Reviewing Class 8 Science Notes Chapter 12 How Nature Works in Harmony Class 8 Notes regularly helps in retaining important facts.
Class 8 Science Chapter 12 How Nature Works in Harmony Notes
Class 8 How Nature Works in Harmony Notes
Class 8 Science Chapter 12 Notes – How Nature Works in Harmony Notes Class 8
→ Habitats and Ecosystems: Habitats provide conditions for organisms to live, with biotic (animals, plants, microbes) and abiotic (water, air, sunlight, soil) components. Ecosystems form through interactions between these components and can be terrestrial (deserts, forests, grasslands) or aquatic (lakes, ponds, rivers, sea).
→ Elephant-Human Conflict: Deforestation and altered rainfall reduce forest resources, pushing elephants into farms and villages for food (e.g., bananas, sugarcane), causing crop damage and human-wildlife conflict. Wildlife corridors help connect habitats for safe animal movement.
→ Biotic and Abiotic Interactions: Organisms interact with each other (e.g., predation, competition) and abiotic components (e.g., water, sunlight) for survival processes like nutrition and reproduction, maintaining ecosystem balance.
→ Populations and Communities: A population is a group of the same species in a habitat. A community includes multiple populations interacting. Ecosystems encompass communities and their abiotic interactions.
→ Food Chains and Food Webs: Food chains show linear feeding relationships (e.g., Grass → Grasshopper → Frog → Snake → Eagle). Food webs depict interconnected chains. Trophic levels include producers (plants), primary consumers (herbivores), secondary consumers (small carnivores), and tertiary consumers (large carnivores).
→ Ecosystem: An ecosystem is a community of living things (like plants and animals) interacting with each other and their non-living surroundings (like air, water, and soil).
→ Aquatic ecosystem: An aquatic ecosystem is a community of living things (like fish, plants, and tiny organisms).
→ Terrestrial ecosystem: A terrestrial ecosystem is a land-based community of living things (like plants and animals).
→ Human-made ecosystem: A human-made (or anthropogenic) ecosystem is an environment that has been created or significantly changed by people.
Examples: gardens, farms, aquariums, and even cities.
→ Types of Organisms:
- Producers (autotrophs, e.g., plants) create food via photosynthesis.
- Consumers (heterotrophs) include herbivores (eat plants, e.g., deer), carnivores (eat animals, e.g., leopards), and omnivores (eat both, e.g., foxes).
→ Decomposers: Living things like bacteria and fungi (mushrooms), that break down dead plants, animals, and waste into smaller pieces and turn them back into simple nutrients in the soil.
→ Ecosystem Balance: Dynamic balance is maintained through interactions. Disruptions (e.g., pollution, overfishing) cause cascading effects, like pest increases or reduced oxygen in water.
→ Types of Interactions:
- Mutualism: Both benefited (e.g., honeybees and flowers).
- Commensalism: One benefits, the other is unaffected (e.g., orchids on trees).
- Parasitism: One benefits, one is harmed (e.g., ticks on dogs).
- Competition: Organisms compete for resources, regulating population sizes.
→ Human Impact: Deforestation, pollution, and monoculture farming harm ecosystems.. Overuse of synthetic fertilisers and pesticides degrades soil and increases pest resistance. Sustainable practices like organic farming help maintain balance.
→ Ecosystem Services: Ecosystems provide clean air, water, food, medicine, and climate regulation. Mangroves (e.g., Sundarbans) protect against storms and support biodiversity but face threats from deforestation and pollution.
→ Conservation Efforts: Protected areas (e.g., Jim Corbett, Manas National Parks) preserve biodiversity. Wildlife corridors and sustainable farming reduce human-wildlife conflict and environmental damage.
→ Green Revolution: The Green Revolution in India began in the 1960s to increase food production. It used better seeds (HYV), fertilizers, modern tools, and irrigation. This helped India grow more wheat and rice and become self-sufficient in food.
→ Sundarbans: Mangroves protect against storms but are threatened by deforestation and pollution.
→ Frog Legs Export: Over-harvesting bullfrogs increased pests, leading to more pesticide use, prompting a ban.
→ Migratory Birds: Species like Demoiselle Cranes aid pest control and pollination, linking ecosystems.
→ Sustainability: Organic farming, crop diversity, and reduced pesticide use promote soil health and ecosystem stability, as emphasised in ancient texts like Vrkshayurveda.
→ Cascading Effects: Changes in one component (e.g., fewer frogs) impact others (e.g., more insects, increased pesticide use), showing ecosystem interconnectedness.
→ Habitat: The natural environment where an organism lives, providing conditions like food, water, and shelter necessary for survival (e.g., forests, ponds).
→ Ecosystem: A community of living (biotic) and non-living (abiotic) components interacting in a specific area (e.g., a forest or pond ecosystem).
→ Biotic Components: Living organisms in an ecosystem, such as plants, animals, and microorganisms.
→ Abiotic Components: Non-living elements in an ecosystem, such as air, water, sunlight, soil, and temperature.
→ Population: A group of organisms of the same species living together in a specific habitat at a given time.
→ Community: Different populations of organisms living together and interacting in the same habitat.
→ Food Chain: A linear sequence showing the feeding relationships between organisms in an ecosystem (e.g., grass → grasshopper → frog).
→ Food Web: A network of interconnected food chains showing complex feeding relationships in an ecosystem.
→ Trophic Level: The position of an organism occupies in a food chain, such as producers, herbivores, or carnivores.
→ Producers: Organisms, like plants, that produce their food through photosynthesis, forming the base of the food chain.
→ Consumers: Organisms that cannot produce their food and rely on other organisms (e.g., herbivores, carnivores, omnivores).
→ Decomposers: Organisms, like fungi and bacteria, that break down dead matter and recycle nutrients back into the ecosystem.
→ Herbivores: Animals that feed only on plants (e.g., deer, hare).
→ Carnivores: Animals that feed only on other animals (e.g., leopards, vultures).
→ Omnivores: Animals that feed on both plants and animals (e.g., foxes, mice).
→ Mutualism: A relationship where both organisms benefit (e.g., honeybees pollinating flowers).
→ Commensalism: A relationship where one organism benefits and the other is unaffected (e.g., orchids growing on trees).
→ Parasitism: A relationship where one organism benefits at the expense of another (e.g., ticks on dogs).
→ Pollination: The process of transferring pollen from stamens to carpels, often by wind, water, or animals, is essential for plant reproduction.
→ Decomposition: The process by which decomposers break down dead organic matter into simpler substances, recycling nutrients into the soil.
→ Monoculture: It is the practice of growing only one type of crop in a large area.
→ A habitat is a place that provides the right conditions for an organism to live and grow.
→ Habitats have biotic components (plants, animals, microbes) and abiotic components (air, water, soil, temperature).
→ The interaction between biotic components and abiotic components in an area forms an ecosystem.
→ Ecosystems can be terrestrial (forests, grasslands, deserts) or aquatic (ponds, lakes, seas, oceans).
→ Organisms are often classified as producers (plants), consumers (herbivores, carnivores, omnivores), and decomposers (bacteria, fungi).
→ Producers make their food, while consumers eat plants or animals. Decomposers break down dead matter and recycle nutrients.
→ Food chains depict who eats whom in an ecosystem, and food webs show how these chains are interconnected. The positions that different organisms occupy in a food chain are called trophic levels.
→ Some organisms live in relationships, like mutualism (both benefit), commensalism (one benefits, the other is unaffected), and parasitism (one benefits, one is harmed).
→ The benefits that ecosystems offer are crucial for human survival and well-being. They provide clean air, water, food, medicine, and climate regulation.
→ Human activities like pollution, deforestation, habitat loss, climate change, invasive species, and overexploitation of natural resources threaten ecosystems. Protecting them through efforts, such as conservation in national parks and sanctuaries, is vital.
In several parts of India, particularly in states like Odisha, Jharkhand, West Bengal, Assam, and Chhattisgarh, elephants often enter farms and villages. When vegetation is scarce and waterholes dry up in their natural habitat, elephants may wander into nearby farms or plantations in search of food like bananas and sugarcane. This can lead to crop damage and, at times, even harm people and domestic animals.
Changes in rainfall and temperature affect vegetation. Cutting down trees for constructing roads and buildings makes it worse. This leads to the shrinking and drying of forests, the natural home of animals. When forests cannot support wildlife, animals tend to move into human habitats. Elephants are adapted to forest life, but sudden changes make it hard for them to survive. Wildlife ecologists have identified and marked corridors in many parts of the country to allow safe movement of animals. These corridors correct forest habitats, enabling wildlife such as elephants to travel in need between large forest areas without coming into conflict with human settlements. This chain of events shows how closely nature’s elements are connected. To understand such interconnections, we must study the components of our environment.
How Do We Experience and Interpret Our Surroundings? Class 8 Notes
You have learnt in Curiosity, Grade 6 chapter ‘Diversity in the Living World’ that different habitats have different kinds of plants and animals. A habitat is simply a place where an organism lives. It could even be just the bark of a tree. The plants and animals interact with each other and adapt to survive in the surrounding conditions they live. Explore two nearby habitats and identify both the living organisms and the non-living components in each.
Activity 1: Let us explore
Caution: Explore the habitat in groups with your teacher.
Identify two habitats in your surroundings. These could be any two of the following:
a pond, a forest, an agricultural farm, or even a large tree like a banyan, mango, or pilkhan (white fig) tree.
List the living beings and non-living things that you observe in these habitats. Record your observations in Table 1.
What common characteristics do you observe in the two habitats in Activity 1? The similarities are that both habitats have living beings as well as non-living things. However, the types of living beings are different, and the non-living things also vary. The living beings you have recorded in Table 1 are termed as the biotic components, and non-living things as the abiotic components of a habitat. Have you wondered why some organisms live on land while others live in water? Every organism needs specific conditions to survive. From this activity, you can see that different habitats offer different living conditions.
In Activity 1, you listed fish as a biotic component of the pond. How do fish survive in a pond? A pond provides food, oxygen, shelter, and space to grow conditions essential for the survival of organisms. Fish obtain their biotic needs, such as food, from small plants and animals, and their abiotic needs, such as oxygen, from water. Other living beings also inhabit the pond, such as frogs, freshwater turtles, snakes, dragonflies, mosquitoes, snails, and ducks, along with plants like algae, diatoms, duckweeds, and lotus. They all interact with the other living beings and non-living things present in the places where they grow and thrive.
Each habitat has its biotic components and physical conditions: air, sunlight, water, temperature, and soil. Different organisms living in the same habitat may use the resources in different ways. A forest might be warm during the day and cool at night. A snake that comes out at night and a rodent active during the day both live in the same habitat, but they face different conditions. This is how living organisms coexist in harmony in the same habitat.
Who All Live Together in Nature? Class 8 Notes
You have observed fish in a pond in Activity 1. Did you see only a single fish? Most likely, you may have seen many fish of the same kind. This group of fish of the same kind living together in a pond habitat is called a population of that particular fish. In this way, we can observe and record populations of different kinds of organisms in a single habitat.
Activity 2: Let us record
We can understand the population of a particular type of plant by counting them at a given place and time. Divide students into four to five groups. Each group may identify any two organisms, plant(s) or animal(s). Mark an area of 1 m × 1 m in your school garden. Identify four organisms in this area, and count their numbers. Record the number of the organisms in Table 2. Compile the data from all groups.
In the given example, there is a population of 20 plants, and there are only 5 plants in the same 1 × 1 m2 area. From Activity 2, we can explain that the population is a group of the same type of organisms in a habitat at a given time. Can a habitat have only one type of living organism? What might happen then? If all organisms are the same, they would have the same requirements for food, water, and space, leading to competition and possible scarcity of resources. What else do you think could happen? In Activities 1 and 2, you observed that different groups of organisms live together in a habitat. A community comprises different populations sharing the same habitat. The biotic components of a habitat, such as the plants, animals, and microorganisms, together form the community. These organisms interact and depend on one another for survival.
You may have seen brightly coloured flowers blooming around you. Have you ever looked closely at their parts? A flower has a stalk, green leafy structures called sepals, coloured petals, and two reproductive parts. Carpels (female) and stamens (male). Stamens burst, releasing yellow dust like pollen grains. Wind, water, insects, bats, and birds help carry pollen from the stamens to the carpels of the same and different flowers. This process is called pollination. It is essential for the formation of fruits and seeds.
Does Every Organism in a Community Matter? Class 8 Notes
Let us find out the role of different organisms in a community.
Activity 3: Let us read
Researchers conducted a study to see how fish in ponds affect seed production in the plants nearby. They observed two ponds, A with fish and a large number of flowering plants around it, and B without fish and fewer flowering plants around it. Think of a reason for these observations.
Compare the number of dragonflies, bees, and butterflies in both ponds. Do you find any relationship between the number of dragonflies and bees/butterflies? We observed that in Pond A (with fish), the number of dragonflies was less compared to Pond B. Why?
Fish eat dragonfly larvae, so ponds with fish have fewer dragonflies. Dragonflies usually eat flies, bees, and butterflies. With fewer dragonflies, more bees, flies, and butterflies were found. These insects help pollinate flowers from the nearby areas, moving pollen from one flower to another, which helps plants produce seeds. So, flowers near ponds with fish may produce more seeds than those near ponds without fish.
What does this study show? How does the population of fish in a pond affect the seed production in nearby plants? This study shows how biotic components (fish, dragonflies, pollinators, plants) and abiotic components (temperature, water, nutrients) interact with and affect each other. Similarly, can overfishing by humans change this balance? How do you think it may affect the living and non-living parts of the habitat?
What Are the Different Types of Interactions Among Organisms and Their Surroundings? Class 8 Notes
In Curiosity, Grade 7, you learn about how plants and animals need air, water, soil, and sunlight to grow. Living organisms, or the biotic community, depend on non-living things, that is, abiotic components, for their survival. Plants and animals also depend on each other for nutrition, respiration, and reproduction. These are interactions among the biotic components. Both types of interactions among biotic components and between biotic and abiotic components are important for survival in any habitat.
Look at the Figure, and try to identify interactions among biotic components, and between biotic and abiotic components based on your learnings till now.
Activity 4: Let us relate and identify
Based on the given criteria, identify and describe the interactions between biotic and abiotic components shown in the Figure.
- Criterion 1: Interactions between abiotic and biotic components. These may influence life processes like nutrition, respiration, and reproduction in biotic components.
- Criterion 2: Interaction between two abiotic components may influence the physical characteristics of a habitat.
- Criterion 3: Interaction among the biotic components. These may influence the availability of resources needed for life processes like nutrition, respiration, and reproduction.
Relate your learning to your observations. Record your observations in Table 3 at the appropriate places. Table 3 is filled with examples for your reference.
In Activity 4, you understood that different types of interactions occur within a habitat. From this, you can infer that the biotic components (plants, animals, and microorganisms) and the abiotic components (air, water, soil, sunlight, and temperature) in a habitat interact with each other to form an ecosystem. Organisms in an ecosystem interact with abiotic components for food, shelter, and protection in an ecosystem. Different communities of living organisms interact with abiotic components in an ecosystem. There are two main types of ecosystems in nature. Aquatic ecosystems include ponds, rivers, and lakes, while terrestrial ecosystems include forests, farms, or even large trees like banyan, mango, or pilkhan. Hence, ecosystems can be large or small. Can you find overlapping ecosystems in the Figure?
The figure shows an overlap of different terrestrial and aquatic ecosystems. In this figure, you can see a small river (an aquatic ecosystem) along with mountains, forests, grassland, and farmland, which are examples of terrestrial ecosystems. Farmland is a human-made ecosystem. These ecosystems are interacting with each other at any given point.
In Activity 4, we have seen the importance of the components and their interactions in an ecosystem. For example, sunlight, carbon dioxide, and water are essential for producing food in plants; soil provides a medium and essential nutrients for plant growth; air provides oxygen for respiration in plants as well as animals; water is essential for all living organisms. This shows how living organisms depend on the non-living component of an ecosystem. Just as biotic components depend on abiotic components, abiotic components also depend on biotic components.
For example, plants release oxygen during photosynthesis, roots hold soil in place and prevent erosion, and plants retain soil moisture and help cool the atmosphere. You can identify and study any ecosystem in your surroundings and observe different types of interactions among the biotic and abiotic components. While studying biotic interactions, notice how organisms depend on each other for food.
Activity 5: Let us classify
Observe Figure B, which illustrates a forest ecosystem. Study the picture carefully and spot the organisms listed in Table 4. Using the internet or your school library, find out what these organisms eat. Record your observations in Table 4 by identifying whether each organism feeds only on plants and plant products, only on animals, or on both.
How do plants get their food? As you know, plants make their food through the process of photosynthesis. Thus, they are called producers or autotrophs (auto = self + troph = food). Organisms that cannot produce their food and depend on other organisms for their food are called consumers or heterotrophs (hetero = other + troph = food). List the heterotrophs from Table 4. Organisms that eat only plants are called herbivores, such as deer and hares. Those that eat only animals are carnivores, such as the leopard. Organisms that eat both plants and animals are omnivores, such as crows, foxes, and mice.
Who Eats Whom? Class 8 Notes
In Activity 5, we learn about the feeding relationship among organisms. How can we make linkages with the feeding relationship among organisms in a given ecosystem?
Activity 6: Let us link (relate)
Take an example of a grassland ecosystem. Consider the following organisms that we can spot in a grassland ecosystem: grass, frog, hare, fox, grasshopper, snake, and eagle. In the Figure, a relationship of who eats whom is shown among some of the organisms. Draw the feeding relationships for the remaining organisms by adding arrows, similar to those in Figure.
In the Figure, you can see that the grass is eaten by the hare and the hare is eaten by the fox. This is a representation of a food chain in a grassland ecosystem. Which is another food chain that can be drawn for the organisms given in this activity? One example may be as follows:
Grass → Grasshopper → Frog → Snake → Eagle
The interactions between biotic components based on feeding relationships can be represented in the form of a linear chain. A food chain is a simple sequence showing ‘who eats whom’ in an ecosystem. One such example is given in the Figure.
Activity 7: Let us draw
Figure A represents a crop field with millets, mice, and an eagle. Count the number of each type of organism in Figure A.
Make a table and set a number in the table against each of the organisms. Arrange the numbers in ascending order, consider the highest number at the base and the lowest at the top. Place the mouse, millet, and eagle appropriately in Figure b. What figure do you get? It looks like a pyramid. Complete the pyramid in Figure b.
Each organism in a food chain has a specific position, called a trophic level (troph = food).
- Producers (like green plants) are at the first trophic level.
- Herbivores (like hares and deer) are at the second level.
- Small carnivores (like frogs) are at the third level.
- Large carnivores (like tigers or vultures) occupy the next level.
Activity 8: Let us trace and link
Look at the Figure. Look at the figure and put more arrows for the missing relationship of ‘who eats whom’. How many other organisms might be connected to one organism through a feeding relationship in an ecosystem?
Look at the Figure, and observe the relationship between different food chains in an ecosystem. Are these food chains interlinked? Each of the organisms may be eaten by two or more types of organisms. Thus, in an ecosystem, the food chains are interlinked with each other to form a network, called a food web. You know that living organisms grow, perform many functions, develop, and die. During their life cycle, organisms produce a lot of waste, including dead matter and food waste.
What Happens to Waste in Nature? Class 8 Notes
You may have seen small umbrella-like structures, mushrooms, growing on dead plants or trees during the rainy season.
These are a type of fungi that grow on dead matter. Microorganisms like fungi and bacteria break down complex substances in dead plants and animals into simpler ones. This process returns important nutrients to the soil. You can also find tiny insects, such as beetles and flies, on animal droppings like elephant dung, as they help break it down and recycle nutrients back into the environment. This process is called decomposition, and the organisms carrying out the process are called decomposers or saprotrophs (sapro rotten + trophs = food). Plants grow in soil, and many of the nutrients in soil come from the decomposition process. Thus, decomposers play an important role in recycling nutrients. In nature, nothing is wasted; everything is reused. Does nature waste anything?
India is a country with diverse habitats and seasons. Many migratory birds fly thousands of miles and reach different habitats in India. They migrate from different parts of the world to avoid harsh climates and in search of food. Birds not only enhance the aesthetics of those habitats but also play a significant role in keeping the balance in an ecosystem as pollinators or seed dispersers along the path they migrate. This way, they link two habitats. These birds are predators of insect pests and help farmers to control pest populations, and indirectly help in healthy crop growth.
Migratory birds, including Demoiselle Crane, visit the water body of Khichan village in Jodhpur district during the winter months. Do you know which birds in your area are seen only during winter? Collect postal stamps and covers of migratory birds released by the Indian Postal Department, and collect information about their place of origin and reasons for their migration to different localities in India, and more. Showcase the postal stamps in your science laboratory/school library to popularise migratory birds.
How Does One Change Lead to Another? Class 8 Notes
Look at the Figure. It shows how one small change can lead to many others. For example, many plants in a pond start dying because of pollution. With fewer plants, less oxygen will be produced in the water, which will lead to a drop in the fish population in that water body. Reduction in fish population will have cascading effects, and there will be less number of consumers in the pond. As a result, insects will increase in number. These insects will spread to nearby farmlands. This is how farmers will be compelled to use pesticides to grow their crops, which may again adversely affect the environment. Further consequences may emerge in the form of other environmental issues. What happens when we intervene in nature?
Activity 9: Let us read
In the 1980s, India was a significant exporter of frog legs, especially of the Indian bullfrog (Hoplobatrachus tigerinus) (Figure). This large-scale harvesting led to a decline in frog populations. Since frogs eat insects, their reduced numbers resulted in a rise in agricultural pests. This forced farmers to use more synthetic pesticides, which harmed the environment, soil, and water quality, and affected the overall environmental and human health. The Government of India banned the export of frog legs to prevent further ecological damage.
An ecosystem stays in balance when interactions among organisms and their environment keep populations and resources stable. This balance is dynamic, not fixed, and can be disrupted by natural or human-made changes.
How Do Interactions Maintain Balance in Ecosystems? Class 8 Notes
Besides feeding relationships, organisms also compete for common resources like food, water, physical space, or sunlight. This competition helps control population size and keeps the ecosystem balanced. Without it, one species could multiply too much, causing an imbalance in the ecosystem.
There are other types of relationships, too. Based on the example given in the Figure, what do you observe?
- Mutualism: Both organisms benefit.
For example: Honeybees and flowers. - Commensalism: One organism benefits while the other is not affected.
For example: Orchids on trees. - Parasitism: One organism benefits while the other is harmed.
For example: Ticks on the body of dogs.
These interactions are all part of the complex web of life in an ecosystem.
Asir Jawahar Thomas Johnsingh (A.J.T. Johnsingh) was a famous Indian wildlife biologist who helped us understand forest ecosystems through the eyes of animals. He was a pioneer in studying wildlife through a modern tracking system. His research showed how predators like tigers and leopards rely on prey, such as deer and wild boar, while he was working in Bandipur National Park, Karnataka. He proved that a healthy prey population is key to predator survival. He inspired many youngsters to study wildlife and protect the forests and biodiversity of India.
What are the Benefits of an Ecosystem? Class 8 Notes
We have learnt that biotic components and abiotic components of an ecosystem depend on each other and support various life processes. Humans also benefit from ecosystems. For example, forests provide fresh air, fertile soil, food, fibres, timber, and medicines. Similarly, aquatic ecosystems provide water and food. Ecosystems also offer aesthetic and recreational value. These benefits support our well-being and show how closely nature and humans are connected. However, when we overuse or misuse natural resources, we disturb the balance in nature. Now, let us look at a real-life example of a threatened ecosystem, the Sundarbans.
The Sundarbans have the largest mangrove forests in the world. Located where the Ganges and Brahmaputra Rivers meet between India and Bangladesh, the Sundarbans’ forests and rivers are home to various flora and fauna, many of which are endangered. The Sundarbans protect us by slowing down strong winds and waves during storms and floods. The trees also absorb carbon dioxide from the air and release oxygen. Because of its importance, the United Nations Educational, Scientific and Cultural Organization (UNESCO) declared the Sundarbans a World Heritage Site in 1987. However, the Sundarbans are under a serious threat. Mangrove trees are being cut for fuelwood and farming. Illegal hunting and overuse of forest resources are a threat to the wildlife living there. Pollution from industrial waste and untreated sewage in rivers is also damaging the water and habitat. These human activities disrupt the natural way ecosystems work.
Similarly, other ecosystems across India are also under threat. Problems like deforestation, overuse of natural resources, the spread of invasive species, unsustainable land use, and pollution are damaging forests, rivers, scrublands, wetlands, grasslands, and coastal areas. How can we stop damaging forests, rivers, and wetlands? Think about what actions you and your community can take to protect these important places.
Protected areas are parts of land or water set aside to conserve wildlife and their habitats. India has many protected areas like national parks, wildlife sanctuaries, biosphere reserves, and community conserved areas. These places help protect entire habitats, including endangered animals, birds, and many rare plants. Famous examples include Jim Corbett National Park (Uttarakhand), Manas National Park (Assam), Nilgiri Biosphere Reserve (Western Ghats), Chilika Lake (Odisha), Eaglenest Wildlife Sanctuary (Arunachal Pradesh), Hemis National Park (Leh), Keibul Lamjao National Park (Manipur), Pirotan Island Marine National Park (Gujarat). Protected areas play a big role in saving nature for future generations.
Human-made Ecosystems
Humans have created artificial ecosystems like fish ponds, farms, and parks to meet their needs. When well designed, these can help reduce pollution, support biodiversity, and provide recreational spaces for people. Unlike natural ecosystems, these need human care and management. Can you name any human-made ecosystem in your area?
How do healthy ecosystems serve our farms?
Farming, a major livelihood in India, can become unsustainable if not managed well by applying environment-friendly farming practices. Humans have been practising farming for thousands of years to grow food. As the population grew, our dependence on agriculture increased. Between 1950 and 1965, India faced a food crisis due to low crop production. In the mid-20th century, the use of tractors, machines, synthetic fertilisers, and pesticides helped increase food production. This period is known as the Green Revolution. However, these farming methods are now considered unsustainable because of the overuse of synthetic chemicals, excessive groundwater extraction, and growing only one type of crop for commercial gain. How do these practices harm both the environment and human health? Many scientists believe that overusing pesticides and growing the same type of crop repeatedly on the same land leads to soil degradation. Understanding ecosystems can help us adopt better and more sustainable farming practices.
Activity 10: Let us survey
Visit a nearby farm with your parents or teacher/interact with farmers in your community to find out about the farming practices they adopt. Prepare a list of questions for farmers to find out the pesticides and other farm inputs they use, and whether they reuse or recycle materials to improve their crops. Here are some sample questions:
- How have your farming practices changed over time? And why?
- What effects do you notice when using synthetic fertilisers and pesticides?
- Have you seen any changes in soil health after using these synthetic fertilisers and pesticides?
Interact with farmers based on these questions. Based on your findings, prepare a report. What inference do you draw from your interactions with farmers?
Synthetic fertilisers and pesticides have played a vital role in improving crop production and have helped countries like India become food secure. However, their long-term use can affect the environment and soil health. Overuse of synthetic fertilisers may reduce soil fertility by decreasing friendly microorganisms in soil and lowering organic matter (humus), which helps bind soil particles. Without enough humus, soil becomes prone to erosion. Also, it reduces the population of natural predators, which ultimately increases the population of pests. Heavy irrigation and repeated ploughing can also disturb soil organisms like earthworms and snails, which are important for maintaining ecological balance.
Some pests may develop resistance to pesticides, making them difficult to control. Growing the same crop repeatedly, known as monoculture, can reduce crop diversity and affect pollinators, which are crucial for food production. To make farming more sustainable, some farmers are exploring organic and natural farming methods. These aim to reduce the use of synthetic fertilisers and support sustainable farming, with minimal interference in natural ecosystems. Based on your learning, what practices do you think can help farmers protect the soil, the environment, and our food security for the future?
The ancient text Vrikshayurveda emphasises soil health and nourishment. The text strongly advocates for the continuous nourishment of the soil through organic manure like Kunapa Jala (a liquid fertiliser made from animal and plant waste by the process of fermentation, which breaks complex substances into simpler ones) and other composted materials.