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IMPORTANT FACTS AND HANDY FACTS PHYSICS CHAPTERS. MOTION AND ELECTRIC CURRENT AND ITS EFFECTS Motion is relative as it is always described with respect to some other object. For Eg. Earth is moving with respect to sun, A car is moving on the road with respect to stationary trees. What are the different types of motion? Rectilinear: Motion of soldiers moving in a march past. Circular: Motion of the merry go round. Rotational Motion: Earth moving on its own axis. Vibratory: String of a guitar. Oscillatory: Motion of a simple pendulum. When a body covers equal distance in equal interval of time and it has a constant speed, then it is said to have Uniform motion. When a body covers unequal distance in equal intervals of time and it does not have a constant speed, then it is said to have a non uniform motion. Electric Current: The flow of electric charge is called electric current. In an electric circuit, the charge is often carried by moving electrons. The SI unit of electric current is Ampere (A). The SI unit of electric charge is Coulomb. Electric Circuit:The path through which electric charge moves is called electric circuit. Symbols in Electric Circuit: Different components of electric circuit are shown by certain symbols. Use of symbols makes it easy to represent an electric circuit. Use of standard symbol makes it easy to understand for anybody. For example; a TV mechanic can identify different components of a TV by looking at its circuit diagram. . Time Measurement Devices SAND CLOCK,WATER CLOCK,SUN DIAL,PENDULUM STOP WATCHES AND CLOCKS. Sun Dial: It works on the principle of shadow of gnomon formed on the surface. Pole of sundial is known as Gnomon. • Disadvantages:It does not work on cloudy days and during the night time.Generally ,it does not give time in seconds Pendulum: Metal Ball of pendulum is known as bob. Oscillation: 1 complete to and fro motion of the metal bob is known as oscillation. Time Period: Time taken to complete 1 oscillation is known as Time Period. Frequency: Number of oscillations which take place in 1 second is known as frequency. Electric Cell: It is a device which produces electric charge because of some chemical reactions. The cell which is used in a torch is called dry cell. The wet cells are used in car batteries. A normal dry cell gives an output of 1.5 Volt (V). Battery: A group of cells is called battery. More than one cell is used in most of the devices; because these devices need more than 1.5 V of power. Closed Circuit: When the circuit is complete, it is called closed circuit. Current flows only in a closed circuit. Open Circuit: When the circuit is incomplete, it is called open circuit. Current does not flow in an open circuit. Time Period of a pendulum depends on Length of a pendulum. Galileo Galilei found that time period of a pendulum is fixed if the length of a thread is fixed. Stop Watch and Quartz Watch. These watches are very accurate. Stop watches can measure time upto milli seconds. DISTANCE TIME GRAPHS Distance time graph for a uniform motion is a diagonal straight line. Distance time graphs for a non uniform motion is a curve. Distance time graph for a ody at rest is a straight horizontal line parallel to time axis. Heating effect of current When electric current flows through a conducting wire, the temperature of wire increases. This is called heating effect of electric current. Devices Which Work on Heating Effect of Electric Current: Incandescent bulb is an example of a device which works because of the heating effect of electric current. The filament of bulb is made of tungsten. Tungsten has very high melting point and that is the reason it is used in electric bulb. Moreover, argon gas is filled inside the bulb. Argon prevents the filament from catching fire. Electric iron, water heater, geyser, toaster, etc. are some other devices which work on heating effect of electric current. ELECTRIC CURRENT AND ITS EFFECTS CONTINUED.. Elements of Heating Appliances: A heating appliance has a highly coiled wire or a metallic rod. The highly coiled structure increases the surface area and thus provides more heat. The elements are usually made of constantan which is a metal with very high melting point. Electric Fuse: Electric fuse is a safety device which is used in household wirings and in many appliances. Electric fuse has body made of ceramic and two points for attaching the fuse wire. The fuse wire melts whenever there is overload in the wiring. This breaks the circuit and helps in preventing damage to costly appliances and to the wiring. In electrical devices a glass fuse is often used. This is a small glass tube, in which lies the fuse wire. Electric Bell: Electric Bell is composed of two rods of cast iron. Coil is made around the iron rods. A metallic strip is placed parallel to the coils. The metallic strip is fitted with a hammer at one end. Another end of the strip is connected to the circuit. A gong is placed in a position so that it can be hit by the hammer. When current flows in the circuit, the cast iron rods become electromagnet and attract the metallic strip. The metallic hammer hits the gong because of that. Once the metallic strip is pulled towards the electromagnet, it gets disconnected from the point and there is a break in the circuit. A spring pulls the metallic strip back because no magnetism is left in the electromagnet. This cycle continues and the electric bell produces a ringing sound. MCBs (Miniature Circuit Breaker): MCBs have been replacing electric fuse from wirings at most of the places. The electric fuse has a big practical problem. Whenever the wire fuses, one needs to replace the wire to resume electric supply. More often than not, this proves to be a cumbersome task. Miniature circuit breakers break the circuit automatically. One just needs to switch it on to resume the electric supply. Many models of MCBs have a built in mechanism by which the electric supply is automatically resumed. Short Circuit and Overloading: Short Circuit: When live and neutral wire gets connected, current exceed the safety limit and the amount of heat produced increases heavily leading to fire. Overloading: When too many appliances gets connected to a single socket, the amount of current5 exceed the safety limit. It leads to a situation of short circuit. Magnetic Effect of Electric Current: Hans Christian Oersted (1777 – 1851) was the first to show that electric current also produces magnetic effect. He kept a magnetic compass near a current carrying conductor. It was observed that the magnetic compass shows deflection, when the current passes through the conductor. Electromagnet: Magnetic effect of electric current has been used in making powerful electromagnets. For this, wire is wrapped around an iron rod in many turns and electric current is supplied to the wire. As long as the current is supplied the iron rod behaves like a magnet. More number of turns makes more powerful magnet. Electromagnet is used in electric bells and also in powerful cranes. In order to avoid damage due to short circuit and overloading, fuse is used. Fuse is a safety device which melts and break the circuit when current exceeds the safety limit. Fuse is connected in series to the live wire to avoid fire caused due to short circuit and overloading. LIGHT Light travels in a straight line. The ray of light which strikes the surface is called the incident ray. • The ray of light which leaves the surface is called the reflected ray. • A line perpendicular to the surface is imagined at the point of reflection. • The angle between the incident ray and the normal is called the angle of incidence. • The angle between the reflected ray and the normal is called the angle of reflection. Angle of incidence=Angle of reflection The incident ray, reflected ray and the normal all lie on the same plane. These are the Laws of reflection of light. • Reflection:Bouncing back of light when it is incident on the reflecting surface. The ability of mirrors to make left of an object appear right and vice versa is known as lateral inversion. Spherical Mirrors: • CONVEX MIRROR: Image is formed behind the mirror (virtual image) It is right way up( erect) It is smaller in size. CONCAVE MIRROR: Image is formed on the screen when the object is away from the mirror. It is real and inverted When the object is very close to the mirror, image formed is virtual, erect and magnified. • DISPERSION OF LIGHT: Newton had shown that light rays that we obtain from the sun consist of seven different colours – red, orange, yellow, green, blue, indigo and violet. When rays of the sun are made to pass through a glass prism, we will see the seven different colours. Why is an image formed by a plane mirror? An image is formed because light emanates from an object in a variety of directions. Some of this light (which we represent by rays) reaches the mirror and reflects off the mirror according to the law of reflection. Each one of these rays of light can be extended backwards behind the mirror where they will all intersect at a point (the image point). Any person who is positioned along the line of one of these reflected rays can sight along the line and view the image - a representation of the object. Image is formed behind the mirror and that to not by the actual intersection of reflected rays. So, it is a virtual image. It is erect image. It is of the same size as us. It is at the same distance from the mirror as we are from the mirror. A rainbow is seen when the sun appears in the sky after the rains. The moisture in the atmosphere behaves like tiny prisms, dispersing the sun’s rays into seven colours (Vibgyor). The red colour appears on the top of the rainbow and the violet colour appears at the bottom. A Newton disc is a disc with segments in rainbow colours. When the disc is rotated, the colors fade to white; In this way Isaac Newton demonstrated that white light is a combination of the seven different colors found in a rainbow. A Newton Disc can be created by painting a disc with the seven different colors. A combination of red, green and blue in the circular disc will yield the same result. This is due to the phenomenon called persistence of vision. WIND, STORMS AND CYCLONES. 1. What is wind? What is the cause of wind? Moving air is called wind. Air moves from high pressure region to the low pressure region. It is caused due to the difference in air pressure between the two places. Due to the heat of the sun air becomes warm, producing a low pressure. So, the warm air rises up and the cool air from the surrounding moves towards the area. 2. What is cyclone and how is it formed? A. Winds blowing at a speed of 120 km per hour or above are known as cyclone. A cyclone is known by different names in different parts of the world. It is called ‘hurricane’ in the American continent. It is called typhoon in Japan, China and Philippines. In Australia, it is called WillyWillies. Summer Monsoon Winds: In summer near the equator, the land become warm and the temperature of the land increases. The air above the land becomes warm and rises up. This causes the air from the ocean blow towards the land. These are known as Summer Monsoon Winds. Winter Monsoon Winds: In winter, the direction of the wind flow gets reversed. It blows from the land to the oceans. These are known as Winter Monsoon Winds. 5. What is Thunderstorm? Thunderstorms develop in hot, humid tropical areas very frequently. The rising temperature produces strong upward rising winds. These winds carry water droplets upward. At a certain height these tiny water droplets freeze and fall down again. Formation of cyclone: The formation of cyclone is a very complex process. Due to heat of the atmosphere water gets evaporated and changes to water vapour. When water vapour changes back to water due to condensation, the heat is released to atmosphere and warms the air around. Then the hot air rises up causing a drop in pressure. More air from surrounding regions not only rushes in but also starts spiraling. This cycle is repeated. This chain of events ends with the formation of a very low-pressure system with very high speed winds evolving around it. This weather condition called a cyclone. Factors like wind speed, wind direction temperature and humidity contribute to the development of cyclone. 3. What are the different reasons for wind current? A. The different reasons for wind currents are : i) Uneven heating between the equator and the poles due to shape of earth and its inclination. ii) Uneven heating of land and water. Because of their swift movement, the water and ice particles rub against each other and build up a negative electric charge in the cloud. The electric charge is then released by the clouds by the stroke of lightning and thunder is produced. 6. What are the precautions in thunderstorms? A. The precautions in thunderstorms are as below. 1. It is well advised not to take shelter under an isolated tree, because an isolated tree is prone to lightning. While in a forest, it is advised to take shelter under a small tree. 2. Do not lie on ground. 3. Do not take shelter under an umbrella with a metallic rod, as pointed metallic materials are prone to lightning. 4. Do not sit near a window. Open garages, storage sheds, metal sheds are not safe places to take shelter. 5. If one is in water, he should get out and go inside a building. 6. A bus or car is a safe place to take shelter .7. What are tornadoes? A. A tornado is a dark funnel shaped cloud that reaches from the sky to the ground. The neck of the funnel sucks up anything which comes in its way. The tornadoes may form within cyclone. The wind in a violent tornado can circle around at a speed of 300 km per hour. 4. What are monsoon winds? A. The seasonal winds bring rain between June and September in India and South Asia are known as Monsoon winds.There are two types of monsoon winds. They are 1. Summer Monsoon winds ( Sea breeze) 2. Winter Monsoon wind ( Land breeze) 8. What is eye of a storm? A. The centre of a cyclone is a calm area. It is called the eye of the storm. The diameter of the eye varies from 10 to 30 km. It is a region free of clouds and has light winds. 9. Steps taken by government for cyclone warning. A. The steps taken by government for cyclone warning are as under. 1.With the help of Satellite Weather Observation Radars, the formation of cyclone, its direction and intensity is detected by the meteorological department. 2. The news of the formation of cyclone , its direction and intensity etc is immediately telecasted and broadcasted at least 48 hours before the arrival of the cyclone. 3.Cyclone warning is telecasted and broadcasted every hour or half hour. 10. Describe the action on the parts of the people. 1. We should not ignore the warning issued by the meteorological department through television, radio or news papers. 2. We should make necessary arrangement to shift the essential household goods, domestic animals and vehicles etc to safer places. 3.Avoid driving on roads through standing water. 4.Keep ready the phone numbers of all emergency services like police, fie brigade and medical centers. 11. What are the other precautions if you are staying in a cyclone hit are? A. The precautions in a cyclone hit area are as under. 1. Do not drink water that could be contaminated. Always store drinking water for emergency. 2. Do not touch wet switches and fallen power lines. 3. Do not go out just for the sake of fun. 4. Do not pressurize the rescue force by making undue demands. 5. Cooperate and help your neighbours and friends. HEAT. Transfer of heat:Heat is transferred by conduction, convection and radiation. Conduction:Transfer of heat from one particle to the adjacent particle. In solids, heat is transferred by the process of conduction. In this process, the transfer of heat takes place through adjacent molecules. Ex: When one end of an iron rod is put over flame then part which is nearer to the flame is heated first and heat is gradually transferred to the other end of the rod. This happens because particles of iron rod which are nearer to the flame receive the heat and transfers this to the adjacent particles. Subsequently, the adjacent particles transfer the heat to the next adjacent particles. This process continues and heat reaches to the other end of the rod. Thus, heat transfer in solid takes place through conduction. Convection in air: Air gets heated because of convection; the way water gets heated. Air near the source of heat gets heated and rises above. This leaves a gap; which is filled by the colder air from the surrounding. The convection current thus starts in air which results in heating up of air. When you place your palm above a flame you will feel the hotness of the flame. But when you will place your palm below the flame the area will be colder. This shows how the colder air from below moves up; due to convection current. Conductor and Insulator: Materials which allow heat to pass through it are called conductor or good conductor of heat, such as iron, copper, aluminium, etc. All metals are good conductors of heat. Since, mercury is a metal and found in liquid state at room temperature, that’s why it is used in thermometer. Since metals are the good conductor of heat that’s why kitchen utensils are made of metals or alloys of metals. Materials which do not allow heat to pass through them are called bad conductor or poor conductor of heat. They are also called insulators. Example: rubber, wood, plastic, etc. This is the cause that handles of frying pan or other kitchen utensils are made of plastic. Land and Sea Breeze: Sea Breeze: In coastal areas, the breeze that moves from sea surface to the land is called sea breeze. This happens because, during daytime, land gets heated more quickly than water. As a result, warm air from land rises up; leaving a gap. To fill that gap, colder air from the ocean surface rushes towards the land. This phenomenon continues and a continuous flow of cold air keeps coming towards the land. This gives rise to the phenomenon which is called the sea breeze. Because of this, people living in coastal areas prefer to live in a sea facing house. Convection: The transfer of heat because of movement of the molecules of the medium; via mass transfer; is called convection or convection of heat. Water and air are bad conductors of heat. But they do become hot, in spite of being bad conductors. Heat transfer in fluids takes place through convection. Convection in water: When water is heated in a pan, the particles of water which are near the source of heat; get heated first. Because of heating, they become light; and rise in water. The gap which is created because of rise of hot particles is filled cold particles of water from the surrounding area. Thus a cyclical movement of particles begins and ends up heating the whole water of the pan. The cyclical movement in fluids because of heating is called convection current. Land Breeze: In coastal areas, the breeze which moves from land towards the sea is called land breeze. In the night, the land cools down more quickly than the ocean surface. This makes the air over the water surface warmer than air over the land surface. Warmer air over the water surface rises in the air and air from the land rushes towards the water surface to fill the gap. This phenomenon continues which creates a flow of air from land to the sea. This phenomenon is called land breeze. Radiation: All hot bodies emit heat by the process of radiation. Radiation of heat does not require a medium. Sunlight comes to the earth because of radiation as there is no medium present between the atmosphere of the earth and the sun. One can feel the heat of bonfire by standing around it. We get warmth from the room heater because of radiation. Reflection and absorption of heat: When heat falls over an object some of the heat is absorbed by the body and some of the heat is reflected. The temperature of an object increases because of absorption of heat. In conventional room heater you can see the reflector attached with it. The reflector of the room heater reflects the heat towards the person sitting or standing near the room heater. Reflection is the cause that umbrella is used to protect from heat of the sun in summer. Dark color absorbs more heat while light color reflects most of the heat. That’s why wearing light colored clothes is preferred in summer, dark colored clothes are preferred in winter. Dark clothes absorb more heat and keep one comfortable in winter. On the other hand, light clothes reflect most of the heat and keep one comfortable in summer. Heat Heat is the transfer of energy from a hot body. The sense of touch is not reliable and cannot be always used to say how much hot anything is. Thus, hotness of anything is measured in terms of TEMPERATURE in reliable way. To measure temperature a device called THERMOMETER is used. Unit of heat:There are three units which are used to measure the temperature: Degree Celsius, Fahrenheit and Kelvin. Degree Celsius: Degree Celsius is written as °C and read as degree Celsius or simply Celsius. For example 20°C; it is read as twenty degree Celsius. Fahrenheit: Fahrenheit is written as °F and read as degree Fahrenheit. For example 25°F; it is read as twenty five degree Fahrenheit. Kelvin: Kelvin is written as K. For example 100K; it is read as hundred Kelvin. Thermometer: Thermometer is a device which is used to measure temperature Now-a-days many kitchen utensils come in black color, since utensils of black color absorb more heat and thus cooking becomes faster. Woolen Cloth: Woolen clothes are used in winter season. Wool is a poor conductor of heat. In addition to it; air gets trapped in woolen fiber to further increase the poor conductivity of wool. This prevents the radiation of heat of our body to the surrounding and prevents the cold from surrounding to affect our body. Thus, wearing woolen cloth makes one comfortable in winter season. Thermometer is made of a long narrow glass tube; with a bulb at one end. The narrow tube appears as a continuous silver line; because it is filled with mercury. Mercury is a metal which is in liquid state at room temperature and it readily expands or contracts at the slightest change in temperature. Hence, mercury is used in thermometer. Types of thermometer: Laboratory Thermometer: is used to measure the temperature. The scale of temperature is graduated generally from –10°C to 110°C over the glass tube. Each division of temperature scale is further divided into 10 parts to read fraction of temperature. The end of the silvery thread shows the reading of temperature. If mercury lining ends at 37, the reading is 37°C. 4.Wash the bulb end of thermometer with an antiseptic solution. 5.Give two or three jerks slightly. By doing this the mercury level would fall. When it falls to 35°C or below, put it below the tongue and wait for one minute. 6.Take out the thermometer and read the temperature. Temperature would be near 37°C. 7.The normal body temperature is 37°C. This can differ from person to person. Use of Laboratory Thermometer: 1.Take some water in a beaker. 2.Take a laboratory thermometer and 3.Immerse its bulb end in water; holding it vertically. Ensure to dip whole portion of bulb end. The bulb end should not touch the bottom or side of the beaker. 4.Observe the movement of rise of mercury. When it becomes stable, take the reading of the thermometer. 5.Mark the reading when the thermometer is inside the beaker only. Clinical Thermometer: Clinical thermometer is used to measure the body temperature. The scale of temperature is graduated from 35°C to 42°C and or from 94°F to 108°F. The temperature of human body always remains within this range and this is the range on the clinical thermometer. There is a kink make near the bulb of clinical thermometer which prevents the automatic fall of mercury level. Maximum-Minimum Thermometer: Maximum – minimum thermometer is used to measure the daily temperature to prepare weather reports Digital Thermometer: In digital thermometer, reading of temperature is displayed digitally as in digital watches. This is safer because no mercury is used in this. It is important to note that mercury is a highly toxic substance. Precautions while using thermometer: 1.Take a clinical thermometer and hold it horizontally with reading scale towards your eye. 2.Do not hold the thermometer from the bulb. Rotate the thermometer slightly clockwise and anticlockwise. By doing this you will see a shiny thin silvery thread. CHAPTER- GARBAGE IN, GARBAGE OUT Question 1- Why is disposal of garbage an immense problem? Answer- It is an immense problem because of the amount of garbage generated. If it is burnt , it generates smoke and poisonous gases, which pollute the air. If it is thrown into river or the sea, it pollutes the water. If you deposit it on the land, it pollutes the land and also affects the quality of groundwater. SEGREGATING WASTES *The first step in disposal is to segregate the garbage into biodegradable and non biodegradable wastes. *Segregation of wastes is necessary because the two kinds of waste require different methods of disposal. *Segregation has to start from home so every house should have two garbage bins- one for biodegradable wastes and the other for non biodegradable wastes. *In some cities , the municipality provides two different colored dustbins- blue for garbage that can be recycled and the green for biodegradable wastes. RECYCLING BIODEGRADABLE WASTES VERMICOMPOSTING • Biodegradable wastes can also be recycled into compost by another method for composting, using a type of worm called red worm. They look like earthworms. LANDFILL • • A low lying area of landfill is a site of disposal of waste materials by burial and is the oldest form of waste disposal At the landfill, the useful part of the garbage is separated out and the non-useful part is spread on the ground and covered with soil and when the landfill site is completely filled, it is converted into park or a playground REUSING AND RECYCLING PAPER Tear waste paper into small pieces and put them in a blender .Add some water and run the blender to get the paper pulp. Pour the pulp in the tub that already has water in it, and let it stay undisturbed for a few hours. Take out the pulp portion with the help of a wire mesh strainer and let the water drain out. Spread the paste on a wire mesh patting gently to get a uniform layer.Cover with a newspaper and gently pat it dry.Let it dry under sun for e few days. Your recycled paper is ready. You can also add some colour and flower petals to the pulp before spreading and drying to get different kinds of recycled paper. METHOD OF VERMICOMPOSTING Dig a pit about 1 meter in depth. Spread a layer of sand at the bottom. Throw in biodegradable wastes such as plant wastes, paper and coffee and tea remains into it. Sprinkle some water and place a few red worms in it. Cover loosely with grass. The red worms eat the wastes and convert it into compost. Avoid putting wastes that may contain salt, pickles, oil vinegar , meat and milk preparations as food for your red worms, else the disease causing small organisms start growing in the pit. Gently turn over the top layers of the pit every 3-4 days. After about 3-4 weeks the contents of the pit will be completely changed into excellent compost. Now put some waste in the corner of the pit so that most of the red worms shift to this corner. CLASSIFICATION OF WASTE Waste can be classified into two types- biodegradable and non-biodegradable. a) BIODEGRADABLE WASTES- Plants waste such as fruit and vegetable peels, leaves egg shells, paper (paper is made from plants) and animal wastes like bones and meat can be decomposed and mixed with the soil. These are known as biodegradable wastes. Biodegradable waste decomposes very quickly. b) NON BIODEGRADABLE WASTES-Non biodegradable wastes cannot be decomposed or take a very long time to decompose. It includes plastic bags, packaging material, glass bottles, metal containers like cans etc. • RECYCLING BIODEGRADABLE WASTES COMPOST-The nutrients present in biodegradable wastes like fruit and vegetable peels, leaves and farm wastes can be recycled back into the soil by allowing the wastes to decompose in a compost pit. The bacteria and fungi that are present in the soil decompose the wastes and restore the nutrients to yield manure or compost. This method is called composting. • The manure thus obtained is rich in nutrients. • Composting is clean , cheap, safe and it considerably reduces the amount of garbage to be disposed. *Take out the compost from the rest of the pit and dry it in the sun. This can be used as manure in the garden. Red worms do not have teeth but a structure called gizzard which helps them in grinding their food. Powdered egg shells or sea shells could be mixed with the wastes which would help red worms in grinding their food. *This method works in warm and humid conditions as red worms reproduce the best under such conditions and their number can double in a month. Red worms can't survive in very hot or very cold conditions. CHAPTER- NUTRITION IN ANIMALS THE MOUTH THE FOOD PIPE- OESOPHAGUS DIGESTION IN STOMACH • • • • Saliva is a digestive juice that contains an enzyme called amylase. Tongue is a muscular organ that pusges the food towards mouth, helps to mix the food with saliva. The tongue has taste buds present on its surface which help in distinguishing the tastes- sour , salty, sweet and bitter. • • • After the food is swallowed, it slides down the pharynx into the esophagus (food pipe). The esophagus leads from your mouth to the stomach. It is made of muscles which gently push the food down to your stomach in a wave like action called PERISTALSIS. • • • DIGESTION IN THE SMALL INTESTINE • • The mucous protects the lining of the stomach, the acid kills many bacteria that enter along with the food and makes the medium in the stomach acidic helping the digestive juices to act. The digestive juices break down the proteins into simpler substances. The stomach is thick walled, flattened U shaped and the widest part of alimentary canal. It receives food from the food pipe at one pipe and opens in small intestine at the other end. The inner lining of stomach secretes mucous, hydrochloric acid and digestive juices. • • • • • • It is highly coiled and is about 7.5m long. Receives the secretions from the liver and the pancreas .The wall of small intestine also secretes juices. The liver , the largest gland in the body secretes bile juice which helps in the digestion of fats and is stored in a sac called GALL BLADDER. The pancreatic juice acts on carbohydrates , fats and proteins and changes into simpler forms. The intestinal juice completes the digestion of all components of food. The carbohydrates get broken down into simple sugars such as glucose , fats into fatty acids and glycerol and proteins into amino acids ABSORPTION IN THE SMALL INTESTINE • • • • • The digested food is then absorbed by small intestine through thousands of small finger like projections in the inner walls of small intestine known as VILLI. The villi increase the surface area of absorbtion of digested food. Each villus has a network of fine blood capillaries close to the surface. The food absorbed on the surface of villus passes into the blood in the capillaries. The food absorbed into the blood is transported to different parts of the body where it is used to provide energy and materials for growth and repair of body tissues. This is called assimilation. LARGE INTESTINE RUMINANTS • • • • The large intestine is widerand shorter than small intestine about 1.5m long. Its function is to absorb water and some salts from the undigested food. The waste food which is now almost solid is stored in the last part of large intestine called rectum and passed out of the body through the anus .This is called egestion. • • • • • Ruminants are plant or grass eating animals that digest their food in two steps.For ex. Cows, goats, sheep and bison The grass is rich in cellulose and many animals including humans can’t digest cellulose. Food that is swallowed goes into the first chamber called the RUMEN where it is partially digested into cud. It then goes to the second chamber from where it is returned to the mouth for chewing.This process is called RUMINATION and the animals are as ruminants. Ruminants have large sac like structure called rumen between esophagus and small intestine. The cellulose of the food is digested here by the action of bacteria not bacteria not present in humans. FEEDING AND DIGESTION IN AMOEBA • • • • • Amoeba has a cell membrane, a rounded nucleus and many small vacuoles in its cytoplasm. It pushes out one or more finger like projections called pseudopodia or false feet formovement and capture of food. On sensing food it pushes the pseudopodia around the particle and engulfs it and the food becomes trapped in a food vacuole. Digestive juices are secreted into the food vacuole and food is broken down into simpler substances. The undigested food is expelled out by the vacuole. MILK TEETH AND PERMANENT TEETH * The deciduous (also called primary or milk) teeth is the first ones to appear and they are fully formed by age of 3. The complete deciduous (because they fall like leaves of deciduous tree) teeth is 20. At age of 6 the first permanent teeth appear by displacing their predecessors. * The complete permanent teeth is 32.Permanent teeth are stronger than the milk teeth. Wisdom tooth appears between ages of 17-21, although not everyone gets it. They are called wisdom teeth because they appear when we grow older and supposedly wiser. TYPES OF TEETH The Incisors (8 incisors are the very front human teeth) are the teeth in the very front. They're the sharpest teeth, built to cut food and shaped to shovel the food inward. The Canine (4 canine teeth) teeth are in the corners of your mouth. Because they're meant for grasping and tearing food, they have very long roots. HUMAN TEETH • The human tooth has two primary components:the crown and root. The crown is the portion of the tooth that projects above the gums while the root is that portion that anchors the tooth to the bone. The enamel covers the crown of the teeth and is the hardest known substance in the human body. STEPS INVOLVED IN NUTRITION The various processes involved in nutrition, in animals that take solid food are as follows: 1 Ingestion: The process of taking in food through the mouth is known as ingestion. 2 Digestion: It is the process of breaking down food- physically and chemically – into simple and soluble form. 3 Absorption: The process of absorption takes place in the small intestine. Here, the digested food is absorbed in the blood through the villi, which are sac-like structures. • • INTRODUCTION Animal nutrition includes nutrient requirement, mode of intake and its utilization in the body. The components of food are complex substances which need to be broken down into simpler substances. The breakdown of complex components of food into simpler substances is called digestion. HUMAN DIGESTIVE SYSTEM • • The alimentary canal of digestive tract is divided into various compartments 1) Buccal cavity 2) food pipe or oesophagus 3) stomach 4) small intestine 5) large intestine ending in rectum and 6) anus The inner wall of stomach and small intestine and various glands associated with the canal such as salivary glands, liver, gall bladder and pancreas are the organs that secrete digestive juices that help convert complex substances in food into simpler substances. • • TYPES OF TEETH Premolars (8 premolars) are located just behind your Canine teeth. Premolars have a more flat chewing surface because they're meant for crushing food. The Molars (12 molars are the back human teeth) are the last teeth towards the back of your mouth. Molars are much bigger than the Premolars and have bigger, flatter chewing surfaces because their job is to chew and grind the food into smaller pieces. .DIFFERENT WAYS OF TAKING FOOD • • • • • Bees and humming birds suck the nectar of plants Infants of human and many other animals feed on mother’s milk. Snakes like python swallow the animals they prey upon Some aquatic animals filter the food particles floating nearby and feed upon them. Digestive juices are also secreted by the inner walls of the stomach and small intestine. THE MOUTH • The process of taking in food is called ingestion. • The food is taken in is chewed and broken into smaller pieces mechanically with the help of teeth present in the mouth. The process of breaking down the food physically is called mastication. • The saliva in the mouth secreted by salivary glands helps to breakdown starch of the food into sugars CHAPTER- NUTRITION IN PLANTS OTHER MODES OF NUTRITION Depending on the mode of nutrition of heterotrophs, all the heterotrophic plants can be divided into: a) PARASITIC PLANTS • A parasitic plant is the one that derives some or all of its nutrition from another plant. • The plant from which it obtains nutrition is called the host. • Since they deprive the host of its valuable nutrients, it is called a parasite. • For ex Cuscuta or Amarbel a plant parasite and lice, leeches and mosquitoes (which suck our blood) are also parasites. SAPROTROPHS • Saprotrophs are organisms like fungi and bacteria that grow and feed on dead plants or animals. They do not have chlorophyll, hence can’t perform photosynthesis. Because of the lack of chlorophyll, these organisms can either be colorless or can come in variety of colors. They secrete digestive juices on dead and decaying matter and convert it into a solution and then absorb the nutrients from this solution. • • INSECTIVOROUS PLANTS • • • In some places, where soil is deficient in nutrients especially in nitrogen, the plants feed on insects to obtain nutrition. Such plants are called as insectivorous plants. Some common examples of insectivorous plants (carnivorous plants) are: Pitcher plant, Venus fly trap ad Bladderwort. Insectivorous plants feed on insects to obtain the nitrogen compounds needed for their growth, hence are “partial heterotrophs” as they get some food by photosynthesis and some by eating insects. FUNGI CAN BE USEFUL AS WELL AS HARMFUL • • • SYMBIOTIC PLANTS • • • • Some organisms live together and share shelter and nutrients. This relationship is called symbiotic relationship. For ex. In lichens, a chlorophyll containing partner, which is an ‘alga’ and a non-green plant ‘fungus’ (Saprotrophs) live together. This fungus provides shelter, water and minerals to the alga and alga provides food which it prepares by photosynthesis Another example of symbiotic relationship is provided by Rhizobium bacteria and leguminous plants. For ex. Fungi such as mushrooms and yeast are useful as mushroom can be eaten as vegetable whereas yeast is used to produce alcohol. Some fungi are also used for making medicines. For ex. Penicillium fungus is used in making antibiotic called penicillin. Fungi can also cause diseases in plants and human beings. The skin disease (called ringworm) in humans is cause by fungus. NITROGEN FIXATION BY RHIZOBIUM • • • • Crops require good supply of nitrogen in the soil which after a harvest become deficient in nitrogen. Nitrogen is abundant in the atmosphere , but the plants cannot take it directly from the atmosphere. Plants used nitrogen in soluble form so the bacterium Rhizobium can take atmospheric nitrogen and convert it into a soluble form. Rhizobium , which cannot make its own food, gets food and shelter from the leguminous plants like it lives in the roots of gram, peas moong etc. NUTRIENTS- Components of food like carbohydrates, proteins, fats, vitamins and minerals that are necessary for our body are called nutrients. NUTRITION -the process of taking in food by an organism and its utilization by body is called nutrition. MODES OF NUTRITION IN PLANTS • The mode of nutrition in which organisms make food themselves from simple substances is called autotrophic nutrition. Such plants are called autotrophs. HETEROTROPHIC NUTRITION • Those organisms which cannot make food themselves by the process of photosynthesis and take food from green plants or animals, are called heterotrophs and their mode is heterotrophic mode of nutrition. PHOTOSYNTHESIS • • • AUTOTROPHIC NUTRITION A chemical reaction takes place in the leaves of plants as these raw materials carbon dioxide and water react. • Carbon dioxide from air is taken in through the tiny pores called stomata present on the surface of leaves. • • SECTION THORUGH LEAF Each stomata are surrounded by two crescent shaped guard cells. The products of the reaction are glucose and oxygen. The carbohydrate ultimately gets converted into starch and oxygen is released. LEAVES OF VARIOUS COLOURS • The leaves having colors other than green also have chlorophyll in them .Actually, the large amount of red, violet, brown or other pigments in such leaves masks the green color of chlorophyll. So, photosynthesis also takes place in leaves of othercolors such as red, violet, brown, etc. • PHOTOSYNTHESIS Green plants have the unique ability of trapping the solar energy and converting it to chemical energy which is stored in the food. This process is called photosynthesis. Green plants can make their own food from raw materials like carbon dioxide and water in the presence of chlorophyll (a green pigment present in the leaves) and sunlight. Hence we can say that chlorophyll, sunlight, carbon dioxide and water are necessary to carry out photosynthesis. The process of photosynthesis can be represented by a word equation as follows: Carbon dioxide+ Water Glucose + Oxygen (from air) (from soil) (a carbohydrate) (Goes to air) • • • Algae are a large group of simple, plantlike organisms that contain chlorophyll and produce food by photosynthesis just like plants. Algae however differ from plants because they do not have proper roots, stems and leaves. The green color of algae is due to the presence of chlorophyll in them. CHAPTER- THE LIVING ORGANISMS AND ITS SURROUNDINGSCLASS VI HABITAT AND ADAPTATION • Are suited to the place where they live. The body features of all organisms. • The sea and desert are very different surroundings and different kinds of plants and animals are found in these two regions. • For ex. The body structure of a camel helps it to survive in desert conditions like: i) Camels have long legs which help to keep their bodies away from the heat of the sand. ii) They excrete small amount of urine, their dung is also dry and they do not sweat. iii) I t has padded hoofs to enable it to walk on sand. • • HABITAT AND ADAPTATION All living beings, plants and animals are called organisms. The process of specific features or certain habits of an organism which help it to survive in its surroundings are called ADAPTATION. All organisms need a place to live where they can get plenty of food, shelter and protection from enemies and adverse conditions. The area or surroundings in which an organism lives is called its HABITAT. FIXED – The flowers, leaves and roots of these plants float on water but their stems remains fixed to a place. The roots are poorly developed. For ex water lilly and lotus. The stem of lotus is very long, thin and has air canals in it. The petals and leaves have a waxy coating on them to prevent from rotting. c) SUBMERGED- Some plants like hydrilla, vallisnaria remain submerged in water. Some of these plants have narrow ribbon like leaves which can bend in water. In some submerged plants the leaves are needle shaped through which the water can easily flow without damaging them. HABITAT AND ADAPTATION The body structure of a fish helps it to survive in sea conditions like: For ex. A fish has a streamlined body which helps it to cut through water and move forward. It has fins to change its direction. It has gills which help it to absorb the dissolved oxygen in water. A turtle has a soft body which can hide inside its exoskeleton. It can live both on land and water. It has a tall which helps it to swim. COMPONENTS OF A HABITAT A habitat has two components-Biotic and Abiotic. a) BIOTIC COMPONENTS- plants and animals present in a habitat. b) ABIOTIC COMPONENTS- The non-living components of a habitat lime the rocks, soil, air, water, sunlight and temperature etc. are called abiotic components of the habitat. FEATURES OF AQUATIC HABITATS Aquatic plants and animals are the ones which live in water.OCEANS• Some sea animals like squids and Octopus lives in the depths of oceans and doesn’t have a streamlined shape. They stay deeper in the ocean, near the seabed and catch any prey that moves towards them. However when they move in water they make their body streamlined. • These use the oxygen dissolved in water through their gills. Some animals like dolphins and whales that do not have gills. They breathe in air through nostrils or BLOWHOLES that are located on the upper parts of their heads. SOME AQUATIC HABITATS ii) PONDS AND LAKES In terrestrial plants, roots normally play a very important role in the absorption of nutrients and water from the soil. However In aquatic plants, roots are much reduced in size and their main function is to hold the plant in place. The stems of these plants are long, hollow and light. FLOATING- These do not have well developed roots and float with the current of water. Their flowers and leaves remain above water. For ex. Duckweed. i) DESERTSThere are desert animals like rats and snakes ,which do not have long legs like camel and to stay away from the heat they stay in burrows during day and come out in night. Their eyes are also adapted to see at night. Desert plants like cactus lose very little water through transpiration. The leaves in these plants are either absent, very small, or they are present in the shape of spines which help in reducing transpiration. The leaf-like structure in cactus is its stem which helps in carrying out PHOTOSYNTHESIS. The stem is also covered with a thick waxy layer, which helps to retain water Most desert plants have roots that go very deep in the soil for absorbing water. MOUNTAIN REGIONS The trees in mountain regions are normally cone shaped and have sloping branches. The leaves of some trees are needle like which helps the rainwater and snow to slide off easily. Animals like YAKS,have long hair to keep them warm. Snow leopard has thick fur on its body including feet and toes which protects them from cold when they walk on snow. The mountain goat has strong hooves for running up the rocky slopes of the mountains. iii) GRASSLANDS Lions have long claws in the front of their legs that can be withdrawn inside the toes. Its light brown colour helps it to hide in dry grasslands when it hunts for PREY(animals to eat). The eyes in the front of the face allow it to have a correct idea about the location of its prey. A deer is another animal that lives on forests a nd grasslands and has strong teeth for chewing hard plant stems of forest. A deer has long ears to hear the movements of predators(the animals which hunts other animals for food). The eyes of deer are on its side of its head which allow it to look in all directions for danger. LIVING BEINGS AND THEIR CHARACTERISTICS *Some animals may have different mechanism for the exchange of gases , which is a part of respiration process. For ex. Earthworms breathe through their skin. Fishes have gills to use oxygen dissolvedin water. *Exchange of gases in plants mainly takes place through their leaves that have tiny pores in them and use oxygen and give out carbon dioxide to the air. *Plants produce their food only during daytime whereas respiration takes place day and night. *The amount of oxygen released in the process of food preparation by plants is much more than the oxygen they use in respiration. ADAPTATION AND ACCLIMATISATION If we go to high mountains, we feel breathlessness for some time due to lack of oxygen in the air and soon our body adjusts itself and we become normal. These small and temporary changes in the body which make an organism better suited to its changed surrounding are called ACCILIMATISATION which are different from ADAPTATION. All living beings show response to stimuli • The change in the environment of an organism is called STIMULUS and the reaction of that organism to the stimulus is called RESPONSE. For ex. If we accidently touch a very hot object, our hand is withdrawn immediately .Here the hotness is the stimulus and our action is the response. • Many plants such as sunflower bends towards sunlight. • Some flowers bloom only at night. • Some plants like mimosa leaves close or fold when someone touches it. • These are all responses of plants to external conditions. LIVING BEINGS AND THEIR CHARACTERISTICS *All living things need food. *All living things show growth. *All livings respire- Respiration is the process through which the body obtains energy from the food it takes. The two main processes of respiration are: i) EXTERNAL RESPIRATION or BREATHING- taking in air rich in oxygen(inhalation) and giving out air rich in carbon dioxide(exhalation). ii) INTERNAL RESPIRATION or CELLULAR RESPIRATION- Using oxygen to break down food to release energy. It occurs in body cells. In respiration, glucose molecules react with oxygen and break down into carbon dioxide and water to release energy. C6H12O6+6O2 6CO2 + 6H2O+Energy All living beings excrete- The throwing away of unwanted or harmful wastes products from the body is called excretion. f) All living beings reproduce- Some animals like fish, birds, snakes etc. lays eggs. These are also called as Oviparous animals. • Some give birth to their young ones like human beings , cat, dogs etc. These are also called as Viviparous animals. • Plants reproduce by different methods ,either through seeds or through parts other than seeds. • VEGETATIVE PROPAGATION- It is a type of reproduction in which new plants are produced from the vegetative parts of a plant like roots, stem, buds and leaves. CHEMISTRY Process to obtain wool from sheep: Steps given below are followed to obtain wool from sheep or other wool bearing animals Step 1 – Shearing - The fleece (hair) of sheep is shaved off along with a thin layer of skin. In olden days this was done using pair of metal blades. But now-a-days machine is used to cut off the fleece. This is similar to shaving of beards or hair. This process is called shearing. Shearing is done generally in summer so that sheep could get new hair by winter to get protection against cold. Step -2 – Scouring – Fleece, after shearing, is washed properly to remove dirt and grease. The washing of fleece; after shearing; is called scouring. Step- 3 – Sorting – After scouring, fleece are sorted according to texture. This process is called sorting. Types of Silk: Different types of silk worm produce different types of silk; in terms of luster and texture. For example; tassar silk, mooga silk, kosa silk, etc. are produced by different types of silk moth. Mulberry silk is the most common silk moth. Rearing of silkworm: Rearing of silkworm is known as SERICULTURE. Silkworms are reared on mulberry leaves as they feed on mulberry leaves. Life cycle of silkworm: Female silk moth → Lays eggs → After about 14 days eggs are hatched into larva → Grown into Pupa →Weave a net and enclosed itself → Produce liquid protein from its salivary glands moving it’s head in the shape of ‘8’ forming cocoon→ Live in the cocoon for some time → After coming out of cocoon grows into silk moth . • Nylon is the first fully synthetic fibre made by man without using any natural raw materials (pNylon is the first fully synthetic fibre made by man without using any natural raw materials (plants and animals). • It was prepared from coal, water and air. • Nylon polymer is a polyamide - a polymer that is made up of 2 different monomers, a diamine and a dicarboxylic acid, combined alternately to form long chains. • Nylon fibres are very strong, fairly elastic , lightweight and lusturous and easy to wash. lants and animals). • • • Rayon is a semi synthetic fibre because although it is obtained from a natural resource called wood pulp(polymeRayon is a semi synthetic fibre because although it is obtainedRayon is a semi synthetic fibre because although it is obtained from a natural resource called wood pulp(polymer cellulose), yet it is a man made fibre because it is obtained by chemical treatment of wood pulp in factories. Rayon is chemically identical to cotton but it has shine like silk. as artificial silk. Step – 4 – After sorting, fluffy fibers; called burr; are picked out from hair. Burr is the fiber that gives wool. Step 5 – Dying – After sorting and picking out of burrs, these are dyed in desired colors. Step 6 – Spinning – The fibers are then straightened, combed and rolled into yarns. Wool yarn is used in knitting sweaters and woolen cloths, i.e. fabric Silk moth to silk: After they are laid by the silk moth; eggs are stored over a clean cloth or paper strips. When larvae are hatched from eggs, they are kept in clean bamboo trays with fresh leaves of mulberry. Larvae feed on mulberry leaves for about 20 to 25 days. After that, larvae move into tiny chambers of bamboo in which they start spinning cocoon. They do it by secreting liquid protein from their salivary glands. Finally they enclose themselves in cocoon. Cocoons get hardened because of exposure to air. Obtaining of silk from cocoon: First of all, cocoons are boiled and then silk fiber is separated out; using machines. Machine unwinds the silk thread from cocoons. The process by which silk fiber is obtained is called REELING THE SILK. Silk thread so obtained is woven into different types of cloths, i.e. fiber. • • • • • • Polyester(poly+Polyester(poly+ester) is another synthetic fibre which contain many ester groups. Esters are the organic chemical substances which give fruits their sweet smell. Terylene is a popular polyester fibre. Most of the properties of polyester fibres (like terylene)are similar to those of nylon. Polyester fibres are , however stronger than nylon fibres Polyester fabric is strong ,wrinkle resistant , easy to wash and dry. ester) is another synthetic fibre which FOOD Food Importance of food • Food provides energy. • Food is needed for growth. • Food helps in maintaining good health. • Food maintains body functions. • Food is necessary to heal wounds. Edible parts of the plant a) Roots: carrot, turnip, radish and beetroot. b) Stem: sugarcane, potato, ginger. c) Leaves: sources of calcium. spinach, cabbage, Amaranthus, curry and Onion leaves etc. d) Flowers: pumpkin, banana, cauliflower. e) Fruits: fleshy or dry e.g. mango, guava, orange, apple, pear, grapes, banana , almonds, cashew nut brinjal, tomato, lady's finger, beans, bottle guard, snake gourd, bitter gourd . Components of Food Nutrients are nourishing components of food that are required by our body. Energy-giving food :They release energy and help in body growth.: Carbohydrates and fats Body-building food: Proteins they help in body growth and repair of damaged parts of the body. Protective food: Vitamins and minerals they protect us from many dieases. They give us resistance against disease causing germs. 1) Carbohydrates: sugar, starch and cellulose. Sugar is sweet. Glucose is the instant sugar. Fructose fruit sugar. Common sugar sucrose Lactose milk sugar. Starch in grains like rice, wheat, maize, tubers like potatoes etc. Cellulose cannot be digested by human beings f) Seeds: Grains., pulses and oil seeds. Grains include rice, wheat, jowar, maize, ragi etc. Pulses include grams, peas, beans etc. Oil seeds include groundnut, sesame, mustard, coconut, sunflower seed etc. Poultry farm is the place used to rear birds for their eggs and meat. Dairy farm is the place where buffaloes, goats, cows, sheep, pigs etc are kept in shed for rearing. We rear animals for their milk and meat. Milk is also used to prepare dairy products. Aquaculture includes rearing of fish, crabs, lobsters etc. Fish provide their meat for us. Fish can be marine or freshwater fish. . Animals and their food:Based on food they eat a) Herbivores: Animals which eat only plants(grasseating animals) e.g. Cow, sheep, goat, deer, buffalo. 2)Proteins: Proteins help in healing of wounds. Proteins also help in repair of damaged parts in the body. 3) Fats: Fats are energy-giving food. They provide us with more energy From Animal: milk, butter, ghee, cheese and meat. From plants ( oils).Seeds like mustard, sesame, groundnut, soyabean, coconut, sunflower, safflower 4)Vitamins& minerals: Protect our body from diseases. Green vegetables &leafy vegetables, beans, pulses whole grains, unpolished rice . 5) Water: It protects us from dehydration, easy passage of food. It dissolves many substances in it, forms the liquid medium of blood ,acts as main transport channel throughout the body. .b) Carnivores: Animals which eat only small animals (flesh-eating animals) e.g. Tiger, lion, jackals, vultures etc. c) Omnivores: Animals which eat both plants and animals . e.g. Human being, bear, crow etc. d) Decomposers: Organisms which feed on dead plants, dead animals and rotten materials and decompose for their food .Bacteria and Fungi e)Scavengers: Organisms which feed on dead animals . e.g. Vulture 6) Dietary fibres:(roughage) easy digestion of food, they provide us bulkiness in the stomach. Test to confirm the presence of 1)carbohydrate (starch)-Iodine Test (Blue black colour confirms the presence) 2)Proteins-copper sulphate and caustic soda (Violet colour confirms the presence) 3)Fats-An oily patch on the paper indicates the presence of fat. Deficiency Diseases:1)Protein Energy Malnutrition (PEM)-Kwashiorkor and Marasmus 2) Iron deficiency: Anaemia. 3) Iodine deficiency: Goitre 4) Vitamin A: Night blindness 5)Vitamin B1: beriberi. 6) Vitamin C: scurvy 7) Vitamin D: rickets Getting to know Plants Based on the size, nature of the stem and the life span, plants are classified into herbs, shrubs, trees, creepers and climbers. a) A herb: non-woody plant that has green and tender stem with few branches on it &has a very short life,. Mustard, Tulsi, Wheat, Gram b)A shrub is taller than a herb and has stem branching out at its base, bushy plant. The stems are not hard but thick. Sunflower, Rose, Lime c) A tree is a woody plant that has many branches on a single stem. Mango , Neem , Peepal tree d) Creepers are the plants with weak stems and hence cannot stand straight. Depending on the presence of flowers, a) Flowering e.g. Mango, Papaya, Guava. b) Non-floweringe.g. Fern, Moss. Depending on the way they obtain food a) Autotrophs . e.g. Most of the green plants. b)Heterotrophs e.g. Insectivorous plants Parts of a plant:Root: Underground and look brown in colour. The tiny thread-like structures over the roots are the root hairs. The tip of the root is covered by root cap which is preventive in function. Root and the root hairs form the root system Modifications of roots. 1.Storage roots: Carrot, turnip, radish etc 2.Respiratory : pneumatphores(Mangrooves) 3.Parasitic roots . e.g.Cuscuta. 4.Climbing roots . e.g. Money plant, betel. 5.Reproductive roots 6.Prop roots :. Banyan tree Types of rootsRoots are of two types - tap root and fibrous roots. 2)Stem :seen above the ground. It bears the leaves, flowers and fruits of a plant. Modifications of stem. 1.Storage of food: are tubers (e.g. Potato), rhizome (e.g.Ginger) and bulb (e.g.Onion). Body Movement Locomotion is brought about by the combination of muscular and skeletal system. The bending and movement of the skeleton is brought about by special structures called as joints. Joints Joint is a point at which two separate bones meet. Joints are held at position by strong cords called as ligaments. a) Fixed or immovable joints :sutures between the bones of the cranium,ribs in the breast bone, bones of the hip girdle. b) Slightly movable joints :joints of the lower jaw c) Freely movable.1)Ball and socket joint: Shoulder joints and hip joints. 2)Pivot joint: joint which joins the neck to the head. 3)Hinge joint: the elbow joint and the knee joint. 4)Gliding joints: ankles,wrist & between vertebrae. Movement in bones:Joints along with muscles can bring about movement in bones. Skeleton:is an internal framework of all the bones and cartilage in the human body. Bone is a type of fibrous connective tissue. Bones also anchor the muscles. Cartilage is a soft elastic tissue that covers the bones at the region of the joints. Types of bones a)Round and long: in limbs. b)Ring like bones with outgrowths: vertebrae Flat and strong: skull c)Girdles: shoulder region and pelvic region. Parts of skeleton a)Axial skeleton includes the skull, vertebral column and the rib cage. b)Appendicular skeleton includes shoulder bone, pelvic bone, arm bone, and the leg bone. 2.Photosynthesis: In some desert plants, 3.Protective structures: rose, Supportive structures: In climbing plants, 4.Storage of water: cactus and jade 3) Leaves have chloroplasts which have chlorophyll in them. Parts of leaf: leaf base., petiole, lamina.,mid-vein. veinlets. Veins help in transportation of food and water. parallel venation and reticulate venation Types of leaves1):Simple 2)Compound Arrangement of leaves. Arrangement can be alternate,opposite, whorl etc. Functions of leaf 1)photosynthesis 2)transpiration Modifications of leaf a) tendrils b) store food c)insectivorous plants, 4)Flower:reproductive structure 5)Fruit: Fruit is basically the fertilised ovary. 1.Gait of earthworms:Earthworm is a small annelidan .Possesses setae which help in their movement. Earthworms move forward by repeated contractions and relaxations of their muscles in the skin.A slimy substance secreted by the earthworm helps in its movement. 2.Gait of cockroaches:Cockroach is an arthropod with six jointed legs which help it to walk, and two pairs of wings help it to fly. 3.Gait of snails:Snail is a small molluscan with thick exoskeleton.Single muscular foot for locomotion. 4)Gait of fish:Fish vertebrate with vertebral column in its body. possess a streamlined body, fins,.tail flaps which help them swim 5)Gait of snakes: vertebrates with vertebral column. Have long back bone & many interconnected muscles that help them to slither. 6)Gait of birds: arboreal in habit. They fly in the air(wings). They can also walk. Birds have light and hollow bones.