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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?