouflage turn on their sides
or to attract and roll right over.
a mate. A few can even
swim upside-down!

Colour

Fish come in all

colours and patterns. Carp

Freshwater fish and those living

in cooler waters tend to be duller in

colour. Tropical fish are sometimes

incredibly bright and beautiful.

Eels are found Living together
in fresh water Fish sometimes swim
and sea water. in huge groups called
schools. When so many
Fishy features swim together they look like
Most fish look like the one big fish so they are less
pyjama cardinalfish on
the left. Some however have likely to be attacked.
a different appearance. This eel
looks more like a snake with fins. 145
Unlike a snake it has sharp teeth.

The seahorse is the slowest fish that lives in the sea.

The living world

What is a plant?

Plants make their own food from the Seaweed
Sun’s rays. Most have leaves that Seaweed looks like a
reach outwards to capture sunlight, plant, but is an algae.
and roots that dig deep for nutrients It doesn’t have roots,
and stability. so it has to stick to rocks
or float with the tide.
Plant parts
The petals attract
There are loads of different insects and birds
plants, but most are made that collect pollen.
of the same vital parts –
roots, stems, leaves, The stamen and
and flowers. carpels form the
reproductive organs
Stems of a plant.
Stems support the leaves
Flowers
and flowers and allow Flowers are key to plant
water and food to flow reproduction. They make
from the roots to the leaves. pollen and develop seeds
and fruit.
Roots
These are the foundations Leaves
These are the work factories
of the plant. They dig of the plant and capture the
deep into the dirt giving Sun’s energy.

stability, as well as Weird or what?
sucking up nutrients.
The Venus flytrap doesn’t
Water lily just get its energy from
The water lily’s flat leaves the Sun. It also lures and
float on the pond surface, feeds on unsuspecting
as its roots sink into the
pond bed. insects. Yum!

146 What plant has the largest leaves?

What is a plant?

Types of plants

Have a look around you. Not all plants are the
same. But some plants are more similar than others.

Fern leaves unfurl Ferns Most conifer
as they grow. trees keep their
Ferns love damp and leaves all year
shady areas. They round.

have prong-like
leaves and spread
using spores.

Moss Conifers The sequoia is
the largest tree
Mosses love
in the world.

Conifer trees grow cones

moisture and grow that store their seeds.

in clumps. They Most conifers have

don’t have roots needle-shaped leaves.

or grow flowers. There are about You can
12,000 species of moss. identify a tree
Flowering plants by the shape
of its leaves.

This is the biggest group of plants.

They produce flowers, fruits and Maple leaf
seeds, which mainly grow in
seasonal cycles. Ash leaf

Rainforest Scarlet
These warm and oak leaf
wet forests are home
to nearly half the
world’s plant species.

Deciduous Ash leaf
Deciduous plants
shed their leaves 147
to save food and
survive drier seasons.

The raffia palm has leaves that grow up to 24 metres (79 feet) long.

The living world The Sun’s energy
is trapped in the
How plants work leaves, and helps

Plants have an amazing make food.
system for making
and transporting Cross-section
food to all their through a
different parts. leaf vein

Photosynthesis Food is moved from leaves
to roots and growing tips,
The green pigment along a set of tubes called
chlorophyll traps sunlight phloem vessels.
in the leaves. The Sun’s
energy is then used Some water evaporates through
to change water and tiny holes called stomata in the
carbon dioxide into sugar. surface of the leaf. This process
is called transpiration.
A waste product of Tiny tubes called xylem vessels
photosynthesis is carry water up the stem from
oxygen, which animals the roots to the leaves.
need to survive. Cross-section
through a
Veins carry water stem
around the leaf.

nd.
Roots suck water up from the grou
148
Are plants the only organism to use photosynthesis?