Science 5. Piyush Ganeshiya HOLY FAITH INTERNATIONAL (P) LTD. M.Sc. Chemistry, B.Ed. PGT (DPS Sonepat)

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2 Science 5 Piyush Ganeshiya M.Sc. Chemistry, B.Ed. PGT (DPS Sonepat) HOLY FAITH INTERNATIONAL (P) LTD.

3 Preface The Hummingbird series of Primary Books from I to V are based on National Curriculum Framework (NCF) 2005 and the new Syllabi for classes at the Elementary Level. In the guidelines some of the objectives of teaching the different subjects at primary stage are: to train children to locate and comprehend relationships between the natural, social and cultural environment; to nurture the curiosity and creativity of the child particularly in relation to the natural environment; to develop an awareness about environmental issues; to engage the child in exploratory and hands-on activities. The Hummingbird series focus on themes that allow for a connected and interrelated understanding, to develop and trigger the child s thinking in new directions. They connect knowledge to the child s life outside the classroom and also provide an overall development of children. The series comprises of textbooks on: MATHEMATICS Children need to develop a positive attitude towards and a liking for Mathematics at the primary stage, along with the cognitive skills and concepts that they acquire. The content includes Mathematical games, puzzles and stories that help in making connections between Mathematics and everyday thinking. ENGLISH An integrated approach to the teaching of language is of particular relevance at the primary level. The books address different skills of language, namely listening, speaking, reading and writing, which focus on across the curriculum approach through a variety of genres poems, stories, role-plays and drama to develop the language skills creatively. SCIENCE Science education should develop competence and encourage inventiveness and creativity. The textbooks incorporate activities, observation, experimentation and encourage an active approach to science, connecting it to the world around the child, rather than information based learning. SOCIAL SCIENCE The textbooks provide the social, cultural and analytical skills required to adjust to an increasingly interdependent world. The focus of the books is on a conceptual understanding rather than lining up facts to be memorized. ENVIRONMENTAL STUDIES Environmental Studies is a subject dealing with Man s relation to his whole environment, viz. his surroundings, his home, his neighbourhood, his city or town, extending ever outward. The books contextualize the relevance of the subject and bring it to life. The textbooks present the subjects in a clear, concise, logical and chronological manner. It is expected that this new series will inspire the children to analyse, demonstrate and transform their world view.

4 CONTENTS UNIT-I 1. Plants Reproduction Animal World UNIT-II 3. Skeletal and Muscular System Nervous System Nutrition and Diseases Safety and First Aid 56-66

5 UNIT-III 7. Rocks and Minerals Simple Machines UNIT-IV 9. Our Environment Natural Calamities UNIT-V 11. Air and Water The Moon and Shadow

6 Unit I 1 Plants Reproduction Learning Objectives Reproduction in plants Types of reproduction Parts of a flower Pollination Growing of plants from seeds Dispersal of seeds Crops protection and storage of seeds Plants are very useful to us. They are the only living beings which make their own food and provide food for all other living beings. Plants also give out oxygen which all human beings and animals need for breathing. Plants also check soil erosion. They are, therefore, called our green friends. Hence, it is necessary to grow more and more plants on earth. REPRODUCTION IN PLANTS Living things do not live forever. They all die but life continues due to the process of reproduction. Like animals, plants also reproduce. Plants produce new plants like themselves. This process of production of new plants is called reproduction. TYPES OF REPRODUCTION Plants reproduce by the following methods: 1. Asexual reproduction 2. Sexual reproduction Asexual reproduction Asexual reproduction is a mode of reproduction by which offspring arise from a single parent and inherit the character of that parent only. These offsprings are the exact copies of the parent plant. Vegetative propagation The kind of reproduction in which a new plant grows from the body parts of a plant such as the stem, roots and leaves is called vegetative propagation. Vegetative propagation by roots A new plant can also grow from the roots of the mother plant. Sweet potato, carrot, radish, turnip and dahlia are some examples of plants whose roots can grow into Plants Reproduction 1

7 new plants. Some plants like gladioli, lilies and tuberoses grow from the bulbs of the mother plants. The bulbs are underground buds. These are called bulbs because these are shaped like bulbs. Sweet potato Radish ACTIVITY To study the process of reproduction by roots. Materials required: Carrot, shallow dish and water. Procedure: Cut off the top portion of a carrot that has leaves. Place it in a shallow dish with the cut end facing downwards. Pour water into the dish such that half of the cut carrot is dipped in water. Keep this in a place where it will receive enough sunlight. Observe after a few days. Observation: You will see that after a few days, a new plant has grown on the top portion of the carrot. Vegetative propagation by stem Reproduction by roots Some plants like rose, hibiscus, money plant and sugarcane can grow from the stems of old plants. A piece of stem having buds is taken from the mother plant and is planted in the soil. After a few days, new plants grow out from the buds. This method is called stem cutting. Potato Ginger Onion The potato is a stem that grows underground and has buds called eyes. Any part of 2 Plants Reproduction

8 a potato that has buds, when planted in the soil, can grow into a new plant. Onion and ginger are also underground stems from which new plants grow. Some plants grow by layering Some plants can also be grown by layering. In this method, the side branches are bent towards the ground and covered with moist soil, keeping the tip free. After a few days, new roots develop. Jasmine plant and lemon plant reproduce by the process of layering. Growing of grass We know that grass plants creep along the ground like a green carpet. Side branches grow out of creeping stems. They separate and grow into new plants. These are called runners. Mango, grapes,rose and many other fruit plants are grown by stem cutting and budding. Growing grass Layering Stem cutting Vegetative propagation by leaves Leaves of certain plants produce buds along their margins. New plants grow from these buds if the leaves are placed in moist soil. For example, bryophyllum leaves. New plant from bud Buds in bryophyllum leaf Spores of fungus Plants Reproduction 3

9 Vegetative propagation by spores Certain plants do not bear flowers and seeds. They have special structures called spores which help in reproduction. For example, mushrooms, ferns and mosses. If you rub many dark coloured dots lying underside of a fern plant between your thumb and forefinger, the powdery substance you can feel between your fingers are the spores. Sexual reproduction Sexual reproduction is the method of reproduction in plants by which offsprings produce from a male and a female parent. The offspring will inherit the traits of both the parents. Flowers are the reproductive organs of plants. They turn into fruits, which have seeds inside them. New plants grow from seeds. Anther Filament Ovule Pedicel Stigma Style Petal Sepal PARTS OF A FLOWER A flower has the following four parts: 1. Calyx 2. Corolla 3. Androecium 4. Gynoecium Each of these parts are arranged in a whorl on the base of the flower. 1. Calyx It is the outermost whorl consisting of units called sepals. Sepals are green leaf-like structure at the base of a flower and enclose the rest of the flower in the bud stage. 2. Corolla Corolla is the next whorl towards the apex. Corolla is composed of units called petals. Parts of a flower GO FACT Dahlia is named after Anders Dahl, a botanist of the 18th century. The petals are soft, brightly coloured and the most beautiful parts of the flower. They attract insects, which help in pollination. 3. Androecium It is the male reproductive whorl consisting of units called stamens. The stamen is made up of filaments which have a swollen head at the top called the anther. The anther contains a yellow powder-like substance called the pollen grains. 4 Plants Reproduction

10 4. Gynoecium Gynoecium is the innermost whorl of a flower, consisting of one or more units called the carpel. Carpel is the female part of a flower that consists of a long tube called the style. At the bottom of the style, a swollen base called ovary is present. Inside the ovary, ovules are present. The uppermost part of the style is called stigma. ACTIVITY Parts of flowers Take a big flower like China rose. Observe its petals, sepals, stamens and carpel. Separate these parts and paste them in your scrapbook. POLLINATION The transfer of pollen grains from the anther to the stigma of a flower is called pollination. Birds and insects get attracted towards colourful flowers. Insects feed on the nectar from the flower, the pollen grains from the anther stick to their bodies. When the insects move to the stigma of a similar flower, the pollen grain falls on the stigma and pollination is carried out. After sometime, a tube known as the pollen tube comes out of a pollen grain and reaches the ovary through the style. When the pollen tube reaches the ovary, fertilisation takes place. After fertilisation, the ovary of the flower grows into a fruit and the ovule develop into seeds. Pollination GROWING OF PLANTS FROM SEEDS Most plants grow from seeds. Seeds are obtained from flowers and fruits. A plant produces many seeds. But all of them do not get a chance to grow into new plants. Why do all the seeds not grow into a new plant? Some of the seeds are not fully grown and developed when they are separated from their parent plants. Some of these are destroyed by strong winds and heavy rains. Plants Reproduction 5

11 Some of the seeds are destroyed by insects and other animals during storage. Even when the seeds have been sown in the soil, some of them do not survive because they do not get proper soil and sufficient water and air. Some of these may be eaten up by birds, rats and other animals. Seed and its parts A seed is a tiny life-supporting package which can give rise to a tree. It contains the embryo or a baby plant and stored food. A seed has mainly three parts the seed coat, seed leaves and embryo. Seed coat: It is the outer covering which protects the baby plant inside the seed. It has a tiny hole through which the seed gets water. Seed leaves: When you peel away the seed coat, you will see two seed leaves or cotyledons. They contain the stored food which is used by the growing seedling. Some seeds have two cotyledons. Such seeds are called dicotyledons. For example, gram, pea and bean seeds. Some seeds like maize, wheat and rice have only one cotyledon and are called monocotyledons. Baby plant or embryo: The embryo is a baby plant which lives between the seed leaves. The embryo contains two parts the radicle and the plumule. The radicle develops into the root and the plumule into the stem. Baby plant Seed coat Cotyledons Structure of seed Germination of seeds The development of a seed into a seedling is called germination. When the seed is sown in the wet soil, it absorbs water. On absorbing water, the seed coat becomes soft and breaks, from which a small root called radicle (sprout) emerges. This radicle grows downward and becomes the root of the plant. This is followed by the growth of a plumule a small shoot. The plumule grows upwards and produces the stem and leaves. 6 Plants Reproduction

12 Sunlight, water and oxygen are essential conditions for the germination of seeds. This is because a germinating seed needs air to breathe, water to make the seed coat soft, and warmth for the cell of the seed to become active. Stages of germination ACTIVITY Condition for seed germination To study the condition required for seed germination. Take four plates. Mark them A, B, C, D. Place dry cotton and some dry bean seeds in plate A. Put this plate on a window sill where it can get air and sunlight for warmth. Put moist cotton and some soaked seeds in plate B and keep it on a window sill. Keep the cotton moist all the time. Put some of the soaked bean seeds in a beaker C and cover with water. Keep this plate on a window sill. Put some soaked bean seeds in plate D and place it inside a refrigerator. Watch the bean seeds every day. A B C D Dry seeds on dry cotton Soaked seeds on moist cotton Soaked seeds in water What do you observe? After 2-3 days, you will observe the following: Plate Did the plant grow or not Reason A No There was no water Soaked seeds in the refrigerator B Yes The seed had air, water and sunlight for warmth C No Since seeds were soaked in water, they did not get any air or warmth D No It was very cold in the refrigerator. Plants Reproduction 7

13 DISPERSAL OF SEEDS Plants are fixed to the ground and cannot move from one place to another. Plants generally produce many seeds. If all the seeds were to grow GO FACT near the mother plant, not all would survive. They would The seeds of the sycamore plant have wings which spin not get enough light, food, water and space to grow. To through the air like mini overcome this problem, nature has provided some agents to helicopters. Such seeds get dispersed by wind easily. scatter these seeds. This process of scattering of seeds away from the mother plant is called dispersal. Dispersal of seeds occur in many ways. Excellent agents like wind, water and animals help in the dispersal of seeds. Explosion of dry fruit is another method of seed dispersal. Dispersal by wind: Some seeds are very light and small, and usually get dispersed by wind. Seeds of some plants like cotton, madar, hiptage and drumstick are small, light and have wings or hair. Therefore, these seeds are easily carried to distant places by wind. Cotton seed Madar seed Hiptage seed Dispersal by water: Plants which grow along the banks of river, streams and sea disperse their seed by the flow of water, For example, coconut trees which grow near water, are hollow from inside and are covered with thick fibrous rough hair on the outside. These rough hair help it float on water. When a coconut falls from a tree into the water, it floats and travels with the waves and gets deposited far away and grows into a new plant. The lotus fruit is also dispersed Seeds dispersed by water by water. Dispersal by animals: Humans and animals eat fruits and throw the seeds away,which grow into new plants. Some seeds, which have hooks or spikes, stick the hairy skin of animals or the clothing of human beings and are carried away to different places. 8 Plants Reproduction

14 Birds swallow some seeds which come out unchanged in their deposits. Dispersal by explosion of fruits: Some vegetables like pea and balsam burst open or explode when they are ripe. The seeds pop out and get scattered away from the mother plant. Xanthium seed Tiger nail seed Seeds dispersed by animals Pea pod Seeds dispersed by explosion Crops The plants that are grown in large areas during a particular period are called crops. This practice of growing large quantities of plants for food and other purposes is called agriculture. Crops are mainly of three types food crops (wheat, rice, potato, maize, sugarcane, etc,) oil producing crops (sunflower, mustard, etc.) and fibre crops (cotton, silk and jute). In India, crops like wheat and gram are grown in the winter from November to April. They are called rabi crops. These crops do not depend on the monsoon. Vegetables like cabbage, cauliflower, pea and bean grow well in winters. Crops grown in summers from June to October are called kharif crops. Rice, maize, jowar and bajra are kharif crops. These crops depend largely on monsoon rains.vegetables like pumpkin, brinjal and groundnut grow in summers. Essential requirements to produce a good crop are: 1. Farmers should have knowledge about the soil, climate and season for growing different crops. 2. A high-yielding variety of seeds should be used. 3. Farmers should properly irrigate the soil when required. 4. The right amount of fertilizers should be added to the soil. Two kinds of fertilizers are used for this purpose organic and inorganic fertilizers. Organic fertilizers are obtained from decaying plants, cow dung, etc, while inorganic fertilizers are synthesised. For, example, urea and nitrates. 5. Farmers should use insecticides and pesticides to protect their crops from insects. Plants Reproduction 9

15 However, overuse of pesticides can be harmful to the soil and ultimately to our health. CROP PROTECTION AND STORAGE OF SEEDS For better and healthy crops, we must protect them. We should take the following steps to protect crops: We should protect the crops in the field against grazing animals like goats, cows and buffaloes by proper fencing. We should protect the crops against pests such as locusts, grasshoppers, caterpillars and diseases. Ripened crop should be harvested and stored properly as grains. Farmers should keep them safe from moisture and small animals. So, grains should be stored in air-tight containers. A good crop field Protecting crops KEYWORDS Offspring: the young one of animals or plants Embryo: the baby plant Seed coat: thick covering of a seed that protects the baby plant Cotyledons: the seed leaves that contain food for the baby plant Seedling: a baby plant coming out of a seed Germination: the process by which a seed produces a baby plant Insecticides: chemicals used for destroying harmful insects Pesticides: chemicals used for destroying pests SUMMARY Plants are the most useful gift of nature. Plants reproduce by sexual and asexual modes. New plants grow from different parts of a mother plant. The parts of a flower include sepals, petals, stamens and carpel. Pollination is the transfer of pollen grains from one flower to another flower. 10 Plants Reproduction

16 Humming Bird Science-5 40% OFF Publisher : MBD Group Publishers ISBN : Author : Piyush Ganeshiya Type the URL : Get this ebook