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Published by IMAX, 2020-02-13 01:03:30



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SCIENCE 4 TEXTBOOK – 1 Name: ___________________________________ Section: ________________ Roll No.: _________ School: __________________________________

Preface ClassKlap partners with schools, supporting them with learning materials and processes that are all crafted to work together as an interconnected system to drive learning. Our books strive to ensure inclusiveness in terms of gender and diversity in representation, catering to the heterogeneous Indian classroom. ClassKlap presents the Traveller series, designed specifically to meet the requirements of the new curriculum released in November 2016 by the Council for the Indian School Certificate Examinations (CISCE). Guiding principles: The 2016 CISCE curriculum states the following as its guiding principles for Science:  Theme-based learning  Relating science learning to the daily-life experiences of students  Focus on skill/process development  Providing opportunities for knowledge construction  Infusion of environmental issues into the content Each of these principles resonates with the spirit in which the ClassKlap textbooks, workbooks and teacher companion books have been designed. The ClassKlap team of pedagogy experts has carried out an intensive mapping exercise to create a framework based on the CISCE curriculum document. Key features of ClassKlap Traveller series:  Theme-based content that holistically addresses all the learning outcomes specified by CISCE curriculum  Opportunities for experimentation, analysis and synthesis of ideas and concepts  Exposure to locally relevant environmental problem solving  Focus on science-specific vocabulary building  Promotion of participatory and contextualised learning through the engagement of all relevant stakeholders in the learning process All in all, the Traveller Science books aim to enhance the learning of science, development of scientific temper and curiosity towards scientific activities along with the inculcation of healthy habits for environmental protection. – The Authors

Textbook Features • Use of simple, age-appropriate language • Activity-based approach to learning • Use of infographics and pictures to explain concepts and terms • Focus on subject-related vocabulary building I Think I Will Learn About • Introduces the concept/ • Lists the key learning subtopic in a manner as to outcomes of the lesson arouse curiosity and interest among students ? In-text Questions Pin-Up-Note • O ral discussion questions to check for learning and to • H ighlights the key points or gauge the understanding definitions level of the child Connect the Dots A Be Amazed • F osters interdisciplinary • Fascinating facts and trivia thinking by connecting other related to the concept subjects to an aspect of the taught concept Inside the Lab A Note to Parent • H ands-on experience • E ngaging activities to be done provided for creating, at home along with parents to designing or implementing reinforce the concept something innovative and/or useful based on the concept learnt

Contents 1 Components of Food �������������������������������������������������������������������������������������1 2 Teeth to Treasure ��������������������������������������������������������������������������������������������8 3 The Digestive and Excretory Systems ���������������������������������������������������������14 4 Adaptations in Animals ��������������������������������������������������������������������������������21 Inside the Lab − A ������������������������������������������������������������������������������������������������28 Activity A1: Same Food Items Go Together Activity A2: Food as Fuel 5 Adaptations in Plants �����������������������������������������������������������������������������������30 6 Food Production in Plants ����������������������������������������������������������������������������36

1Lesson Components of Food I Will Learn About • components of food. • balanced diet. • different food for different age groups. • ways to avoid food wastage. I Think Ali is a football player. His football coach has told him to eat food items that will help him build a strong body. Ali wondered what food items he should add to his diet. All living things need food to live. The food we eat contains nutrients that keep us healthy and strong. These nutrients help our body to do work, grow, fight disease-causing germs and repair itself. Let us learn about these nutrients in detail. Components of food The food we eat contains five main nutrients: carbohydrates, proteins, fats, vitamins and minerals. Food also contains water and fibres. All these components are needed by our body to function properly. Carbohydrates: Carbohydrates give energy to our body. We need carbohydrates in large quantities. Energy-giving food, such as fruits and cereals, is rich in carbohydrates. Food rich in carbohydrates 1

Sugar and starch are the two main types of carbohydrates. Fruits contain sugar. Cereals like wheat, rice, maize and oats are rich in starch. ? G ive two examples of carbohydrates. Proteins: Proteins help in body growth and repair. They also make our body strong. So, the food items rich in proteins are called body- building food. Milk and milk products, pulses, soya bean, meat and eggs are rich sources of protein. Fats: Our body needs very little amount of fat. Food rich in proteins Excess fat gets stored in our body. This stored fat is used by the body for producing energy as and when required. So, fat is considered as the energy bank in our body. But having lots of fat in our body is harmful to us. Butter, ghee, milk, egg yolk, nuts and cooking oils are the major sources of fat. Vitamins: Vitamins help in the growth of our body and protect it from various diseases. The food we eat contains six types of vitamins: A, B, C, D, E and K. Each vitamin has a special role to play. Leafy green vegetables and carrots are rich in vitamin A. They improve our eyesight. The vitamin C in oranges and lemons helps our body to heal from a cut or bruise. Milk, fish and eggs are rich in vitamin D. They keep our Food rich in fats bones and teeth healthy. 2

d Be Amaze A Did you know that human skin makes vitamin D by absorbing ultraviolet (UV) rays of sunlight? So, if we do not go out in the sun at all, our body will not be able to make vitamin D. Minerals: Our body needs minerals in very small quantities. Iron and calcium are two important minerals that our body needs. Leafy green vegetables and apples are rich in iron. Iron is an important part of our blood. Milk, curd and cheese are rich in calcium. It helps our teeth stay strong. ? Name a food item that is rich in calcium. Fibrous food Fibres: Fibres are the part of food from plants that does not give any nutrient but helps in maintaining a good digestive system. They help us in smooth and regular stomach movements. Salads, leafy green vegetables, sprouted grains and fruits like oranges and bananas are some sources of fibre. Water: It is a very important component of our food. It helps our body to get nutrients from food. It also helps to throw out waste from our body as sweat and urine. Components of Food 3

Milk, fruits and vegetables contain water. The main components of the food we eat are carbohydrates, We have learnt that all components of food proteins, fats, vitamins, minerals, have some important roles. So, the food we eat fibres and water. must have all the nutrients present in it. Balanced diet The food we normally eat in a day is our diet. Our diet must contain all the nutrients in the right or balanced amount. This is called a balanced diet. Lack of one or more nutrients in our food for a long time may cause certain disorders in our body. The diet that contains all the food For example, lack of protein causes components or nutrients in the right kwashiorkor; lack of iron causes anaemia. amount is called a balanced diet. Proteins Fats Carbohydrates Vitamins and minerals Balanced diet ? Name a disorder caused by lack of iron in our diet. Do you have a baby brother or sister? Do they have the same type of diet as you? What about your grandparents? According to our age, our body’s need for different nutrients changes. Let us learn about this in detail. 4

Different food for different age groups People of all age groups need a balanced diet to be healthy. But, the components of a balanced diet differ according to the age group. The diet of children should include more of body-building and energy-giving components that help in growth and development of the body. Adults do not grow like children. But, they need energy to do work and need to keep their body healthy and fit. So, their body needs different amounts and kinds of food as compared to children. Older adults are less physically active. They cannot have all kinds of food. They should avoid fat. They should have food that contains proteins, vitamins and minerals to maintain the body and protect it from diseases. They should eat a lot of fibre. Food is important to everyone. Many people do not have enough food to eat. We should conserve food so that there is enough for everyone. Ways to avoid food wastage We can do the following things to avoid food wastage. 1) Itis better to take small servings than to throw excess food in garbage bins. If the served food is not enough, you can always ask for more. 2) Ask your mother to pack lunch that you can finish or share with a friend. If you bring it back home at the end of the day, it may get spoilt. Then, it will have to be thrown out. 3) Ifyou are not eating something, you can share it with a friend or family member who wants it. 4) Ifyou are on the road, instead of throwing away your leftover food, you can give it to needy people. 5) Ifyou have left some food on your plate, Food stored in and it is not spoilt, you can store it in a a refrigerator refrigerator. You can eat it later when you feel hungry. Most food items get spoilt if not stored properly, and then we have to throw them. This can be avoided by storing food properly. Storing food without losing the nutrients in it is called food preservation. Components of Food 5

Storing food in a refrigerator or deep freezer helps to preserve food. We can also make pickles, jams or jellies of vegetables and fruits. Some food items can be preserved through canning. Pickled and canned food Connect the Dots Maths Fun Out of 7 food items in a food packet, 3 contain carbohydrates, 2 contain proteins and 1 contains fats. Represent this information using fractions. Total number of food items in the packet = Fraction of food items that contain carbohydrates = Fraction of food items that contain proteins = Fraction of food items that contain fats = 6

English Fun Put the food components in alphabetical order. Write the correct order in the brackets. proteins [ _______________________ ] fats [ _______________________ ] carbohydrates [ _______________________ ] minerals [ _______________________ ] vitamins [ _______________________ ] A Note to Parent Discuss with your child the importance of having a balanced diet. Help your child to make a weekly diet plan. Day of the week Diet plan Sunday Monday Tuesday Wednesday Thursday Friday Saturday Components of Food 7

2Lesson Teeth to Treasure I Will Learn About • teeth of infants and adults. • different kinds of teeth and their functions. • structure of a tooth. • care of teeth and gums. • healthy food for healthy teeth and gums. I Think Anagha had a toothache. Her mother took her to a doctor. The doctor told her mother that one of her molars has a cavity. Anagha did not understand what molars and cavity are. Do you know? We all have a set of teeth inside our mouth. Molars are one kind of teeth among them. What do molars look like? What are the other kinds of teeth that we have? Try this! 1) Ask one of your classmates to open his/her mouth and show his/her teeth to you. 2) Count the total number of teeth that he/she has. Do all the teeth look alike or are they different in shape? Did you find any gap between them? 8

dTeeth of infants and adults At the time of birth, human babies normally do not have any teeth. By the age of two and a half years, children get the first set of 20 teeth. This set is called milk teeth or temporary teeth. Be Amaze A The milk teeth start to form when a human baby is inside the mother’s body. They do not normally come out through the gum until the baby is around six months old. But, some babies are born with one or two visible teeth! Milk teeth start to fall out one by one after children turn about six years old. By the age of 13, the temporary teeth fall and new ones grow in their place. This new set of teeth is called permanent teeth. Adults usually have 32 teeth. They are of different shapes and sizes. Some are flat, while some are sharp-edged. Up to the age of 13 years, 28 of the 32 permanent teeth will appear. The remaining teeth appear between the ages of 17 to 25 years. Now, let us learn about the different kinds of teeth in detail. Different kinds of teeth and their functions Adult humans have four kinds of teeth. 1) Incisors: They are the front teeth; eight in all. There are four on the top and four at the bottom. 2) Canines: They are four in all. We have one canine on both sides of the incisors: two on top and two at the bottom. 3) Premolars: They are eight in number: four on top and four at the bottom. They lie behind the canines. 4) Molars: They are twelve in all: six on top and six at the bottom. They lie right behind the premolars. Molars Incisors Premolars Canine Different kinds of teeth in humans Teeth to Treasure 9

Why do we have different kinds of teeth? Let us find out. Try this! Try to bite a piece of carrot. Which teeth did you use? You must have used the front teeth, which are incisors. They have sharp edges that help us bite and cut the food. Now, chew the carrot Incisors help us to cut and bite food pieces well. Which teeth Premolars and molars help us are helpful in chewing? to chew and grind our food Premolars and molars. They are broad and have a flat surface, which help us to chew and grind the food. ? Which kind of teeth help us to chew and grind our food? Which teeth do we use if we want to tear some food items? We will need sharp and pointed teeth. Canines help us to do that. The primary teeth of infants have eight incisors, four canines and eight molars. Premolars are absent in the primary teeth set. Adult humans have Do you know that the tooth Canines help us to tear four different kinds of we see is just the outer part our food teeth: incisors, canines, of a tooth? It has many premolars and molars. parts hidden inside it. Let us Infants do not have learn about the different parts premolars. of a tooth. Structure of a tooth A tooth has two main parts: the crown and the root. The part we see is called the crown. The hidden part inside the gums is called the root. The gums protect the socket made of bone where the tooth is fitted. A tooth has different layers. ? Name the hardest material in the human • Enamel: It is the outermost, white layer. It is the body. hardest material in the human body. 10

• Dentine: This layer is under the enamel. It is not as hard as the enamel. It forms the bulk of the tooth and can be sensitive if the protection of the enamel is broken. • Pulp: It is the innermost, soft part of the tooth. Enamel Crown Dentine Root Pulp Gums Bone Structure of a tooth You now know about human teeth and their structure. A tooth has three What will happen if the hard layers of our teeth become layers: enamel, dentine weak, or the gums cannot hold our teeth firmly? and pulp. Care of teeth and gums We eat different kinds of food every day. Some part of this food gets stuck in the grooves of our teeth or in between the teeth. Germs will grow in them if we do not clean the teeth and gums properly. The growth of germs will cause bad breath, swelling and pain in the gums. Moreover, the teeth may turn yellow in colour, and holes may start to form in the teeth. These holes that are formed due to the decay of the enamel are called cavities. We should take good care of our teeth by: • rinsing our mouth after meals to remove all the tiny bits of food stuck in the spaces between the teeth. Teeth with cavities Teeth to Treasure 11

• brushing our teeth twice a day; once in the morning and once before going to bed. • massaging our gums. • visiting a dentist for regular checkups of teeth. Healthy food for healthy teeth and gums To have strong and healthy teeth and gums, we should: • eat healthy food that is rich in minerals, especially calcium and vitamins. For example, apples, cheese, yogurt, beverages and dry fruits. • have leafy vegetables, milk products and pulses. • avoid eating a lot of sugary food items. • avoid soft drinks, chewing gum and chocolates. Connect the Dots English Fun Write a diary entry about the day your first milk tooth fell out. 12

Maths Fun You have learnt about fractions in mathematics. Can you write the fraction of milk teeth to the total number of teeth we get in our lifetime? (Hint: We generally get 20 milk teeth + 32 permanent teeth = 52 teeth in our lifetime) The total number of teeth we get = 52 The number of milk teeth we get = 20 So, the fraction of milk teeth to the total number of teeth we get in our lifetime = A Note to Parent Take your child to a dentist for regular checkups. Request the dentist to explain to your child the proper way of brushing teeth. Teeth to Treasure 13

3Lesson The Digestive and Excretory Systems I Will Learn About • the organs of the digestive system and their functions. • the organs of the excretory system and their functions. • healthy habits related to digestion and excretion. I Think Our elders tell us to chew our food properly before swallowing. Do you know why? We do a lot of work throughout the day. We need energy to work. Where does this energy come from? This energy comes from the food we eat. We have learnt that food contains different nutrients that help our body to work. Our body cannot absorb these nutrients directly from the food we eat. So, the food we eat is broken down into smaller parts that can be absorbed by our body. This process is called digestion. We learnt in previous classes about organs and organ Digestion is the process systems in our body. The organ system in our body that of breaking down of helps in breaking down the food into smaller parts is food into smaller parts that can be absorbed called the digestive system. by our body. 14

The organs of the digestive system and their functions Look at the given picture of the digestive system. The following organs together make the digestive system. Mouth: We take food into our Food pipe: It is a long tube that mouth. Digestion starts here connects the mouth to the with the help of the teeth, stomach. tongue and saliva. Stomach: It is a stretchy, Liver: It is the largest and bag-like organ. It is about heaviest organ inside the body. It is reddish brown the size of a tennis ball in colour. when it is empty. It Large intestine: The expands nearly to the large intestine is also size of a football after like a tube. It is about five feet long. a big meal. It is called the large intestine because it is Small intestine: It is a wider than the small intestine. long, narrow tube. It is about twenty feet long. Anus: It is the opening at Rectum: It is the last part the end of the digestive of the large intestine. system. ? Name the largest and heaviest The parts of the organ inside the body. digestive system are the mouth, food pipe, How do all the parts of the digestive system help to break stomach, liver, small down food? What happens to the food we eat? Let us find intestine, large intestine, out. rectum and anus. The process of digestion starts in the mouth. We chew the food with our teeth. We have different types of teeth to chew the food and break it into pieces. Inside the mouth, saliva mixes with the food. It makes the food soft and wet. Teeth can now easily break this wet food down into smaller pieces. The Digestive and Excretory Systems 15

The tongue helps in mixing the food with saliva. It also pushes the chewed food towards the food pipe. The food pipe moves the food from the back of our throat to our stomach. Stomach walls make squeezing and relaxing movements. These movements mix the food with stomach juices. Stomach juices help to break down the food. From the stomach, the food is pushed into the small intestine. The liver produces bile juice. It helps in the digestion of food. In the small intestine, bile juice mixes with food and breaks it down further. The walls of the small intestine absorb all the useful parts of the food. The digestion of the Stomach movement food gets completed in the small intestine. The remaining undigested material is pushed to the large intestine. When the food passes through the large intestine, water and some minerals get absorbed by the walls of the large intestine. The remaining waste matter called faeces is pushed into the rectum. The rectum stores the faeces for a short time. Then, it is thrown out of the body through the anus. Be Amaze A d Did you know that around 1.7 litres of saliva is produced in our mouth every day? The salivary glands in our mouth produce saliva. We have learnt that the digestive system breaks down food, absorbs nutrients and water, and throws out the remaining solid waste as faeces. Along with food, we take in water and other liquids. Leftovers from these form liquid waste inside our body that needs to be thrown out too. The removal of solid and liquid waste from our body is The excretory system called excretion. The organ system that removes the liquid helps to throw out waste from our body is called the excretory system. liquid waste from our body. 16

The organs of the excretory system and their functions Look at the diagram of the excretory system. The excretory system includes the following Kidney organs. 1) A  pair of kidneys: They are two bean- Ureter shaped structures located near our Bladder stomach, with one on each side of our backbone. The kidneys are about the size of our fist. 2) A  pair of ureters: They are pipe-like structures. A ureter is attached to each kidney. 3) Urinary bladder: It is a bag-like organ that Urethra expands as it fills with urine. It is balloon- shaped when completely filled. The human excretory system 4) Urethra: It is a pipe-like structure at the end of the bladder. It opens outside the body. ? Name the organs of the excretory system. The parts of the excretory system are: How does the excretory system help in the excretion of a pair of kidneys, a liquid waste? Let us find out. pair of ureters, urinary bladder and urethra. As the blood travels throughout the body, it collects excess water and salts that need to be thrown out. Then, this blood carrying waste enters the kidneys. The kidneys work like filters. They filter the blood that passes through them. It takes about 45 minutes for the kidney to purify (clean) all the blood in our body. Kidneys work throughout the day. Kidneys send all the filtered-out waste to the bladder through the ureters in the form of urine. The urinary bladder stores this urine. Once the bladder is almost half full, we feel like urinating. The urine stored in the bladder is thrown out of the body through the urethra. In this way, liquid waste is removed from the blood and thrown out of our body as urine. Some other organs like the skin and the lungs also help in removing excess from the body. Let us see how this happens. 1) E xcretion through the skin: The skin is the largest excretory organ in our body. The liquid waste from our body is also thrown out in the form of sweat. It is made up of extra water and salts from our body. Sweating cools our body. Sweating The Digestive and Excretory Systems 17

2) E xcretion through the lungs: We breathe in and out with Breathing the help of our lungs. During breathing, the lungs absorb the oxygen from the air we breathe. At the same time, carbon dioxide is thrown out of the body as waste from the lungs. ? Name the largest excretory organ in our body. Healthy habits related to digestion and excretion What will happen if our digestive and excretory systems do not work? The food we eat will not get broken down. We will have indigestion. This may cause acidity, constipation (irregular bowel movements), vomiting and loose motion. If the excretory system does not work properly, the liquid waste will get collected inside the body. This may lead to the swelling of the body, especially on the legs, hands and face. If our kidneys do not work properly, the colour and smell of urine may change. We may feel tired, or we may start vomiting. So, to be healthy, we should take care of our digestive and excretory systems. Let us learn some healthy habits that help in the proper functioning of digestion and excretion processes. 1) W ash your hands and mouth properly before and after eating food. 2) A lways sit down and eat the food slowly. 3) C hew the food well. It breaks down food into smaller particles. It allows proper mixing of saliva with food, which makes the process of digestion easier. 4) D rink plenty of water every day. a) W ater is necessary for proper absorption of nutrients. It also helps in enabling easy movement of food through the intestines. Without water, the food material will become dry and will not move properly through the intestines (bowels). This will cause constipation. b) A lack of water in our body may also lead to excess salts and minerals in the urine. These salts and minerals may form stones in the kidneys. Small kidney stones pass out of the body through urine without causing any problems. But, when they are of bigger size (the size of a pea), they block the ureter. This causes pain. Kidney stones 18

5) We should not drink water along with or immediately after our meals. When saliva and other digestive juices mix with water, they cannot break the food down easily. 6) Always eat a balanced diet and avoid junk food. Eat food that is rich in fibre like leafy vegetables. Fibres help in the easy movement of food through the intestines. 7) E a t food on time at regular intervals. 8) Never try to resist the feeling to urinate or defecate. Holding on wastes inside our body for a long time is harmful to our body. 9) W e should bathe regularly to remove sweat and dirt from the skin. 10) W e must do breathing exercises to keep the lungs healthy. We must protect our lungs from dust and smoke by wearing a mask when we go outside. Connect the Dots English Fun Find the origin of the following words. 1) excretion 2) ureter 3) lung 4) liver The Digestive and Excretory Systems 19

Maths Fun The human intestine (including both small and large intestines) is usually 8.5 metres long. That is almost the height of eight children of your age standing on top of one another! The human intestines A Note to Parent Tell your child why it is important to chew food properly. Also, talk about the importance of eating food at regular intervals and drinking plenty of water. 20

4Lesson Adaptations in Animals I Will Learn About • the need and reasons for adaptation in animals. • adaptations of animals according to their habitats. • adaptations of animals according to their food habits. • care for animals. I Think Mona wonders why an elephant has a long trunk and a fish has fins. Can you guess why they are different? The need and reasons for adaptation in animals We find animals in forests, grasslands, water bodies and so on. A place where an animal lives in nature is called its habitat. Animals develop some special features with time that help them to live in a particular habitat. Sometimes, they may show some changes in their behaviour. These special features and behaviours are called adaptations. Animals need adaptations to find food, water, shelter Adaptations help the and so on. They also need to adapt to take care of their animals to survive in young ones. Sometimes, they need to adapt to protect their habitats. themselves from their enemies. 21

Adaptations of animals according to their habitats Animals have specific body parts and behaviours that help them to survive in their habitats. Some animals like to live in groups: for example, deer, elephant, bison and so on. By living in groups, they can find food easily. They can also protect themselves and their young ones from their enemies. Herd of bison Herd of elephants Herd of deer Herd of horses A shoal of fish A flock of birds ? Name an animal that lives in groups. Some animals like to stay alone: for example, tiger, bear and so on. They can find food and shelter on their own. They can also protect themselves even when they are alone. Tiger Leopard Bear 22

Animals that live in cold regions have a thick layer of hair (fur) on their bodies. It helps to keep their bodies warm. Sometimes, animals like the polar bear, which live in extremely cold regions, eat a lot. They then go for a winter sleep (hibernation) to avoid the cold climate in winter. Animals living in hot regions also show some Polar bear adaptations. Animals like camels, which live in deserts, have thick pads under their feet. These soles protect their feet from being burnt by the hot desert sand. The webbed toes of the feet protect them from sinking into the loose sand. Animals like snails and crocodiles go for a Camels have thick pads under their feet summer sleep (aestivation) to avoid dryness and heat. They go underground or rest in cool or shady and moist places. Some animals move from one place to another to escape the Crocodile hard weather conditions and to find food. For example, some birds like cranes move from the cold weather to warmer when the seasons change. Such seasonal movement of animals from one place to another is called migration. Birds have a pair of wings to fly in the air. The shape and Siberian crane weight of their body are such that they can fly in the air easily. They have air sacs inside the body to help them to fly. The tails of animals also help them to adapt to their habitat. For example, monkeys have a long tail that helps in hanging from branches and jumping from one tree to another. Kangaroos have long and strong tails to hop and balance on the ground. Some animals like tortoises and snails have shells on their Kangaroo bodies to protect the delicate inner parts. Porcupines have sharp spines for protection. Shell of a tortoise Spines of a porcupine Adaptations in Animals 23

In animals like tigers and lions, the ears facing forward help them to focus on the sound of the prey they hunt. In animals like rabbits and deer, the ears move around to help them to know the direction of their enemies. Animals that live in water (aquatic Ears of tiger Ears of deer animals) also show some adaptations in order to live in water. They have a streamlined body that helps them cut through water. Water resistance Streamlined body Direction of movement They have special body parts like fins that Gills help in swimming. Moreover, special organs Water flow called gills help them to breathe in water. into mouth ? Give an example of adaptation Frog seen in aquatic animals. Some animals can live on land as well as in water. For example, frogs. Frogs have webbed feet to swim in water. Their back legs are stronger to jump on land. They have moist skin to breathe in water. They have lungs to breathe on land. 24

dBe Amaze A Some animals can change their colour to match the colour of the place they sit in. For example, chameleons. Chameleon Adaptations of animals according to their food habits Animals differ in their food habits. Herbivores (‘herb’ means ‘a plant’, and ‘vore’ means ‘eat’): These animals eat only plant parts as their food. For example, cow, rabbit, deer, elephant and so on. They have wide jaws. They have sharp incisors to bite and flat premolars and molars to grind the food easily. Elephants have a trunk to pick up food and put into the mouth. The long neck of giraffes help them to reach out to the leaves of higher branches of trees. Rabbit Deer The trunk of an elephant ? What do we call animals that eat only plants? Carnivores (‘carni’ means ‘flesh’, and ‘vore’ means ‘eat’): These animals eat the flesh of other animals as their food. For example, lion, tiger, leopard and so on. Their sharp canines help them to tear the flesh they eat. They also have strong claws. Adaptations in Animals 25

A tiger tearing flesh A lion with canines Omnivores (‘omni’ means ‘all’, and ‘vore’ means ‘eat’): According to their These animals eat both plants and animals as their food. food habits, animals For example, humans, bears, crows, squirrels and so on. are of three types: They have sharp and strong teeth for eating both plants herbivores, carnivores and animals. and omnivores. Omnivorous birds have strong beaks and claws. Bear Crow Squirrel ? Give one example of an omnivorous bird. Care for animals Animals form an important part of our environment. Plants and animals depend on each other. Trees provide shelter to many animals. So, we should not cut trees. Hunting of animals should not be done. We should avoid using things such as leather bags and belts as they are made from animal skin. If we have any pet at home, we should take care of it by giving proper food, water, medicine and shelter. 26

Connect the Dots English Fun Make a sentence using the following words. 1) adapt: __________________________________________________________________. 2) aquatic: _________________________________________________________________. 3) claws: ___________________________________________________________________. Maths Fun Round off the number of the animals shown in the picture to the nearest tens. The total number of animals shown in the picture = _______________ The number of animals after rounding off to the nearest tens = _____________ A Note to Parent Visit a zoo with your child. Help them observe adaptations in physical features of animals. Also, discuss with them how those physical features help the animals. Adaptations in Animals 27

A Inside the Lab Make sure that you do these activities only with the help of a teacher or an adult. Activity A1: Same Food Items Go Together We have learnt about the different components of food. Can you recollect them? They are carbohydrates, proteins, fats, vitamins and minerals. Let us now try to group food items according to the components. You will need: five sheets of paper, pictures of different types of food items and sticky notes. You need to: 1) Divide the students into five groups. 2) P rovide each group with a sheet of paper, and ask them to make five columns on the sheet. Each column will be named as a component of food such as carbohydrates, fats and so on. 3) S huffle the pictures of food items and provide each group with an equal number of pictures. 4) A sk each group to identify which picture belongs to which component of food. According to this, ask the groups to paste the pictures into the correct columns. 5) A few food items may belong to two or more components. In such a case, students can add a sticky note to mention the other component/s. Activity A2: Food as Fuel Fuel is a substance that gives energy. We know that we get energy from the food we eat. So, the food we eat acts as fuel for our body. The digestive system of our body is responsible for the conversion of the food we eat into simpler substances that our body can utilise to get energy. Let us create a simple model of the digestive system to understand its structure. 28

You will need: cardboard, brown paper, tubes or rubber pipes of six different sizes (refer to the given picture), markers, stickers, adhesive materials (glue or tape), an empty soft drink can, a plastic bottle (refer to the picture), an empty juice tetra pack and an empty toothpaste tube. You need to: 1) Paste the brown paper on the cardboard using the glue or tape. 2) C ut off the bottom half of the toothpaste tube. 3) S tick the toothpaste tube (as the mouth), the plastic bottle (as the liver), the soft drink can(as the stomach) and the juice tetra pack (as the rectum) on the cardboard using the glue or tape, as shown in the picture. 4) U se rubber pipes of different sizes for the tubular organs such as the food pipe and intestines. Also, cut one small piece of the rubber pipe to represent the anus. Once cut out, arrange them in proper order and position. Now, stick these pipes to the board using the glue or tape. 5) L abel the organs in the digestive system using markers and stickers – the mouth, food pipe, stomach, small intestine, large intestine, liver, rectum and anus. Mouth Liver Food pipe Stomach Small intestine Large intestine Rectum Anus A simple model of the digestive system Inside the Lab – A 29

5Lesson Adaptations in Plants I Will Learn About • the need for adaptation in plants. • adaptations of land plants. • adaptations of water plants. I Think Sujay went to the Thar Desert with his family. He saw some unique plants there. He could not find any leaves on them. Moreover, their stems were missing. He wondered why those plants were different. Do you know? We learnt about the parts of plants in previous classes. We also learnt that the shape, size, colour and texture of these parts vary among plants. Why are there such differences in plants and their parts? Let us find out. Plants can be found almost all over the Earth. They grow on land as well as in water. These places are called their habitats. Plants have certain body features to suit to their natural habitat. Such special The body features and features are called adaptations. special characteristics that help plants to ? What is adaptation? live successfully in a particular habitat are called their adaptations. 30

The need for adaptation in plants Habitats of plants differ in weather, availability of water and minerals in the soil, availability of sunlight, the composition of the air and so on. So, they develop some adaptations to adjust to the conditions in their surroundings. For example, if a place has very little water available, plants develop features to store and save water and survive with less water. Similarly, if the habitat has a lot of water, the plants Plants develop develop features to prevent too much water entering adaptations to adjust their body. to the conditions in and Let us learn more about adaptations in plants. around their habitats. Adaptations of land plants The plants that grow on land are known as terrestrial plants. They grow in different areas like mountains, plains, deserts, coastal areas, swampy areas and so on. Mountain plants: Plants found in mountains have to protect themselves from cold and snow. If snow collects on the branches and leaves, the branches will break due to weight and moisture. Moreover, the leaves may get damaged and will not be able to make food for the plant. So, the plants in mountains Leaves of a mountain Conical shape of are tall, straight and conical plant mountain plants in shape. The conical shape does not allow snow to remain on their leaves. They also have narrow, needle-shaped leaves with a waxy coating to prevent any damage from snow. For example, pine, fir and deodar trees. Plants in plains: Plains are large, flat areas. Spread-out branches with many leaves help the plants in the plains to absorb maximum sunlight. For example, mango trees and jackfruit trees. Branched stem of a tree Adaptations in Plants 31

Desert plants: Deserts are dry land areas. These places get very little rain. So, plants living in deserts have to survive on little amount of water. For example, cactus. The leaves of desert plants are reduced to spines to prevent water loss through their surface. Stem of a cactus plant They have fleshy, green stems that store water. Such a stem also makes food for the plant in the ? Name a desert plant. absence of green leaves. The stem has a waxy coating to prevent water loss from the stem. Also, desert plants have extensive roots to absorb the maximum water available deep in the soil. Plants in swampy areas: Swampy Breathing roots Mangrove trees areas have very sticky and clayey soil. It is difficult for plants to grow in such soil because air cannot reach the roots. Hence, the plants have breathing roots. Such roots come out of the soil to help plants to breathe. For example, mangrove trees. Plants in coastal areas: These plants have to adjust to the strong winds and heavy rainfall that are common in coastal areas. Coconut trees are mainly found in Stem of a coconut tree Leaves of a coconut tree coastal areas. They have a strong and flexible stem to overcome strong winds. The thick leaves with many long strips let the wind and rainwater pass through them easily. So, they do not break during heavy wind and rain. Adaptations of water plants Water plants (aquatic plants) are of three kinds – floating, fixed and underwater plants. Floating plants: These plants float freely on water. They are not attached to the bottom of the water body. For example, water lettuce and water hyacinth. 32

Their leaves and stems are light and spongy due to the presence of air pockets. Air filled in these pockets helps the plants to float. Moreover, they have a waxy coat on the leaves. So, the leaves do not get damaged by water. Fixed plants: These plants have Water lettuce Water hyacinth roots fixed at the bottom of the water body, for example, lotus and water lily. Their leaves and flowers float on Water lily Lotus the surface of water. This helps them to get air and sunlight. They have flat and broad leaves. They also have a waxy coating on the leaves to prevent them from getting damaged due to water. Their long stems hold the leaves and flowers on the surface of water. The stems are soft and flexible. So, they can move as per the flow of water without getting broken. Underwater plants: These plants grow completely under the water, for example, seagrass and tape grass. They absorb light, air and nutrients from the water through their surface. They have divided leaves. Divided Seagrass Tape grass leaves give more surface for absorption. These plants have very small roots that generally do not have root hairs. These roots have no role in the absorption of air, water and nutrients. Their function is to fix the plant to the bottom of the water body. ? Name an underwater plant. Divided leaves of underwater plant Adaptations in Plants 33

Be Amaze d A Some plants have adaptations to suit to their food habits. For example, the pitcher plant has adaptations to trap small insects and digest them. It has leaves in the form of a pitcher (pot) with a flap. The flap produces a sweet liquid that attracts insects. The rim of the pitcher is slippery. So, the insects slip inside the pitcher. The pitcher is deep and the inside walls are difficult to climb. So, the insects drown and dissolve in the liquid present inside the pitcher. Flap Rim Pitcher Parts of a Insects on the rim An insect trapped pitcher of the pitcher inside the pitcher Connect the Dots English Fun Fill in the blanks with correct prepositions. 1) Plants grow _________ land and _________ water. 2) Lotus leaves float __________ water. 3) The roots absorb water _________ the soil. Maths Fun A lake has 3210 floating plants, 560 fixed plants and 340 underwater plants. Altogether, how many plants are there in the lake? The total number of plants in the lake = 3210 + 560 + 340 = ________________. 34

A Note to Parent Take your child to a forest or botanical garden. Show them various types of terrestrial and aquatic plants. Let them identify the adaptations of various plants. Help them to make drawings of the adaptations of plants that live in different habitats. Adaptations in Plants 35

6Lesson iFnooPdlaPnrtosduction I Will Learn About • roots and their functions. • the stem and its functions. • leaves and their functions. • photosynthesis and the storage of food. • the iodine test to check the presence of starch. I Think Rahim wonders why we eat different plant parts as food. Do you know? We learnt in previous classes about different plant products used as food. Can you recollect some of them? Plants make food with the help of sunlight, air, water and nutrients and store it in different parts. Food production in plants takes place in the leaves. To understand the process of food production, we need to learn about the different parts of the plants and their functions in detail. Roots and their functions There are two main types of roots – taproots and fibrous roots. Taproot: It consists of a thick main root (primary root) and its branches (lateral roots). The main root grows downwards. The smaller branches grow sideways from the main root. Plants such as hibiscus and carrot have taproots. 36

Fibrous root: This consists of many Primary thin, branched roots of almost root the same size. Plants like wheat, sugar cane and onion have fibrous roots. ? Name two different types of roots. What are the functions of roots? Lateral Taproot Fibrous root Let us see. roots 1) Roots help the plants to remain fixed in the soil. 2) R oots absorb water, nutrients and air from the soil and supply them to the plant. If the roots get damaged, the plants may die. 3) In plants like carrot, radish and turnip, the roots are modified to store food. The stem and its functions The stem is different in different types of plants. The stem of a big tree is called the trunk. Stems may be with Stems with branches Stems without branches branches or without branches. For example, mango trees have branches, but coconut trees have no branches. Stems are usually erect, but in some plants, they can be creeping or twisted. For example, pumpkin plants have creeping stems. In some plants such as the rose plant, we can see thorns on the stems. In some plants, stems are covered with small hair. Some stems are smooth, for example, bamboo; some stems are rough, for example, mango tree. Creeping stems of pumpkin Food Production in Plants 37

Thorns of rose Hair on tulsi Smooth stem of Rough stem or bark stem stem bamboo of the mango tree ? Give an example of a plant that has a thorny stem. Now, let us learn the functions of the stem. 1) I t allows the plant to stand upright. It holds the branches and leaves in such a way that they can get maximum sunlight. 2) It usually bears all the plant parts like leaves, flowers and fruits on it. 3) I t carries water and nutrients from the roots to the leaves. Also, it carries the food prepared in the leaves to the different parts of the plant. 4) Some stems are modified to store food for the plant. For example, sugar cane and potatoes (underground stem). Leaves and their functions Leaves are of different sizes, shapes and colours. They are arranged in different ways in different plants. Let us take a look at some leaves. Banana plants have big Banana leaves Tulsi leaves leaves, and tulsi plants have small ones. Peepal trees have heart-shaped leaves. Lotus plants have round ones. Some leaves have toothed edges, for example, neem. Some leaves have a special smell, for example, tulsi. 38

Peepal leaf Lotus leaf Neem leaves Can you recollect the parts of a leaf? Blade Have you ever wondered why leaves Vein are green in colour? This is because they Midrib contain a substance called chlorophyll Stalk that gives the green colour to the leaves. (petiole) The surface of the leaves has very small pores or openings called the stomata. Parts of a leaf There is usually more stomata on the underside of a leaf. ? What do we call the pores present on the surface of leaves? dBe Amaze A Leaves turn brown due to a substance called tannin. Tannin also gives colour to tea. The leaves of plants have the following important functions: 1) Green leaves prepare food for the plant. 2) They also help plants to breathe. Food Production in Plants 39

3) L ike we sweat through our skin, leaves of plants give out excess water in the form of water vapour through the stomata present on them. This process is called transpiration. It has a cooling effect on the plant. Photosynthesis and the storage of food The leaves of plants need sunlight, carbon dioxide, water To prepare food, leaves need sunlight, water and nutrients to prepare food. and carbon dioxide. They take carbon dioxide While making food, leaves give from the air through the stomata. Water and out oxygen. minerals from the roots reach the leaves through the stem. Sunlight Oxygen (air) Carbon dioxide (air) Water Minerals Photosynthesis Using sunlight, green leaves combine water and carbon dioxide to prepare food. During this process, they give out oxygen through the stomata. So, leaves are also called the ‘food factories of the plant’. This process of preparation of food by leaves is known as photosynthesis. The food prepared by the plants is glucose. It is a type of sugar. Plants use only a part of the food they make. The remaining food is stored in different parts of the plant in the form of starch. This is why we use different parts of plants as our food. How can we check whether any plant part has starch stored in it? Let us see. The iodine test to check the presence of starch We can test for the presence of starch by using iodine. When we put iodine solution on any substance containing starch, it turns blue-black in colour. 40

Try this! Perform the below activity with the help of your teachers. You will need: some green leaves, beaker, test tube, tweezers, water, ethanol (a colourless liquid chemical substance. It can catch fire.), iodine solution, a white tile and a burner. Burner Tweezers Test tube White tile Dropper You need to: How to test a leaf for starch 1) Boil some water in a beaker with the help of a burner. Take a leaf and put it in the hot water. Boil for two minutes. Turn off the burner. 2) Take some ethanol in a Place the Place the leaf Place the leaf on a test tube. Take out the leaf in boiling in a tube of white tile and add leaf from the beaker water for two iodine solution with and put it into the ethanol in hot the help of a dropper. test tube containing minutes. water for two ethanol. minutes. 3) Now, place the test tube in a beaker containing boiling water. Leave it till the ethanol becomes dark green. Take out the leaf carefully. Wash it with warm water. 4) Place it on a white tile. Add iodine solution with the Blue-black colour on the leaf help of a dropper. shows the presence of starch Observe the change in the colour of the leaf. 5) After a few minutes, some parts of the leaf turn blue-black. 6) This means that starch is present in the leaf. Food Production in Plants 41

Connect the Dots English Fun The word chlorophyll originated from two Greek words: ‘khloros’, meaning green, and ‘phullon’, meaning leaf. Maths Fun Observe your surroundings, and collect any two types of leaves that have a symmetry. Paste them in the space given below. Also, name them. A Note to Parent Gift a potted plant to your child. Ask them to take care of it to keep it green and healthy. Your child will be happy to observe how it grows and blooms. 42



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