5

Archana Shukla

This is my book

I am .................................................

I am in class ...................................

Hands-on Learning in Science

Pref

ace

Wow Science, the series, attempts to present Science through comprehensive and wide ranging content and related activities that provide a joyful learning experience to our young learners. The series follows the recommendations of the National Curriculum Framework (NCF) 2005.

Learning of Science is based on themes that students can relate to in their everyday experiences, and to the commonly observed phenomena in nature. These themes encompass a core body of concepts across both, the life sciences and physical sciences.

The focus of each theme is given below.

There are many living and non-living things in the world. Man seeks to organise these living and non-living things for better understanding of the world he lives in. There are connections among all living things and integrating factors in the variety of non-living things, that help us to classify them. This theme elaborates the importance of diversity.

Nature is full of repeated patterns of changes. We call these patterns ‘cycles’. For example, the life cycles of living things, the water cycle, etc. We can predict events and processes once we understand these cycles. This understanding also helps us to appreciate the Earth as a self-sustaining system.

Various parts that work together to perform a function(s) makes a system. There are man-made systems as well as natural systems. The digestive and respiratory systems are examples of natural systems, while an electrical systems are man-made systems. Understanding systems means understanding how they work and how their various parts interact with one another to perform a particular function.

SYSTEMSCYCLESDIVERSITY

Inquiry-based Warm-upEncourages active student participation and creates opportunity for interaction and discussion.

In This LessonList of major topics covered in the chapter

Info BitInteresting facts that excite students and broaden their

Interactive approachHelps to engage learners and help them connect

ExploreInquiry-based activities to gain a deeper understanding of the concepts learnt

Building BlockObserving, analysing, interpreting and making models to build the understanding of the concepts learnt

AssessIn-text exercise for assessment.

Science TalkDiscussion pointers related to the respective topics, to be initiated by the teacher

Various systems interact within themselves and with each other. This understanding helps to enhance our knowledge of the environment and the role of humans in it. Organisms interact in three ways: within an organism, among various organisms and between organisms, and the environment. The interaction of humans with the environment has led to the development of Science and Technology. Also, the way humans interact with the environment is influenced by Science and Technology. By understanding the interactions between humans and their environment, students can become aware of the consequences of their actions as they learn to take responsibility for these actions.

Changes and movements in everyday life are made possible due to energy. Humans use various forms of energy for various activities. Not just humans, but all living things need energy to carry out life processes. This theme will allow students to appreciate the importance and uses of energy and the need to conserve it.

Appropriate links are included across the five themes to help learners connect their learning with the experiences about the world around them that they would gradually acquire.

ENERGYINTERACTIONS

WorksheetA useful worksheet at the end of each chapter for additional formative evaluation

Think ScienceHelps learners to understand the topic practically, through logical and critical thinking activities

I WonderHands-on activities involving experiments, making observations collecting data, model making, and project work

Connecting ScienceInterdisciplinary activities based on linkages with other subjects within the curriculum.

I Have LearntConcept maps that summarise and link all the concepts learnt in a chapter

Chapters Content Building block

Think Science Explore

I Wonder: (Investigate, Activity, Project work)

Worksheet Science talk

Unit 1- Diversity

Chapter 1 Animal

• List the ways to classify animals• Compare the features of cold and

warm blooded animals• Understand the active hours of

animals• Distinguish between vertebrates and

invertebrates• Explain the adaptations in animals

Chapter 2 Micro organisms

• • List the importance of fungi and

bacteria• Explain the harmful effects of fungi

and bacteria• Understand the need of food

preservation

Unit 2 : Cycles

Chapter 3 Reproductionin Plants

• Reproduction in plants• Pollination and its types• Fertilisation—fruit and seed

formation• Seeds—types, structure and dispersal• Modes of vegetative reproduction in

plants

Chapter 4 Reproductionin Animals

• Reproduction by laying eggs (e.g.,

• Reproduction through giving birth to young ones (mammals)

• Reproduction and its types: budding, fragmentation and regeneration

Chapter 5 States of Matter

• Interconversion of states of matter and phenomena involved in it.

• Applications of interconversion of states of matter

• Solution and its types• Impurities in water and their removal• Water conservation

Unit 3: Systems

Chapter 6 Human Body Systems

• Respiratory system• Circulatory system• Skeletal system• Nervous system

Understanding the book

Chapters Content Building block

Think Science Explore

I Wonder: (Investigate, Activity, Project work)

Worksheet Science talk

Unit 1- Diversity

Chapter 1 Animal

• List the ways to classify animals• Compare the features of cold and

warm blooded animals• Understand the active hours of

animals• Distinguish between vertebrates and

invertebrates• Explain the adaptations in animals

Chapter 2 Micro organisms

• • List the importance of fungi and

bacteria• Explain the harmful effects of fungi

and bacteria• Understand the need of food

preservation

Unit 2 : Cycles

Chapter 3 Reproductionin Plants

• Reproduction in plants• Pollination and its types• Fertilisation—fruit and seed

formation• Seeds—types, structure and dispersal• Modes of vegetative reproduction in

plants

Chapter 4 Reproductionin Animals

• Reproduction by laying eggs (e.g.,

• Reproduction through giving birth to young ones (mammals)

• Reproduction and its types: budding, fragmentation and regeneration

Chapter 5 States of Matter

• Interconversion of states of matter and phenomena involved in it.

• Applications of interconversion of states of matter

• Solution and its types• Impurities in water and their removal• Water conservation

Unit 3: Systems

Chapter 6 Human Body Systems

• Respiratory system• Circulatory system• Skeletal system• Nervous system

Chapters ContentBuilding block

Think Science

Explore

I Wonder: (Investigate, Activity, Project work)

WorksheetScience talk

Chapter 7 Transport Systemof a Plant

• Transport system of a plant—parts and their functions

• Transportation of water and nutrients throughout the plant body

• Comparison between transport system of plants and that of humans

Unit 4: Interactions

Chapter 8 Measurement

• How are the length, mass, volume, time and temperature of the objects measured

• Units of length, mass, volume, time and temperature

• To solve the basic numerical problems based on unit conversions

Chapter 9 Force

• How does force affect our day-to-day life

• Why are different types of force important

• How are the force harmful to us

Chapter 10 Simple Machine

• Machines and its types• Types of simple machines• Importance of simple machines in

our life• Complex machine

Chapter 11 OurEnvironment

• Components of environment• Layers of atmosphere• Interaction in environment – food

chain and food web• Positive impact of humans on

environment• Pollution– Result of Human’s

activities• Ways to save our environment

Unit 5: Energy

Chapter 12 Forms of Energy

• What are different forms of energy• What type of energy changes can be

observed in our surroundings• What type of energy do fuels have• How are various types of fuels useful

to us

Chapter 13 Energy fromFood

• Why do living organisms need energy

• How do we get energy from food• What are food groups and food

pyramid• Why is food pyramid important• Why should we take a balanced diet

ContentsUNIT I: DIVERSITY

1. Animal Classification 7

2. Microorganisms 20

UNIT II: CYCLES

3. Reproduction in Plants 31

4. Reproduction in Animals 43

5. States of Matter 52

UNIT III: SYSTEMS

6. Human Body Systems 64

7. Transport System of a Plant 78

UNIT IV: INTERACTIONS

8. Measurement 86

9. Force 96

10. Simple Machine 108

11. Our Environment 118

UNIT V: ENERGY

12. Forms of Energy 133

13. Energy from Food 146

7

On the Basis of Body TemperatureAnimals can be categorised into two groups based on their body temperature.

There are so many animals here! They are

drinking water and enjoying the sunlight, unlike these

hippopotamuses.

�ere is a great variety of animals on the Earth. �ey di�er not only in their body coverings, but also in their body temperature, hours of activity, and internal body structures. So animals can be categorised into di�erent groups on the basis of these characteristics.

It is because animals have different body temperature. Hippopotamuses remain cool by staying in water or mud.

• List the ways to classify animals

• Compare the features of cold and warm blooded animals

•

•

•

Unit 1: Diversity

Animal Classification

In This Lesson

1

Cold-blooded animals or ectotherms

Look at those hippopotamuses! Why are they not getting out of the

river?

8

Cold-blooded AnimalsAnimals that need external energy to control their body temperature are cold-blooded or ectotherms. �ey take energy from their surroundings. Lizards, chameleon, snakes (reptiles) and frogs and salamanders (amphibians) are some cold-blooded animals.�ese animals do not have �xed body temperature. �eir body temperature corresponds to that of their surrounding. �eir body temperature decreases during winter, when it is cold, and increases during summers when the atmospheric temperature increases.

Warm-blooded AnimalsWarm-blooded animals can control their body temperature internally and are known as endotherms. �ese animals have a �xed body temperature that does not change with the change in the atmospheric temperature.Humans, lions, bears, deer and birds are some warm–blooded animals.

On the Basis of Hours of ActivityMany animals are active during the day, while some are active during the night. Based on their hours of activity, animals can be classi�ed into 3 groups— diurnal, nocturnal and crepuscular.

Hours of Activity

Diurnal(active during the day time)

Noctural(active at night)

Crepuscular(active at dawn and dusk)

Warm-blooded animals or endotherms

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Diurnal Animals

Nocturnal Animals

Crepuscular Animals

Deer

Bear

MothBat

HorseAmerican RobinSheepDolphin

Owl

�e animals which are active during the day time and inactive during the night time are called diurnal animals. Most mammals and birds are diurnal.

Some animals are active during the night and sleep during the day time. �ese animals are called nocturnal animals. �ey have enhanced night vision that helps them to see properly in night. For example—owls, bats, and some frogs.

Some animals become most active at sunrise (dawn) and at the sunset (dusk); they are known as crepuscular. For example—skunks, �re�ies, and deer. Pets like dogs, cats, rabbits and hamsters, are generally considered as crepuscular.

Horse and humans have one more common

characteristic that is the backbone.

Look at that horse! Its body is covered with hair, just like

our body.

On the Basis of Presence or Absence of a BackboneAnimals are grouped into two broad categories—vertebrates and invertebrates.

It is also a diurnal animal as humans are.

Bats are mammals

Info Bit

Vertebrates

Animals with backbones or spinal cord are called vertebrates. �ey have an internal skeletal system made of bones and muscles. Vertebrates have advanced nervous system. Example—humans, monkeys and birds. Vertebrate animals are categorised into 5 groups namely, �sh, amphibians, reptiles, birds and mammals. �ey di�er in their characteristics.

Scales

Gills

Fins

Amphibians‘Amphi’ means both. Amphibians are those animals which can live on land as well as in water. �ey breathe through lungs as well as through moist skin, but their larvae breathe through gills as they live in water. �ey lay eggs to reproduce. �ey are cold-blooded.Frogs, salamanders and urodeles are all amphibians.

Urodeles

Salamander

Fish, frogs, and birds are vertebrates as they have backbones. But

other features of their bodies are different.

Fish are also vertebrates.

Both birds and humans are

vertebrates, but

while humans can’t.

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FishFish live in water. �ey have gills to breathe in water.�ey have streamlined bodies covered with scales and have �ns to swim. Most �sh lay eggs to reproduce. �ey are cold-blooded.

Info Bit

Vertebrates Invertebrates Animals

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ReptilesReptiles generally live on land but some of them swim well and may breed in water. �ey breathe through lungs and their body is covered with hard scales.For example, crocodiles, snakes, lizards, etc.

�ey are also cold-blooded. Reptiles lay so�-shelled eggs.

BirdsBirds are the only animals with feathers. �eir feathers keep them warm and help them to �y. All birds have a beak, two wings, and two legs. �e forelimbs of birds are modi�ed into wings.

�ey breathe through lungs and are warm-blooded.�ey generally live on trees and have a very light skeletal system that is highly adapted for �ight. Birds have hollow light bones but some birds, such as emu and ostrich, which do not �y have heavy bones.

Beak

Info Bit

Birds reproduce by laying eggs which are protected by hard shells.

MammalsMammals are the only animals with hair or fur on their bodies. �ey are warm-blooded and breathe through lungs.

Most female mammals give birth to their young ones and produce milk to feed their young ones.Example – humans, monkeys, rabbits, blue whales and bats are all mammals.

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InvertebratesAnimals which do not have backbones or spinal cords are called invertebrates. �ey lack a skeletal systems but have highly developed nervous system.Insects, worms, star�sh and octopus are common examples of invertebrates.

InsectsAll insects do not look similar.

Honeybee has

Insects have six legs and antennae. �e body of insects is covered by a hard outer covering to protect them. �e body is divided into three parts—head, thorax and abdomen.

Head Thorax Abdomen

�ere are many types of insects, some of them are useful too.

These insects are dangerous.

They bite us and spread diseases.

Chinmaya, you are right, but all insects

do not bite or spread diseases.

Ants�ey are social insects as they live in groups. �ey eat almost anything but black ants eat only fruits and grass.

Mosquitoes�ey bite people, suck their blood and spread diseases. Some mosquitoes breed in stagnant water. Female Anopheles mosquitoes spread malaria.

Science Talk

Honeybees�ey are also social insects as they live in colonies. �ey make hives (beehives). �ey collect nectar from �owers in hives and make honey. �ere is only one queen bee which lays eggs. �e rest of the bees are worker bees.

House�ies�ey spread diseases like cholera, as they carry germs on their hair. �ey feed on the food of humans and other animals and waste materials.

Make a list of 5 insects and

Bees sting us only when they feel they are in danger. They have

an antenna to sense the danger in their

surroundings.

Honeybees give us honey. I love to eat honey but they are dangerous as they can sting us.

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Science Talk

Adaptation in AnimalsAnimals develop special characteristics that help them to survive changes in the environment. Any change in the structure or function of an animal, or any of the parts of its body, by which it becomes more capable to survive, is called adaptation.

Change in body structure Change in behaviour as per need

from one place to another

Structural

Structural AdaptationAnimals adapt with the development of a special part or an organ of their body, to survive with changes in environment. Some common examples are—1. �e powerful legs and streamlined body of cheetahs help

them to run fast and their wide nasal passage and �at ribcage help them to breathe easily while running.

A prehensile tail is the tail of an animal that helps to hold

and manipulate

Behavioural AdaptationSome animals change their behaviour to adapt to the extreme changes in the environment.

HibernationHibernation is a survival strategy through which some animal species conserve energy during extreme weather conditions. Some animals, mainly endotherms or warm-blooded animals such as polar bears, become inactive during winters. �ey sleep with an inactive brain. Some ectotherms, such as reptiles, also hibernate.�e state of inactivity, characterised by low body temperature and slow breathing rate is called hibernation. Animals such as snakes, bear and rats hibernate during winter.

Animals hibernate during winter to save themselves–1. from extreme cold weather. 2. from scarcity of food.

2. �e long trunks of elephants help them to drink large amounts of water, to eat food or to pick objects of their use.

3. �e abdominal pouches of kangaroos help them to carry their babies as they are not properly developed at birth.

4. �e widely spread eyes of rabbits give them a wide range of vision for detecting of danger.

5. �e prehensile tails of monkeys help them to live on trees.

6. �e hooked beaks of birds help them to feed.

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MigrationSome animals and birds travel thousands of miles, from one place to the other, in groups to avoid extreme hot or cold weather. �is seasonal movement of birds and animals is called migration.

Animals and birds migrate—1. to �nd better weather2. to �nd better food 3. to �nd safe place to give birth to young ones.4. for breeding (some birds and animals)

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Info Bit

Presence or Absence of a Backbone

Ectotherms(cold-blooded)

DiurnalVertebrates

Crepusular

and dusk) backbone)

NocturnalBody temperature is controlled

body temperature

Endotherms(warm-blooded)

on the basis of

Science Words

I Have Learnt

16

Tick (

Evaluate

Evaluate

17

Tick (

Evaluate

D. HOTS

1818

WONDERIInvestigate

not smeared with

The layer of acts similar to the or which

to escape from the body and thus keeps the body

Project Work

1919

S E A L J E L L Y F S H

M A D H H K L E S A J K L E

A R L A N S A A F T C

N T T A N S E D R G G B F K

D H O S M G U N O R J A T T

G W O C O A M M G G O A T H O

H O R L S S N F O F V B C S M

R E E Q O D L S T A

L C H M A N Z E E R G G T

A A M O R K D J R E D H Y O

M N U N T D H D K A R S J X

B G C H O N E Y B E E E K L O

R O U T A O A S G J L K E O

G A C H M A N Z E E D T J

W A R M Y Y G J L E M O A N T

1. The camel is called ‘the ship of the desert’. It has several adaptations to survive in the desert.

2. Encircle the names of the animals given in the grid and write them in the suitable column.

Hump

Eyelid

Skin on knee

Hoof

Vertebrates

Mouldy bread under a microscope

These spots are moulds.

Very small living organisms that can only be seen using a microscope are called microorganisms or microbes.

Look at these bread slices. Mould is also a collection of microorganisms.

There are many living organisms in our surrounding that can’t be seen through the naked eye. They may cause diseases.

•

• The importance of fungi and bacteria

•

•

Microorganisms

In This Lesson

2These spots carry very small organisms that grow on the fruits

and cause rot.Chinmaya, look at these fruits! There are some spots on

them.

I think these spots appear when fruits

rot.

The first microscope was invented by Hans Janssen and his son Zacharias Janssen.

Info Bit

20

21

Types of microorganismsMicroorganisms are categorised into five groups.

Fungi Bacteria ProtozoaAlgae Virus

Microbes

FungiFungi are found in various sizes. Some, such as mushrooms and yeast, are large enough to be seen with the naked eye, while others, such as moulds, are so small that microscopes have to be used to see them.

Mushrooms Yeast cells under a microscope

Fungi growing on the trunk of a tree

Moulds grow on the surface of a liquid (oil) and

thus feed upon it.

Harmful Effects of FungiMost fungi have harmful effects. Fungi are responsible for diseases like ringworm and athlete’s foot.

Fungus - A harmful organism

•

• The importance of fungi and bacteria

•

•

causes diseases in humans and other animals

can be poisonous

spoils food, fruits and vegetables

causes plant diseases

Importance of FungiThough most fungi spoil our food materials and cause diseases, some of them are useful too.

Bacteria

Mushrooms and Yeast

Used as food

Penicillin, an antibiotic, is produced from a fungus Penicillium.

Produce medicinesHelp to recycle nutrients in soil

Soy sauce VinegarBread

Food made using fungi Used in bakery shops

Saprophytic bacteria and fungi recycle nutrients, by feeding on dead and decayed materials.

Soil

To bake cake, pizza, biscuits, etc.

Look at these tomatoes! They also have spots

on them.

I think, it must be due to the

fungi that grow on them.

No, these are because of the bacteria

growing on them.

22

Think Science

One day, Jigyasa’s Science teacher took the students of her class outside, to the school park. Jigyasa found that some leaves of a plant were looking different from the others. Some of the leaves had brownish yellow spots. She was puzzled to see such leaves. Can you help her to find the reason behind it? Write your view for the same.

In air

In food

Bacteria on the surface of the tongue.

Good BacteriaGood bacteria are useful to us in many ways.

Bacteria in the roots of leguminous plants help to

absorb nitrogen from the soil.

Bacteria also help to turn milk into cheese, butter and yogurt.

Bacteria are living organisms and can only be seen under a microscope. Bacteria are everywhere. Some bacteria are good, and some are bad.

Milk Curd

Bacteria (lactobacillus) convert milk into curd.

Bad BacteriaBacteria cause many diseases in humans, plants, and animals.

Do you know bacteria grow on our teeth and cause teeth

decay?

No Jigyas. They actually grow on food particles that get stuck between

our teeth.

Bacteria are also the cause of some

other diseases.

Bacteria grow only in presence of air and moisture.

Info Bit

23

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If growth of bacteria, fungi and other microbes on food items is prevented, the spoiling of food can be stopped. Thus, food can be preserved.

Food PreservationFungi and bacteria

spoil our food. Can we not stop them from

doing it?

Vaigyanik Chacha, how can we

preserve our food?

Spoiling of food can be prevented by preserving our

food items.

Algae grown in pond water. They are green in colour. Some algae can be blue or red in colour.

Early blight in tomato

Wilt in oakCitrus canker on lime

Bacterial diseases in animals Bacterial diseases in plants

Cholera Diarrhoeal diseases Pneumonia

Tuberculosis Anthrax, Typhoid Tetanus

Diphtheria Whooping cough Leprosy

Think Science

On a summer day, Chirag’s mother forgot to keep the milk in refrigerator. Milk was left in the warm kitchen overnight. In the morning, she noticed that the milk had curdled. Now you want to find out—

1. the reason for the curdling of milk; 2. how milk looks after curdling.

Other MicrobesNot only fungi and bacteria, but other microbes, such as algae, protozoa, and viruses, also cause diseases in plants and animals.

Polio, chicken pox, dengue fever, measles, and mumps are some diseases caused by viruses, while malaria and sleeping sickness are protozoan diseases.

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Some common methods of food preservation are:

Pasteurisation: It destroys disease causing bacteria and other microbes by boiling and then cooling.

Canning and Bottling: This means storing jams, sauces, and similar items, in air tight cans and bottles.

Refrigerating: This means keeping food at low temperature for short–term preservation.

Pickling: It means mixing salt and oil to fruit and vegetables.

Deep Freezing: This involves keeping food items in freezer for long-time preservation.

Drying: This is the oldest way of food preservation.

Science Words

Types of Microbes

Fungi

useful usefulharmful harmful

Algae Protozoa Virus Bacteria

Microbes or microorganisms are small living organisms that can be seen only by using a microscope.

as food spoil our food

producing medicines

cause plant and animal disease

in bakery shops

are poisonous

convert milk into curd

live in the intestine and help in digestion

help leguminous plants to absorb nitrogen

causes many diseases in humans, plants and animals

I Have Learnt

26

Tick ( ) the correct answers.

1. The microscope is generally used to observe–

a. plants b. animals c. microbes d. mushrooms

2. Which of the following lives in human intestine and help in digestion?

a. moulds b. mushrooms c. yeast d. bacteria

3. Which statement about microbes is incorrect?

a. Some microbes are useful to us, they do not harm us.

b. Most of them can be seen clearly only under a microscope.

c. Some of them are useful but some are harmful also.

d. All of these.

4. The microbes generally used for baking food items like pizza and biscuits are–

a. moulds b. mushrooms c. yeast d. bacteria

5. A microbe that can be seen with the naked eye is–

a. virus b. mushroom c. bacteria d. none of these

2. We make pickles and sauces of vegetables. What is the scientific reason behind it? 3. Name any two diseases caused by protozoa. 4. Name any two bacterial diseases each in plants and animals.

5. A 7-year old boy eats many chocolates and candies, everyday. Soon he complains of toothache. What could be the reason of toothache? How can it be prevented?

26

Evaluate

27

1. a. Your parents and teachers ask you to wash your hands and other exposed parts of your body, whenever you come back from a playground. What is the reason for it?

What could happen if you do not wash the parts of your body properly?

b. Why are some bacteria called good bacteria? Mention two reasons.

2. Deepu bought a packet of milk and drank it. It tasted sour. A few hours later, he became ill. Why did Deepu become ill? How can we prevent fresh milk from getting sour? Explain.

3. ‘Fungi are harmful as well as useful to us’. Justify the statement. Mention any three points.

D. HOTS Identify the given organ systems. How do bacteria affect both the systems?

E. Values and life skills A child in your play group eats junk food regularly. You have noticed that he often puts his finger

in his mouth to remove stuck particles. What dangers do his habits pose? What advise would you give him?

27

Presence of bacteria

28

WONDERI

28

I will:

I need:

• 1 bottle

• Yeast powder

• Sugar

• Balloon

• Warm water

1. Fill half the bottle with warm water.

2. Add half spoon sugar and yeast powder into it.

3. Attach a balloon at the mouth of the bottle and fix it using a rubber band and keep it for 3-4 hours, undisturbed.

The balloon ........................... after sometime, as it is filled with ........................... gas.

Yeasts are ........................... organisms.

Task: Observe the growth of moulds on bread slices or fruits.

A slice of bread or an orange (a fruit), an air tight container or zip pouch and water.

Steps:

1. Take a slice of bread or fruit and sprinkle small amount of water on it.

2. Keep it in the zip pouch or the container and seal it properly.

3. Now keep the closed container in a warm place for 4-5 days.

There are ........................... on the food item.

Yellow green spots are seen due to ...........................

Project Work

Make a PowerPoint presentation of 5-8 slides to introduce the 5 types of microorganisms (fungi, bacteria, algae, virus and protozoa) and the diseases caused by them.

2929

1. Answer the following questions.

a. Your classmate looks at his palm under a microscope and observes what is shown in the picture. Will you shake hands with him? Why? What will you tell him?

.....................................................................................................

.....................................................................................................

.....................................................................................................

.....................................................................................................

b. Microbes are good as well as bad for us, in many ways. Bacteria convert milk into curd; it means there are bacteria in curd. Should we eat curd? Why?

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

2. Study the object shown below.

a. What is the instrument shown above?

.............................................................................................................................................

b. What is the function of this instrument?

.............................................................................................................................................

c. Circle the organisms that can only be viewed using the above instrument.

paramecium mosquito fern bacteria

woodlouse

mould on bread germs on hands algae in soil

pitcher plant bacterial disease in a tomato

30

Connecting ScienceScientists have discovered fungi that will help you battle bacterial diseases. Many times when you get sick, doctor says that you have a bacterial infection. He prescribes an antibiotic to help you get better. Antibiotics are drugs which inhibit the growth of bacteria and destroy it. There are many types of antibiotics known to us. The first antibiotic, penicillin, was developed from a fungus named as Penicillium (found on an orange).

It was discovered by Alexander Fleming, Professor of Bacteriology at St. Mary’s Hospital in London on February 14,1929.

Science 1. What are moulds?

2. How are antibiotics helpful for us?

Social Science

1. In which continent is London situated?

2. Use internet and find out the history of the discovery of first antibiotic.

Math

Search and find out the area of London and compare it with your city.

English

1. Write the word meaning of–Inhibit, Prescribe, Battle and Bacteriology.

2. The word antibiotic is made up of two words. ‘anti’ is a prefix that means “against” or “oppiste of”. Find out and write five words with the prefix ‘anti’.

IT

Make a PowerPoint presentation of 5-7 slides on ‘Antibiotics’.

Penicillium mould grown on an orange.

31

They collect their food from the flowers. They also help the flowers

to reproduce.I wonder, why do butterflies sit on colourful flowers?

Honeybees also sit on flowers.

Why?

How Plants GrowWe see plants grow all around us. From food to clothes, we obtain many things of our daily use from plants. If you plan to make a vegetable garden, how would you do that?

Have you noticed the seeds inside the fruits and vegetables you eat? You can grow new plants from these seeds.

• How plants grow•

Unit 2: Cycles

Reproduction in Plants

In This Lesson

3

When butterflies, honeybees and other insects sit on flowers, pollen stick to their legs. The pollen grains are then transferred to other flowers. These pollens help plants to reproduce.

Pollens (containing

32

Embryo: It develops

Micropyle: It is a hole through which

Endosperm: It is a

Seed coat: It protects Young plant

I am trying to open a wheat seed, as I did with the bean

seed, but I am unable to do it. Why is it so?

Wheat seeds have only one cotyledon, while bean seeds have two cotyledons. This is the reason; we are unable to open wheat seeds.

Seeds which contain only one cotyledon are called monocotyledons (monocots) and the seeds which contain two cotyledons are called dicotyledons (dicots). Monocot seeds

(Mono-means one)Dicot seeds

(Di-means two)

Rice, wheat, maize, and rye are monocot seeds, whereas gram seeds, rajma seeds, and pea seeds are dicot seeds.

Structure of a SeedA seed has a young baby plant inside it, called the embryo. The embryo is protected by a hard and waterproof seed coat.

Types of Seeds

All seeds need water, oxygen and appropriate temperature (warmth) to germinate. Some seeds also need sunlight. When the temperature is low, seeds take a longer time to germinate.

Plumule emerges as a

Plumule develops into

Radicle develops into roots

down and radicle emerges as a

Building Block

Ass

ess

water

oil

GerminationSeeds produce new plants under suitable conditions of air, water and sunlight. The process of growth of a seed into a new plant is known as germination.

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Wow! there is a plant growing from the wall.

Where did it come from?

That’s surprising! There is no other plant, here. How did it grow here?

It is the result of seed dispersal by

animals.

Seed Dispersal

The seeds of some plants are transported from one place to other by birds, animals, humans, etc. The process is called seed dispersal.The seeds of plants need to disperse to:1. ensure the continuity and survival of the species.2. avoid overcrowding in one place.3. prevent the competition of parent plants with offspring, for water, nutrients, and sunlight.Sometimes the seeds are not dispersed far from the parent plant. This affects the growth of the plant.

in the dispersal of seeds;

Info Bit

Seeds dispersed by wind are very light.

Dandelion

By wind By birds and animals

Coconut Jewel weedLotus Violet

By water By bursting

Bean

By humans Think Science

wind while coconut

Flowers

Plants reproduce through

Methods of ReproductionA plant undergoes different processes to reproduce. Plants reproduce in two ways.

Many plants reproduce through flowers.

PollinationPollination is the transfer of pollen grains from the anther to the stigma of a flower. The pollen grains may come from the same flower or from other flower. Insects, birds, animals, water, and wind help to pollinate flowers.

Structure of a FlowerFlowers are the reproductive organs of a plant.

Petals

Sepalscalled corolla

structures that protect

calyx

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Cross-pollination occurs in plants that have only one reproductive organ, either stamen or pistil. Apples, grapes, tulips, pumpkins, grasses, plums, and other plants, reproduce by cross-pollination.

Cross-pollinationPollen grains

Self-pollinationSelf-pollination occurs in plants that have both reproductive parts. Wheat, tobacco, pea plants, and others reproduce by self-pollination.

Occurence of Reproductive Organs

Some flowers have both male and female reproductive organs while others have only one. The flowers of papaya, cucumber, and pumpkin have either stamens or pistil, whereas the flowers of hibiscus, mustard, and lily have both pistil and stamens.

Stamen is the male reproductive part of a flower. It is made of filament and anther. Anther contains pollen and pollen contains pollen grains.

Pollen grains are microscopic bodies that contain the male reproductive cells of a plant.

Pistil is the female reproductive part of a flower. It consists of stigma, style, and ovary. Ovary contains ovules.

Pedicel

Sepal

Filament

Petal

Stamen

Pollen

Anther

Stigma

Pistil

flower flower flower

Types of Pollination

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pollen from the

to another plant of

attaches to the pistil of a

Pollen

Insects: Flowering plants are pollinated by insects. For example: jasmine, onion, strawberry and

mustard

By Water: Aquatic plants are pollinated through water. For example, vallisnaria, hydrilla

and lotus

Birds and Animals: For example, mango,

banana and guava

By Wind: Plants that do not have attractive �owers. �ey

are pollinated by the wind. For example, coconut palm, date

palm and maize

Di�erent ways of pollen transfer through cross-pollination

Info Bit

FertilisationThese seeds produce new

plants.What happens

after pollination?

After pollination, the ovary of flowers develop into fruits

and fruits bear seeds.

After pollination, the pollen grains reach the stigma, and then, the ovary of the flower. The ovary contains ovules. Pollen grains fuse with the ovules. Fusion of pollen grains with ovules is called fertilisation.

After fertilisation, the ovary of the flower enlarges and becomes a fruit, and each fertilised ovule develops into a single seed.

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Some plants can reproduce from their own parts, like roots, stem and leaves. This is called vegetative reproduction.

Vegetative Reproduction

By leaves: In some plants, adventitious buds develop on leaves. When a leaf comes in contact with soil, these buds develop into new plants. Bryophyllum and Begonia are two plants that use this method.

By Roots: �e roots of some plants develop adventitious buds on them. �ese buds grow into new plants. Dahlia and sweet potato reproduce by this method.

By Stem: Garlic, potato, ginger and turmeric, have special types of stems that have buds which grow into new plants. Rose plants can also be grown from their stems.

I want to plant a rose bush in my

garden, but I do not have its seeds.

Chinmaya, to plant a rose you do not

need seeds. You can grow another rose plant from its stem

itself.

The ovary protects the seeds until they are ready to be released. When this happens, we say the fruit is ripe.

Some plants produce large

Info Bit

Ways of vegetative reproduction

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Tick ( ) the correct answers.

Evaluate

I Have Learnt

Seed dispersal happens through

wind water humans

Science Words

occurs in plants having

•

•

Seed dispersal happens through

Structure of a seed

40

41

Pollen

D. HOTS

E. Values and life skills

42

WONDERI

42

I will:

I need:

Project Work

4343

1. Complete the following mind map with suitable words.

2. Label the picture.

3. Observe the following flowchart and name the processes ‘A’ and ‘B’ as well as the plant parts ‘X’ and ‘Y’.

By ____________

Flowering plants are

By __________ By ____________

Plants that do not have

By Water

Different ways to transfer pollen in cross-

pollination

pollen from the anther

the ovule

stigma of a flower and pollen goes down to the

transferred to

then

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Some animals give birth to young ones while some animals

lay eggs.

Look! The pigeons have laid eggs in the nest.

Soon, baby pigeons will hatch from these eggs.

From some parts of their own body.laying eggs or giving birth to young ones.

by involvement of both parents through single parent

Animals reproduce in two ways

My cat also gave birth to two kittens.

But they did not hatch from the eggs,

like pigeons!

Teacher’s note

Here ‘animals’ means animal kingdom.

•

•

•

Reproduction in Animals

In This Lesson

4

Most animals reproduce either by laying eggs or by giving birth to young ones. But there are some animals which produce new individuals from parts of their own body.

Reproduction by Laying EggsFish, amphibians, reptiles, and birds are egg-laying animals while mammals give birth to young ones. Reproduction involving both the parents allows for greater variation within species.

Can the eggs which we store in the refrigerator also

hatch, if we do not disturb them?

Egg-laying animals

Reptiles and Birds

Male cells are delivered into the body of the female where they fuse to produce eggs. Eggs hatch into new offspring.

Amphibians and FishFemales produce eggs outside their body and then males fertilise the eggs. �e fertilised eggs hatch into new o�spring.

Birds and reptiles sit on their eggs to give them warmth for a fixed time duration. It is called the incubation period. The incubation period of chicken eggs is 21 days while that for ostrich it is 42 days. The egg hatches into a new baby after completion of the incubation period.

Generally, fish and amphibians do not incubate their eggs.

Hatching of Eggs No, Chinmaya, an egg hatches only when it gets the right amount of

warmth.

A hen incubating its eggs.

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Platypus and echidna lay eggs though they are mammals.

Info Bit

Artificial electric incubators are used to hatch eggs for commercial purposes. These devices provide the required temperature and humidity for the eggs to hatch into new babies. The incubation temperature for chicken eggs is approximately 37.5 degree Celsius.

Science Talk

Mammals Give Birth to Young OnesMost mammals, such as rat, cat, dog, whale and humans, give birth to young ones. The baby develops inside the mother’s womb.

The male reproductive cell fuses with that of a female and fertilisation takes place. Fertilised egg, called an embryo, develops inside the mother’s womb.

The time period in which fertilised eggs develop into a baby, ending at birth is called gestation period.

The gestation period in humans is 9 months or 266 days.

1 monthembryo

foetus

2 month3 month

4 month

5 month

6 month

7 month8 month

9 month

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Think Science

Ria’s mother bought 10 eggs this weekend. Ria took 2 eggs out of them. She kept one egg in the freezer and the other in her almirah in a warm place. What will she observe in both cases? Make a table and write your observations.

Info Bit

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If a baby develops inside the mother’s womb, then

how do some animals produce new offspring using external parts of

their body?

These animals do not need male and female reproductive cells to

reproduce. They reproduce as a single parent.

Find out names of some other animals who reproduce as single parents. How do they produce their off spring?

Ass

ess

1. Hens sit on their eggs to hatch them. How many days do they need to sit on those eggs?

not incubate their eggs.

3. What is the incubation period for an ostrich egg?

4. What is a fertilised egg called?

5. What is the gestation period in humans?

Some animals reproduce through certain external parts of their body. This reproduction requires only one parent to produce a new offspring.

Reproduction Through Single Parent

BuddingA new o�spring develops from an outgrowth or a bud of the body of the parent. For example, in hydra.

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RegenerationA piece of the body of the parent gets detached. It later grows and develops into a new individual. For example, in star�sh.

Fragmentation�e body of the parent breaks down into fragments and each piece can grow into a new o�spring. For example, in planaria.

Bud

Tentacles

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Tick ( ) the correct answers.

1. The animal/animals which reproduce by laying eggs is/are–a. birds b. snakes c. echidna d. all of these

2. Fusion of male cells with female eggs produces–a. embryo b. offspring c. adult baby d. none of these

a. budding b. fragmentation c. both a. and b. d. none of these

4. The gestation period in elephants is of–a. 290 days b. 480 days c. 617 days d. 70 days

Reproduction in Animals

through

single parent

from the parts of their body

both parents

by

laying eggs

Hydra Planaria Starfish

BirdsReptilesAmphibiansFish

Mammals

giving birth to young onesBudding RegenerationFragmentation

Evaluate

Science Words

I Have Learnt

49

5. The device used for artificial incubation is–a. incubator b. desiccator c. oven d. microwave

2. Define fertilisation. What are fertilised eggs called?

3. Mammals reproduce by giving birth to young ones. Their babies develop inside the womb of the

4. A boy was surprised to see few white sticky and slippery dots at the bottom of his fish aquarium. What can it be? Why did it happen?

5. Frogs fertilise their eggs outside their body. In the

the female frog. Give a reason for carrying.

a. Why do birds sit on their eggs?b. Why are both the male and the female parents required for reproduction in some animals?

D. HOTS Complete the given mind map with suitable words.

Male frog sitting on the eggs.

Single parent reproduction in animals

only ________ parent

budding

____________

____________

____________

involves

may occur by

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WONDERI

50

I will:

I need:

1. Form a questionnaire before visiting the poultry farm. You can use the given pointers—

a. eating habits of a chicken

b. how incubators work

c. duration of incubation period

d. precautions taken while incubating eggs

and take a tour of the farm.

3. Observe each section of the farm carefully.

4. Fill your questionnaire on the basis of the information collected.

5. Take help of the teacher/incharge to find answers for questions you could not answer.

1. The production of eggs in a poultry farm.

2. How incubators work.

Make a paper presentation/PowerPoint presentation/an exhibit on ‘Reproduction in animals’.

Project Work

Observe the permanent slide of ‘budding in hydra’.

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1. Complete the given Venn diagram.

2. Solve the crossword puzzle.

1.

2.

3. 4.

5. 6.

Across:1. Method through which starfish

reproduces.3. Mode of reproduction by which

parental body breaks down into fragments.

5. Method through which Hydra reproduces.

Down:2. Method to produce new individuals.4. It is a fertilised egg.6. The process in which animals sit on

their eggs to give them warmth.

budding fragmentationcommon in both

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