Diversity In The Living World

Good morning, my dear students! I am so happy to see all of you today. Today, we are going to learn about something truly wonderful and all around us — the amazing diversity in the living world. This is Chapter 2 of your Science textbook, and I promise you, by the end of this lesson, you will start looking at the plants and animals around you in a completely new way.

So students, let's begin!

Imagine it is a pleasant morning after yesterday's refreshing rain. Your science teacher, Madam Sulekha, has arranged something very special for you. She has invited two guests to the school — Dr Raghu, who is a scientist at a nearby Research Laboratory, and Maniram chacha, an elderly person from a nearby community. Now, Maniram chacha is very special — he is an expert at mimicking bird calls, and he is brilliant at identifying all kinds of plants and animals. Wouldn't it be wonderful to go on a nature walk with such knowledgeable people? That is exactly what you are going to do!

Dr Raghu tells all the students that the objective of this nature walk is to experience the beauty and variety of plants and animals in nature. The students are so excited! They carry their notebooks, pens, and water bottles, and off they go!

As they walk, they start exploring the plants and animals around them. Dr Raghu advises them to notice the variety of smells in the park and emphasizes that they must respect all living creatures and observe them without disturbing them. Maniram chacha tells the students to not only observe different plants and animals but also to carefully listen to different sounds. The students come across a variety of plants — grasses, bushes, and large trees. They also observe a variety of birds sitting on the branches of trees, butterflies moving from flower to flower, and monkeys jumping from one tree to another. They record their observations in their notebooks and discuss them with Dr Raghu and Maniram chacha.

The students can hear the chirping of birds. Dr Raghu informs them that each bird has a unique chirp. This is an example of diversity in nature. Just think about it — no two birds sound exactly the same! Dr Raghu requests Maniram chacha to mimic calls of some birds, and he does so beautifully. The students enthusiastically start copying him.

Now, I want you to think about this — have you ever observed different plants and animals around you? Perhaps in your garden, on your way to school, or in a park? I want you to share and discuss your observations with your friends and your teacher. That is exactly what Activity 2.1 asks you to do.

So students, let us understand what Activity 2.1 is all about. It says — plan a nature walk with your teacher to a park or a nearby forest. While on the nature walk, observe different plants, insects, birds, and other animals. Also, note the weather conditions — whether it is hot, cold, windy, and so on. You can collect different types of fallen leaves or flowers and create a scrapbook. But very importantly, take care of the plants and animals in nature. Ensure that you do not disturb the plants and animals in the park. Do not pluck leaves and flowers! This is very important, my dear students — we must always respect nature.

Now, record your observations in Table 2.1 about the features of stems, leaves, flowers, and anything interesting in various plants. The table gives you some examples. For instance, for common grass, the stem is soft and thin. A single leaf grows alternatively from different points on the stem. For Tulsi, also known as Holy Basil, the stem is hard and thin. The leaves are arranged in a pair of leaves in opposite directions, and the flowers are pinkish purple. For Hibiscus, also called Gudhal, the stem is hard. You need to fill in the other details. For Neem, which is a very common tree in India, the stem is hard and thick, and the leaves have a smooth surface. And then you can add any other plant that you observe.

Now, after doing this activity, think about this question — what similarities and differences did you find among the plants that you observed?

You must have observed that plants have a variety of features such as — they can be tall or short, they can have hard or soft stems, they have different shapes of leaves and their arrangement on the stem or branches can be different, and flowers vary in colour, shape, and scent. Isn't that wonderful?

Now, let us also create a list of animals you observed during this walk or from your previous experiences. Record the places where they live, the food they eat, and the way they move around in Table 2.2. Some examples are provided. For a crow, it lives in trees, eats insects, and moves by flying and walking. You might have seen a crow carrying a twig in its beak — that is interesting! For an ant, it lives in a nest in the soil and burrow, eats leaves, seeds, and insects, and moves by crawling. Ants have six legs. For a cow, it lives in a shed or barn, eats grasses and leaves, and moves by walking. You can add more animals to this table.

Now, what are the similarities and differences among the animals that you have observed and recorded?

You would have observed that some animals live on land while some others live on trees. Birds live on trees. Fish live in water, and some animals like frogs live on land as well as in water. Animals consume a diverse range of foods and exhibit a variety of movements. Some crawl, some fly, some walk, some swim — isn't that amazing?

Now, the chapter also asks you to sketch the plants and animals observed by you in your notebook or prepare a scrapbook with leaves, flowers from different plants and feathers from animals. Write all the details you have gathered about them. And while travelling to and from school, observe your surroundings and look out for a variety of plants and animals. Add the name of any plant or animal that you have not listed before in Tables 2.1 and 2.2.

Now, let us do Activity 2.2. Close your eyes for 30 seconds and think of one plant and one animal that you have closely observed and appreciated very much. Now each one of you can draw the plant and animal that you thought of on the blackboard. What are your observations about the various plants and animals that have been drawn? How many different plants and animals did the entire class draw on the blackboard? Do you think that there may be many more varieties of plants and animals other than those drawn on the board?

This is a very important point, students. The variety of plants and animals found in a particular region contributes to the biodiversity of that region. Biodiversity simply means the variety of living organisms in a particular area. And each member in the biodiversity of a region has a different role to play. For example, trees provide food and shelter to some birds and other animals. Animals help in spreading seeds after eating fruits. Can you think of more such examples? This shows that plants and animals are dependent on each other. This is what we call interdependence in nature.

Now, students, let us move on to Section 2.2 — How to Group Plants and Animals?

Think about this — how would you arrange your books and notebooks in groups? Would arranging them in groups help you better organise your school bag? Obviously, yes! When we group similar things together, it becomes easier to find them and understand them better.

Now, let us look at the world around us. We are surrounded by a variety of plants and animals with different features about which you have learnt in section 2.1. We can group them based on similarities and differences among them.

Let us do Activity 2.3. Collect pictures of various other plants and animals. Cut their pictures from old magazines, newspapers, charts and other sources. Paste each of these pictures on a different card. Divide your class in groups of 5-6 students each. Pool the cards prepared by the students in your group. Observe various features of plants and animals shown on the cards. Recall the features of plants and animals that you have listed in Tables 2.1 and 2.2. Now, group them on the basis of common features. Share and discuss the basis of grouping you have made with other groups in your class.

You will be surprised to see that the basis used by different groups may vary. What do you think are the reasons behind it? Different students might have chosen different common features for the grouping. For example, some students may have chosen the height of plants as the basis for grouping, while others might have chosen presence or absence of flowers as the basis for grouping of plants.

Now, let us learn about how to group plants specifically.

You must have noticed that plants show variation in the features related to stems, leaves, flowers, and more. The stems of different plants vary in thickness, height, and hardness, while the leaves vary in shape, colour, size, and arrangement. You might have tried grouping the plants in Activity 2.3 using one of these features.

You might have also learnt in earlier classes that plants can be grouped into herbs, shrubs, and trees based on their height and types of stem. Let us study the features of plants in more detail and group them on that basis.

Let us do Activity 2.4. Let us go on a nature walk again for some more interesting observations. Look closely at the height of different plants. Are these plants shorter than you, as tall as you, or taller than you? Is the stem brown or green? Touch and feel the stems and try to bend them gently. Can you bend the stem easily, or is it stiff? Take care that the stems do not break. Also, observe from where the branches of the plants arise — whether they arise close to the ground or higher up on the stem. Fill in your observations in Table 2.3. A few examples are already given.

For a mango tree, it is tall, has a brown, hard, thick stem, and branches appear higher up on the stem. This is called a tree. For a rose plant, it is medium in height, has a brown, hard, thin stem, and branches appear close to the ground. This is called a shrub. For a tomato plant, it is short, has a green, tender, thin stem, and branches appear close to the ground. This is called a herb.

Now, what differences do you observe among herbs, shrubs, and trees? How can you group plants as herbs, shrubs, and trees based on the data entered in Table 2.3?

Let me explain this clearly to you, students.

Some plants grow really tall and have hard, thick, brown, and woody stems. Their branches typically start higher up on the stem and away from the ground. These plants are called trees. For example, a mango tree, a banyan tree, a peepal tree — these are all trees.

Some plants are not as tall as trees. These plants often have many brown woody stems that start branching very close to the ground. These stems are hard but not as thick as the stem of a tree. These plants are called shrubs. For example, a rose plant is a shrub. Hibiscus, also known as Gudhal, is also a shrub. Many decorative plants in our gardens are shrubs.

Some plants are typically small with soft and green stems. These are known as herbs. For example, a tomato plant is a herb. Mint, also called pudina, is a herb. Coriander, also called dhania, is a herb. Wheat and rice plants are also herbs when they are young.

Now, there are some more types of plants that you should know about. Some plants with weak stems need support to climb and grow, and are called climbers. For example, a money plant, also called pattha, is a climber. Grape vines are climbers. Some plants creep along the ground and are called creepers. For example, pumpkin is a creeper. Watermelon is a creeper. These plants spread along the ground rather than growing upwards.

Now, what can be other features on the basis of which you can group plants? Let us perform another activity.

Activity 2.5 — Let us compare. Look at the leaves of different plants collected by you during the nature walk. Do you notice any variation in the shape and structure of these leaves?

You may observe thin lines on the leaves of the plants. These are veins. The pattern of veins on the leaf is called venation. What differences do you see in the veins of different leaves?

In some leaves, you can observe a net-like pattern of veins on both sides of a thick middle vein. This pattern is called reticulate venation. For example, leaves of hibiscus exhibit reticulate venation. If you look at a hibiscus leaf carefully, you will see a network of veins spreading out from the middle vein. In some leaves, you may observe that the veins run parallel to each other. This pattern is called parallel venation. For example, the leaves of banana plants and grasses exhibit parallel venation. If you look at a banana leaf or a grass blade, you will see lines running parallel to each other from the base to the tip of the leaf.

Now, do you think that plants can be grouped on the basis of venation present in their leaves? Yes, absolutely! That is one way to group plants.

Now, let us try to explore roots of the plants. Do all plants have roots? Are these roots similar?

Activity 2.6 — Let us find out. Visit an open area where wild herbs and grasses are growing. You may use small herbs for this exercise. Using a khurpi, which is a trowel, carefully dig out a few different herbs without damaging the roots. To do this, you may wet the soil and loosen it. Wash the roots with water and observe them. After you are done observing, make sure to replant the herbs so that they may continue to thrive and grow.

What are the similarities and differences in the roots of the plants collected by you?

Now, let me tell you about the two main types of roots that you will find in plants.

Carefully observe the roots of a mustard plant. The roots of this plant consist of one main root and small side roots arising from it. The main root is called taproot. It goes deep into the soil. Another example of a plant having taproots is hibiscus observed by you in Activity 2.1. Carrot, radish, and turnip are also examples of plants with taproots. Now, look at the roots of a common grass plant. The roots of this plant appear as a bunch of similar-sized thin roots arising from the base of the stem. Such roots are called fibrous roots. Does your collection include any other grasses? What kind of roots do they have? Yes, grasses have fibrous roots.

Now, is there any relation between the type of leaf venation and the type of root of the same plant? Let us find out!

Activity 2.7 — Let us relate and analyse. Collect saplings of five common plants from your school nursery or any other nurseries to plant in your school garden. Examples of such plants can include lemongrass, marigold, sadabahar, which is also called periwinkle, and others. Before planting them, observe their roots and the venation in their leaves. Record your observations in Table 2.4.

For example, lemongrass has parallel venation and fibrous roots. Sadabahar, which is periwinkle, has reticulate venation and a taproot.

Now, do you observe any relation between the leaf venation and types of root in these plants? A sadabahar plant has a taproot and its leaves have reticulate venation. Do other plants with reticulate venation have taproots too? Yes, generally they do! Lemongrass, on the other hand, has fibrous roots and its leaves have parallel venation. Do other plants with parallel venation have fibrous roots too? Yes, generally they do!

So students, here is the general rule — plants with reticulate venation usually have taproots, while plants with parallel venation usually have fibrous roots. This is a very important relationship that you should remember.

Chickpea, which we call chana in India, is another example of a plant with taproots and reticulate venation in leaves. Wheat is an example of a plant with fibrous roots and parallel venation in its leaves.

Now, is there any relation among the seed of a plant, types of root, and leaf venation? Are all seeds similar? Let us find out!

Activity 2.8 — Let us compare. Soak some chickpea and maize seeds in water for two or three days. Remove the seed coat of a chickpea. Now, observe the structure of the chickpea and maize seeds. Are they similar or different?

You would notice that chickpea seeds are split into two parts. Each part is called a cotyledon. Plants that have seeds with two cotyledons are called dicotyledons, which we simply call dicots. Maize has a single thin cotyledon. Plants with such seeds are called monocotyledons, which we simply call monocots.

Now, what relation do you observe among leaf venation, root types, and the number of cotyledons in seeds of a plant?

Here is what we have learned — dicot plants have reticulate venation and a taproot system, while monocot plants have parallel venation and a fibrous root system. This is a very important concept, students. So let me repeat — dicots have two cotyledons in their seeds, reticulate venation in leaves, and taproots. Monocots have one cotyledon in their seeds, parallel venation in leaves, and fibrous roots.

Now, you have learnt about some features used for grouping plants. Now, let us explore the grouping of animals in more detail.

Just like plants, animals too are significantly different from one another. How can we group such a wide variety of animals? What features can you think of to group them? In Activity 2.3, you have already set some bases for grouping animals. Let us explore a few of these in more detail.

Activity 2.9 — Let us find out. You have recorded the movement of a few animals in Table 2.2. You may have also observed how other animals move from place to place. Let us now think about the types of movement in animals.

Different animals have different types of movement. Animals can fly, run, crawl, walk, hop or jump, and so on. They use different body parts for moving from one place to another. They may use wings, legs, and other parts that help them to move.

For example, ants walk and crawl using their legs. Goats walk and jump using their legs. Pigeons walk and fly using their legs and wings. Houseflies walk and fly using their legs and wings. Fish swim using their fins. Birds fly using their wings. Snakes crawl using their body. Frogs hop using their strong hind legs. Kangaroos jump using their powerful hind legs.

So, we can group animals based on how they move and which body parts they use for movement. Some animals use legs, some use wings, some use fins, some use their body — there is so much variety!

Now, before we move on, let me tell you about some amazing Indian scientists who have contributed to the study of biodiversity.

Janaki Ammal was an Indian botanist who was dedicated to environmental work and helped to document and preserve India's rich plant biodiversity. She played a key role in the 'Save Silent Valley' movement. As the head of the Botanical Survey of India, she initiated programmes to document the plant diversity of India. She was born in 1897 and passed away in 1984. She was a pioneer in her field and inspired many young scientists.

Now, there is also a success story about the Save Silent Valley movement. This is a real story of a forest in the Palakkad district of Kerala. It is about preserving the untouched beauty of a moist evergreen forest and its rich biodiversity. The now-famous Silent Valley was saved by a remarkable movement led by common people who were not even residing in the vicinity of the forest. The battle against the proposal of a hydroelectric dam across the Kunthipuzha river persisted for 10 years. At that time, people used all possible available means, such as widespread awareness programmes, letters to editors, articles in newspapers, seminars, and petitions and appeals in court. The movement was successful in saving the Silent Valley. This shows how important it is for all of us to work together to protect our biodiversity.

Now, students, let us move on to Section 2.3 — Plants and Animals in Different Surroundings.

You might have observed during nature walks that different animals live in different surroundings. Does the movement of these animals depend upon their surroundings? Let us consider fishes and goats as examples.

Fishes live in water. They have streamlined bodies and fins for movement in water. Goats live in grassy areas and move with the help of legs. The sizes and shapes of animals also differ from one another.

Activity 2.10 — Let us compare and analyse. Look at Table 2.6. Recreate a similar table on the blackboard. List the names of plants and animals you or your classmates have observed in the regions given in the table or already know about. A few examples are given. You can add more.

For example, in the desert, we have camels and cactus plants. On the mountains, we have deodar trees and mountain goats. In the ocean, we have fish and whales. In the forest, we have lions and tigers.

What are your observations regarding plants and animals found in various regions?

You might observe that the plants and animals found in one kind of region are different from those found in another kind of region. This is because different regions have different environmental conditions, and plants and animals adapt to those conditions.

During a discussion in the classroom, Alex recalls that he observed cactus plants with thick and fleshy stems in the deserts of Rajasthan. Maya shares that she saw deodar trees in the Himalayas of Himachal Pradesh. These trees are conical in shape and have flexible and sloping branches.

Notice that these two types of plants found in different regions are different from each other. Why is it so? Why does the biodiversity of a region vary from that of another?

There is very little water available in the deserts. A hot desert is typically very hot during the day and very cold at night. Therefore, you will find plants and animals in these areas that can tolerate and survive both the hot conditions during the day and cold conditions at night. The fleshy stems of plants found in the desert can store water and help them tolerate the hot conditions in these places. That is why cacti have thick, fleshy stems — they store water for the dry season!

The mountains in extremely cold regions experience frequent snowfall. In order to survive in such conditions, some of the trees have the ability to let the snow slide off easily. Conical shape and sloping branches of deodar trees enable them to do so easily. The snow simply slides off the tree, preventing it from breaking under the weight of snow.

Now, look at the images of a camel from the hot desert of Rajasthan and a camel from the cold desert of Ladakh. What are the differences you observe between them? What advantages do these differences provide to these camels?

The camel of the hot desert has long legs with wide hooves. The long legs and wide hooves help these camels to walk on the sandy desert without sinking into the sand. On the other hand, the height and legs of camels of a cold desert are comparatively shorter than those found in a hot desert. These short legs allow them to walk easily in mountainous regions.

In deserts, food is not available easily. Camels store food in their humps. Camels found in the hot desert have one hump each that helps them to survive during the scarcity of food. Camels found in the cold desert have two humps each. These two humps shrink in late winters because there is not much food available in the cold desert and they have to use food stored in their humps during that time. Moreover, they grow long hair from head to neck, which help them survive the cold winters of Ladakh.

Other features that help camels survive in the desert include — they excrete small amounts of urine, their dung is dry, and they do not sweat. As camels do not lose much water from their bodies, they can survive for many days without drinking water. This is truly amazing adaptation!

Now, Maya talks about seeing plants with beautiful bright flowers, rhododendrons, in the Shola forests of Nilgiris. Here, rhododendrons are of shorter height and have smaller leaves to survive through the heavy winds on mountain tops. However, Pema, who is from Sikkim, mentions that she has observed rhododendrons in the nearby mountains to be taller. So, even plants such as rhododendrons may exhibit different features in different regions to survive the conditions of those regions.

Sagar tells his classmates that he went to the Andaman and Nicobar Islands with his parents for a special event. He saw huge whales and colourful fish in the ocean. His father explained that the streamlined body of fish helps them to swim in water.

Now, students, we have learnt that the plants and animals living in a particular region have special features that make them fit to survive there. The special features that enable plants and animals to survive in a particular region are called adaptations. So remember — adaptations are special features that help organisms survive in their particular environment.

The shape of the deodar tree and the height of the rhododendron are adaptations that enable them to survive in the mountainous regions.

The place where plants and animals live is called their habitat. For example, the habitat of sea turtles is the sea or the ocean. The habitat of a camel is the hot or the cold desert, and the habitat of a rhododendron is the mountains. The habitat of plants and animals provides them food, water, air, shelter, and other needs for their survival. Many types of plants and animals may share the same habitat. Habitat plays an important role in shaping the biodiversity of a region.

Now, what are the different ways in which you can group plants and animals based on their habitats? One way is to group them into those that live on land and those that live in water.

The plants and animals that live on land are said to live in terrestrial habitats. Some examples of terrestrial habitats are forests, deserts, grasslands, and mountains.

The plants and animals that live in water are said to live in aquatic habitats. Some examples of aquatic habitats are ponds, lakes, rivers, and oceans.

Some animals, such as frogs, can live in water as well as on land. These are called amphibians. Amphibians are animals that can live both in water and on land. Frogs, toads, and salamanders are examples of amphibians.

Now, what would happen if the habitat of a plant or an animal is damaged? What would happen if a goat does not get grass to eat? Can a fish survive without water? Obviously not! If habitats are damaged, plants and animals lose their homes, food, and other resources they need to survive.

Check with your parents, grandparents, and neighbours to know about the plants, birds, insects, or any other animal they used to see frequently in their childhood but do not see as often now. These changes often happen when habitats are damaged. The damage to habitats of plants and animals results in loss of their homes, food, and other resources. This leads to the loss of biodiversity.

The population of the Bengal Tiger, Cheetah, and Great Indian Bustard has declined in India due to loss of natural habitats caused by human activities. The Government of India has initiated several projects to conserve our biodiversity. Project Tiger was initiated in 1973 to protect the declining population of the Bengal Tiger. The Cheetah Reintroduction Project was initiated in 2022 to restore the population of the Cheetah. Similarly, habitats of the Great Indian Bustards have been declared as Protected areas in the states of Gujarat, Rajasthan, and Maharashtra.

Now, let me tell you about traditionally protected forests called Sacred Groves. Sacred groves are undisturbed patches of forests. Their sizes may vary from quite small to very large. Sacred groves are found all over India. They are home to different kinds of plants and animals, including numerous medicinal plants. These are protected by the local community and no one is allowed to harm any animals and cut trees in these groves, or disturb the area. This way, sacred groves are a community protected treasure of biodiversity. Find out about the sacred groves in your region.

We must protect biodiversity to ensure our planet is full of life, helping plants and animals to survive and thrive.

Now, let me tell you about another famous Indian scientist — Salim Ali. He was born in 1896 and passed away in 1987. He travelled across India to observe diversity in birds. He prepared a list of birds and documented their travel routes and habitats. He recorded the regions with high diversity of birds and took measures to conserve these regions. Keoladeo National Park in Bharatpur, Rajasthan and Ranganathittu Bird Sanctuary in Mandya, Karnataka are examples of regions he preserved. He wrote a landmark series of 10 books on birds of the Indian Subcontinent. He is referred to as the Birdman of India. He was awarded Padma Vibhushan in 1976. He is truly an inspiration for all of us!

Now, students, we have covered all the main concepts in the chapter. Let me now solve all the exercises for you.

Question 1: Here are two types of seeds. What differences do you find among the roots and leaf venation of their plants?

The two seeds are wheat and kidney beans.

Wheat is a monocot plant. It has fibrous roots and parallel venation in its leaves.

Kidney beans are dicot plants. They have taproots and reticulate venation in their leaves.

So the main differences are — wheat has fibrous roots with parallel venation, while kidney beans have taproots with reticulate venation.

Question 2: Names of some animals are given below. Group them based on their habitats. Write the names of aquatic animals in the area marked 'A' and terrestrial animals in the area marked 'B'. Enter the names of animals living in both habitats in part 'C'.

The animals are: Horse, Dolphin, Frog, Sheep, Crocodile, Squirrel, Whale, Earthworm, Pigeon, Tortoise

Let me explain this to you.

Let me explain this to you.

Aquatic animals are those that live in water. These include Dolphin and Whale.

Terrestrial animals are those that live on land. These include Horse, Sheep, Squirrel, Pigeon, and Earthworm.

Now, some animals can live both in water and on land. These include Frog, Crocodile, and Tortoise. Frogs are amphibians — they can live both in water and on land. Crocodiles and tortoises can also live in both habitats — they spend time in water as well as on land.

So, in area A (Aquatic), we have Dolphin and Whale. In area B (Terrestrial), we have Horse, Sheep, Squirrel, Pigeon, and Earthworm. In area C (Both), we have Frog, Crocodile, and Tortoise.

Question 3: Manu's mother maintains a kitchen garden. One day, she was digging out radish from the soil. She told Manu that radish is a kind of root. Examine a radish and write what type of root it is. What type of venation would you observe in the leaves of radish plant?

Radish is a taproot. It has one main root that goes deep into the soil, with smaller side roots coming out from it.

Since radish is a dicot plant (it has two cotyledons in its seed), it would have reticulate venation in its leaves.

Question 4: Look at the image of a mountain goat and a goat found in the plains. Point out the similarities and differences between them. What are the reasons for these differences?

The mountain goat and the plains goat are both goats, but they have some differences because they live in different environments.

Similarities: Both are goats, they both have legs for walking, they both eat grasses and leaves, and they both belong to the same species.

Differences: The mountain goat has shorter legs and a more compact body. It may have thicker fur or hair to protect it from the cold. The plains goat has longer legs and is adapted to walking on flat ground.

The reasons for these differences are adaptations. The mountain goat has adapted to survive in cold, mountainous regions. Its shorter legs help it climb and walk on rocky terrain. Its thicker coat protects it from the cold. The plains goat is adapted to live in grasslands and flat areas, so it has longer legs for walking longer distances to find food.

Question 5: Group the following animals into two groups based on any feature other than those discussed in the chapter — cow, cockroach, pigeon, bat, tortoise, whale, fish, grasshopper, lizard.

Let me think of different ways to group these animals. One way is to group them based on whether they have hair or feathers or scales.

Animals with hair or fur: Cow, Bat, Whale Animals with feathers: Pigeon Animals with scales: Fish, Lizard, Tortoise Animals with exoskeletons: Cockroach, Grasshopper

Another way is to group them based on their body temperature — whether they are warm-blooded or cold-blooded.

Warm-blooded animals (they can maintain their body temperature): Cow, Pigeon, Bat, Whale Cold-blooded animals (their body temperature changes with the environment): Cockroach, Fish, Grasshopper, Lizard, Tortoise

You can choose any logical grouping based on common features!

Question 6: As the population grows and people want more comfortable lives, forests are being cut down to meet various needs. How can this affect our surroundings? How do you think we can address this challenge?

This is a very important question about environmental conservation.

Cutting down forests can have many negative effects: - Loss of habitat for many animals and plants, leading to a decrease in biodiversity - Soil erosion — tree roots hold the soil together, and without trees, soil can wash away - Climate change — trees absorb carbon dioxide, and cutting them down increases carbon dioxide in the atmosphere - Reduced rainfall — trees help in the water cycle and bring rainfall - Loss of medicinal plants and other resources that we get from forests

To address this challenge, we can: - Plant more trees and participate in tree plantation drives - Use paper and other forest products wisely and sparingly - Create awareness about the importance of forests - Support and participate in conservation efforts - Reduce our consumption of products that require cutting down forests - Support sustainable development practices

Question 7: Analyse the flowchart. What can be examples of 'A' and 'B'?

The flowchart shows: Plant → Yes → Does it have leaves? → Yes → Does it have reticulate venation? → B → Yes → A

So, if a plant has leaves and has reticulate venation, then it is B. If it has leaves but does not have reticulate venation, then it is A.

Since plants with reticulate venation typically have taproots and are dicots, B would be a dicot plant. Examples of B could be hibiscus, rose, or any dicot plant.

Since plants with parallel venation are typically monocots and have fibrous roots, A would be a monocot plant. Examples of A could be grass, wheat, rice, or banana.

Question 8: Raj argues with his friend Sanjay that "Gudhal (hibiscus) plant is a shrub." What questions can Sanjay ask for clarification?

Sanjay can ask several questions to clarify:

- How tall is the hibiscus plant? Is it shorter than you, as tall as you, or taller than you? - Where do the branches arise — close to the ground or higher up on the stem? - Is the stem hard or soft? Is it woody? - Is the stem brown and thick, or green and thin?

Based on the answers to these questions, Sanjay can determine whether the hibiscus plant is a shrub, a tree, or a herb. Remember, shrubs are medium-sized plants with hard stems that branch close to the ground.

Question 9: Based on the information in the table, find out examples of these plants for each group.

The table shows: Group A: Dicot, Taproot — we need to give examples Group B: Monocot, Fibrous roots — we need to give examples

For Group A (Dicot with taproot): Examples include hibiscus, rose, mango, pea, gram, and bean plants. These are dicot plants, so they have two cotyledons in their seeds, and they have taproots and reticulate venation.

For Group B (Monocot with fibrous roots): Examples include wheat, rice, maize, grass, and banana plants. These are monocot plants, so they have one cotyledon in their seeds, and they have fibrous roots and parallel venation.

Now, part (a) asks: What other similarities do plants of group A have? Plants in Group A (dicots) have reticulate venation in their leaves, two cotyledons in their seeds, and taproots. Their flowers usually have parts in multiples of 4 or 5.

Part (b) asks: What other similarities do plants of group B have? Plants in Group B (monocots) have parallel venation in their leaves, one cotyledon in their seeds, and fibrous roots. Their flowers usually have parts in multiples of 3.

Question 10: Observe the labelled part of a duck in the picture given below. What differences do you observe in the feet of the duck compared to the other birds? Which activity would the duck be able to perform using this part?

The duck has webbed feet. Unlike the feet of a pigeon, which have separate toes, the duck's toes are connected by a web of skin. This webbed feet structure helps the duck to swim efficiently in water. The web acts like a paddle when the duck kicks its feet in water, allowing it to move smoothly. So, the duck would be able to swim very well using its webbed feet!

Now, students, let me also tell you about the Learning Further activities. These are additional activities that will help you learn more about biodiversity:

- Read about one Indian scientist or a wildlife biologist who is working towards protection of India's biodiversity. Prepare a brief report. - Explore the contributions of Divya Mudappa, Usha Lachungpa, Ghazala Shahabuddin, Nandini Velho, Vidya Athreya, Uma Ramakrishnan, and Divya Karnad towards biodiversity in India. Prepare a report of the work done by any three of them. - Label the plants in your school with their local names with the help of your teacher or the gardener. List them in your notebook. - With the help of your teacher, plan a field visit or a nature walk. Record your observations. Prepare a class biodiversity register by consolidating the observations and notes of all the students taken during the field visit or nature walk. - Find out about Project Tiger and other similar projects initiated in India to protect our biodiversity. Prepare a presentation for your class. - Divide your class into groups of six students each. Initiate a discussion in the class on how you can protect biodiversity around you. Prepare a group-wise report that includes suggestions given by members of each group. - Interact with elders in your family or neighbourhood to find out various plants and animals that they see now but were not seen earlier and vice-versa. Collect pictures of these plants and animals and paste them in a scrapbook. Find out more about them from your teacher.

Now, students, we have covered the entire chapter! Let me give you a complete summary of everything we have learned.

SUMMARY:

We are surrounded by a large variety of plants and animals. Such variety of plants and animals is a part of biodiversity.

Plants and animals can be grouped on the basis of similarities and differences among them.

Plants have similarities and differences based on features associated with roots, stems, leaves, flowers, and so on.

The method of arranging things into groups based on their common features is called grouping.

Plants can be grouped into herbs, shrubs, and trees based on their heights, types of stem, and branching patterns. Herbs are small plants with soft green stems. Shrubs are medium-sized plants with hard stems that branch close to the ground. Trees are tall plants with hard, thick, woody stems that branch higher up.

Plants can also be grouped as dicotyledons (dicots) and monocotyledons (monocots) based on the number of cotyledons in their seeds. Dicots have two cotyledons, while monocots have one cotyledon.

Monocots generally exhibit parallel venation in their leaves and possess fibrous roots, while dicots typically exhibit reticulate venation in their leaves and possess taproots.

Animals have different types of movement that can be a basis for their grouping. Some animals fly, some crawl, some walk, some swim, and some hop.

Biodiversity of different regions varies because of distinct environmental conditions.

The special features that enable plants and animals to survive in a particular region are called adaptations.

The place where plants and animals live is their habitat.

Based on their habitats, animals and plants can be grouped as terrestrial (living on land) and aquatic (living in water). Some animals like frogs can live in both habitats and are called amphibians.

Due to damage of their habitats, plants and animals lose their homes, food, and other resources, resulting in the loss of biodiversity.

We must protect biodiversity to ensure that our planet is full of life, helping plants and animals to survive and thrive.

Now, students, I want you to remember that every plant and animal around you is special and has a role to play in nature. We must respect and protect all living beings. Thank you for listening so patiently. Do revise this lesson and try to observe the plants and animals around you with new eyes. Good luck!