Diversity in Plants and Animals Around Us PDF

2.1 Diversity in Plants and Animals Around Us Activity 2.1: Let us explore and record  Plan for a nature walk with your teacher to a park or a nearby forest.  While on the nature walk, observe different plants, ins...

2.1 Diversity in Plants and Animals Around Us Activity 2.1: Let us explore and record  Plan for 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.  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.  Record your observations in Table 2.1 about the features of stems, leaves, flowers and anything interesting in various plants. Some examples have been given for you in Fig. 2.1 and Table 2.1. (a) Grass (b) Tulsi (Holy Basil) (c) Hibiscus (Gudhal) Fig. 2.1: Examples of different features of some plants Table 2.1: Observations of different plants around us Local Leaves (shape/ Any other S. name of Stem arrangement of Flowers observations Diversity in the Living World no. plant leaves) and features A single leaf grows Common Soft and alternatively from 1. grass thin Green leaves different points on the stem Arrangement of a Hard pair of leaves in Pinkish 2. Tulsi and thin purple the opposite directions 11 3. Hibiscus Hard  Hard Leaves with 4. Neem and smooth thick surfaces 5. Any other  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—  tall/short, hard/soft stem  different shapes of leaves and their arrangement on the stem or branches  flowers varying in colour, shape, and scent Now, 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 ways they move around in Table 2.2. Some examples have been provided for you. Table 2.2: Observations of different animals around us Name of Place where Food they The way Any other the animal they live eat they move observations (local name) around and features Carrying a Crow Tree Insects Fly and walk twig in its beak Nest in soil Leaves, seeds Ant and burrow and insects Have six legs Grasses, Cow leaves Any other Curiosity | Textbook of Science | Grade 6 What are the similarities and differences among the animals that you have observed and recorded in Table 2.2? 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 also have a variety of foods they consume and movements they exhibit. 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. 12  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. Activity 2.2: Let us appreciate  Close your eyes for 30 seconds and think of one plant and one animal that you have closely observed and have 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? 13 The variety of plants and animals found in a particular region contributes to the biodiversity of that region.  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, and so on. Can you think of more such examples? This shows that plants and animals are dependent on each other. 2.2 How to Group Plants and Animals? 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. Activity 2.3: Let us group  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. Group them on the basis of common features. Curiosity | Textbook of Science | Grade 6   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 (See Fig. 2.2). 14  Presence/ Hard/soft Eating Place they absence of stem habits live flowers Fig. 2.2: Some possible criteria of groupings of plants and animals You may have grouped animals based on varied features, such as what they eat, where they live, what colour they are and how they move. What is the importance of grouping? Grouping makes it easier to understand and study plants and animals on the basis of their similarities and differences. You will learn more about the importance of grouping in our daily lives in the chapter, ‘Materials Around Us’. 2.2.1 How to group plants? 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. Activity 2.4: Let us group  Let us go on a nature walk again for some more interesting observations.  Look closely at the heights 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 their stems and try to bend them gently. Can you bend the stem easily, or is it stiff? Take care that 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.  Table 2.3: Grouping of plants based on height and nature of stem S. Name of Height Nature of stem Appearance of Name no. the plant branches of plant Short/ Green/ Tender/ Thick/ Close Higher group Medium/ Brown Hard Thin to the up on Tall ground the stem 1. Mango Tall Brown Hard Thick Yes Tree 2. Rose Medium Brown Hard Thin Yes Shrub 3. Tomato Short Green Tender Thin Yes Herb 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 (Fig. 2.3a). Curiosity | Textbook of Science | Grade 6 (a) Tree (b) Shrub (c) Herb Fig. 2.3: Types of plants  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 (Fig. 2.3b). Some plants are typically small with soft and green stems. These are known as herbs. For example, a tomato plant is a herb (Fig. 2.3c). Some plants with weak stems need support to climb and grow, and are called climbers. Some plants creep along the ground and are called creepers. Activity 2.5: Let us compare  Look at the leaves of different plants collected by you, during the nature walk.  Do you notice the variation in the shape and structure of these leaves? You may observe thin lines on the leaves of the plants (Fig. 2.4a). These are veins. The pattern of veins on the leaf is called venation. What differences do you see in the veins of leaves shown in Fig. 2.4a and Fig. 2.4b? (b) Banana leaf with (a) Hibiscus leaf with (c) Grass leaf with parallel venation reticulate venation parallel venation Diversity in the Living World Fig. 2.4: Leaves showing different types of venation 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 (Fig. 2.4a). In some leaves, you may observe that the veins run parallel. This pattern is called parallel venation. For example, the leaves of banana plants and grasses exhibit parallel venation (Fig. 2.4b and Fig. 2.4c). 17 Curiosity | Textbook of Science | Grade 6 (a) Taproot system in (b) Fibrous root system a mustard plant in common grass Fig. 2.5: Types of roots Observe carefully the roots of a mustard plant in Fig. 2.5a. The roots of this plant consist of one main root and small side roots arising from it. The main root is called taproot. Another example of a plant having taproots is hibiscus observed by you in Activity 2.1. The plant in Fig. 2.5b is 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 (Fig. 2.5b). 18  Is there any relation between the type of leaf venation and the type of root of the same plant? How do we find this 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 (periwinkle), and others.  Before planting them, observe their roots and the venation in their leaves.  Record your observations in Table 2.4. Table 2.4: Types of leaf venation and roots S. no. Name of the Type of leaf Type of root plant venation (fibrous/tap) (reticulate/ parallel) 1. Lemongrass Parallel Fibrous 2. 3. 4. 5. 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? Diversity in the Living World Lemongrass, on the other hand, has fibrous roots and its leaves have parallel venation. Do other plants with parallel venation have fibrous roots too? Generally, plants with reticulate venation have taproots while those with parallel venation have fibrous roots. Chickpea (chana) 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. 19  Is there any relation among the seed of a plant, types of root and leaf venation? Are all seeds similar? Activity 2.8: Let us compare  Soak some chickpea and maize seeds in water for two or three days. Cotyledons  Remove the seed coat of a chickpea. Now, observe the (a) Dicot seed (chickpea) (b) Monocot seed (maize) Fig. 2.6: Dicot and monocot seeds You would notice that chickpea seeds are split into two parts (Fig. 2.6a). Each part is called a cotyledon. Plants that have seeds with two cotyledons are called dicotyledons (dicots). Maize has a single thin cotyledon (Fig. 2.6b). Plants with such seeds are called monocotyledons (monocots). What relation do you observe among leaf venation, root types and the number of cotyledons in seeds of a plant? Dicot plants have reticulate venation and a taproot system while monocot plants have parallel venation and a fibrous root system. 2.2.2 How to group animals? 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. A number of animals are shown in Fig. 2.7. You can add more animals that you may have observed and create a poster on the variety of animals. Which body parts are used by the animals in the poster you created and those in Fig. 2.7 for movement? Diversity in the Living World Fig. 2.7: Diversity in animals  List these animals in Table 2.5.  Note the ways in which these animals move and name the body parts used for movement. Some examples are given in Table 2.5. 21  Table 2.5: Movements in animals and their body parts involved S. Name of the Type of Body parts used no. animal movement for movement 1. Ant Legs 2. Goat Walks and jumps Legs 3. Pigeon Flies Wings 4. Housefly Walks and flies Legs and wings 5. Fish Fins 6. Any other 7. 8. What conclusions can you draw from the data given in Table 2.5? Different animals have different types of movement. Animals can fly, run, crawl, walk, hop or jump, and so on. These animals use different body parts for moving from one place to another. They may use wings, legs, and other parts that help them to move. Here, we have identified animals based on the types of movement and the body parts used for movement. How can we group animals based on their movements? Additionally, many animals differ from each other in shape, size, structure, colour, and other features. Some of these features can also be used to group animals in various ways. Like plants, grouping of animals is important for understanding their diversity. Curiosity | Textbook of Science | Grade 6 Know a scientist Janaki Ammal (1897–1984) was an Indian botanist 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. 22  Success Story—Save Silent Valley Movement This is a real story of a forest in Palakkad district of Kerala. It is about preserving 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. More to know! 2.3 Plants and Animals in Different Surroundings You might have observed during nature walks that different animals live in different surroundings. You have also recorded movement of animals in Table 2.5. Does the movement of these animals depend upon their surroundings? Let us consider fish and goats as examples. Fish live in water. They have streamlined bodies and fins for movement in water (Fig. 2.8a). Goats live in grassy areas and move with the help of legs (Fig. 2.8b). The sizes and shapes of animals also differ from one another. Diversity in the Living World Fins Legs (a) A fish swims in water (b) A goat walks on ground with the help of fins with the help of legs Fig. 2.8: Body parts used by animals for movement 23  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 these regions or already know about. A few examples are given. You can add more. Table 2.6: Animals and plants found in different surroundings S. In the On In the In the Any other no. desert mountains ocean forest 1. Camel Deodar tree Fish Lion 2. Any other 3. What are your observations regarding plants and animals found in various regions? Discuss your observations with your classmates. You might observe from Table 2.6 that the plants and animals found in one kind of region are different from those found in another kind of region. Fig. 2.9: Cactus with thick and fieshy stems in a desert Curiosity | Textbook of Science | Grade 6 During a discussion in the classroom, Alex recalls that he observed cactus plants with thick and fleshy stems in the deserts of Rajasthan (Fig. 2.9). Maya shares that she saw deodar trees in the Himalayas of Himachal Pradesh (Fig. 2.10). These trees are conical in shape and have flexible and sloping branches. Notice that these two types of plants 24 found in different regions are different Fig. 2.10: A deodar tree in the mountains from each other. Why is it so? Why does the biodiversity of a region vary from that of another? Let us find out. 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. 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. You must have understood by now that the biodiversity varies from region to region because of diverse conditions. Look at the images of a camel from the hot desert of Rajasthan (Fig. 2.11) and a camel from the cold desert of Ladakh (Fig. 2.12). What are the differences you observe between them? What advantages do these differences provide to these camels? Hooves Fig. 2.11: A camel living in the hot Fig. 2.12: A camel living in the Hooves desert of Rajasthan cold desert of Ladakh The camel in the hot desert has long legs with wide hooves. Alex shares that his grandmother told him that the long legs and wide hooves help these camels to walk on the sandy desert Diversity in the Living World without sinking into the sand. On the other hand, the height and legs of camels in a cold desert are comparatively shorter than those found in a hot desert. These short legs allow them to walk easily in mountainous regions. 25  In deserts, food is not available easily. Camels store food in their humps. Camels in the hot desert have one hump each that helps them to survive during the scarcity of food. Camels 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. What other features can help camels to survive in the desert? Other students also start sharing their observations. Kashi from Rajasthan says that camels 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. Maya talks about seeing plants with beautiful bright flowers, rhododendrons, in the Shola forests of Nilgiris (Fig. 2.13a). 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 (a) Rhododendron in Nilgiris the nearby mountains to be taller (Fig. 2.13b). So, even plants such as rhododendrons may exhibit different features in different regions to survive Curiosity | Textbook of Science | Grade 6 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 makes it easier for them to swim in water. (b) Rhododendron in Sikkim Fig. 2.13: Different features of 26 rhododendrons in two different regions  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. 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. What are the different ways you can group plants and animals based on their habitats? One way is to group them into Know a scientist Salim Ali (1896–1987) 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 Diversity in the Living World awarded Padma Vibhushan in 1976. 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. 27  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. 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? 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 populations of the Bengal Tiger, Cheetah, and Great Indian Bustard have 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. Curiosity | Textbook of Science | Grade 6 Bengal Tiger Cheetah Great Indian Bustard Do you know? 28  Traditionally Protected Forests: 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 Sacred grove from the Western treasure of biodiversity. Ghats Find out about the sacred More to groves in your region. know! We must protect biodiversity to ensure our planet is full of life, helping plants and animals to survive and thrive. Keywords Adaptation Monocot plants Analyse Amphibians Parallel venation Compare Aquatic Reticulate venation Create Biodiversity Sacred groves. Explore Diversity in the Living World Cotyledon Shrubs Group Dicot plants Taproot Observe Terrestrial Record Fibrous root Relate Habitat Tree Herbs Venation 29  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.  Plants can also be grouped as dicotyledons (dicots) and monocotyledons (monocots) based on the number of cotyledons in their seeds.  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.  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. Curiosity | Textbook of Science | Grade 6  The place where plants and animals live is their habitat.  Based on their habitats, animals and plants can be grouped into terrestrial and aquatic.  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 suvive and thrive. 30