Synonyms
More meanings
Tip: select a single word for meaning & synonyms.
Select multiple words normally to copy text.
Energy Flow and its Balance: NBSE Class 9 Environment
Get summaries, questions, answers, solutions, notes, extras, PDF and guide of Chapter 2 Energy Flow and Its Balance, NBSE Class 9 Environmental Education textbook, which is part of the syllabus of students studying under Nagaland Board. These solutions, however, should only be treated as references and can be modified/changed.
If you notice any errors in the notes, please mention them in the comments
Summary
Energy is the foundation of life on Earth. The Sun is the main source of energy. All living things get their energy directly or indirectly from the Sun. Energy moves through ecosystems in a process called energy flow. This flow happens along food chains and food webs. It follows the laws of thermodynamics and moves in one direction only. Energy flows from the Sun to producers like plants, then to consumers like animals.
Plants are the first step in the energy flow. They use sunlight to make food through photosynthesis. This process stores energy in their cells. Plants also release oxygen as a by-product. Animals that eat plants are called herbivores. They are the second step. Herbivores are also called primary consumers. Animals that eat herbivores are called carnivores. Carnivores are secondary consumers. Some carnivores eat other carnivores. These are tertiary consumers. Decomposers like bacteria and fungi break down dead plants and animals. They return nutrients to the soil.
Energy decreases as it moves up the food chain. Only 10% of energy moves to the next level. The rest is lost as heat. This means higher-level consumers get less energy. Food chains cannot have more than five or six levels because energy runs out. Energy flow helps maintain balance in nature. It shows how all living things depend on each other.
A food chain explains who eats whom in an ecosystem. It starts with producers and ends with decomposers. A food web is made of many interconnected food chains. Food webs show how organisms interact. Nutrients move in cycles. The main cycles are oxygen, carbon, nitrogen, and water. Oxygen is used by animals and released by plants. Carbon moves between living things and the air. Nitrogen is fixed by bacteria and returned to the air. Water moves through evaporation, condensation, and precipitation.
Nature stays balanced when biotic and abiotic parts work together. Biodiversity helps maintain this balance. Human activities like pollution and deforestation can disturb it. Disturbances can harm ecosystems. Protecting nature is important to keep the balance. Steps include protecting habitats and reducing pollution. Understanding energy flow and nutrient cycles helps us care for ecosystems.
Energy flow and nutrient cycles are key to life. Plants, animals, and decomposers all play roles in these processes. Food chains and food webs show how energy moves. Nutrient cycles explain how elements like oxygen, carbon, and nitrogen are reused. Balance in nature depends on these interactions. Humans must take action to protect ecosystems for future generations.
Textbook solutions
Multiple Choice Questions (MCQs)
1. ……………….is the primary source of energy in all ecosystems.
(a) Soil (b) Water (c) Sunlight (d) None of these
Answer: (c) Sunlight
2. Without the transfer of energy there could be no life and no ecosystem.
(a) True (b) False
Answer: (a) True
3. Transfer of energy at trophic levels and linking of trophic levels is called
(a) Food web (b) Food chain (c) Symbiosis (d) None of these
Answer: (b) Food chain
4. Animals that obtain their energy by eating plants only are called
(a) Omnivores (b) Carnivores (c) Herbivores (d) None of these
Answer: (c) Herbivores
Very Short Answer Questions
1. Define food chain.
Answer : A food chain explains which organism eats another organism in the environment. It is a linear sequence of organisms where nutrients and energy is transferred from one organism to the other. It begins with the producer organism, follows the chain and ends with the decomposer organism. The food chain also explains the feeding pattern or relationship between living organisms.
2. What do you understand by food web?
Answer : Several interconnected food chains form a food web. A food web is similar to a food chain but it is comparatively larger than a food chain. Occasionally, a single organism is consumed by many predators or it consumes several other organisms. Because of this, many trophic levels get interconnected and the food chain fails to showcase the flow of energy in the right way. But, the food web is able to show the proper representation of energy flow, as it displays the interactions between different organisms.
3. What is nutrient cycle?
Answer : Nutrient cycling is a cyclic process that encompasses the movement of nutrients from the physical environment to living organisms and back to the environment. Nutrients are present on the earth where they are recycled, transformed into different forms and reutilized.
4. What is hydrological cycle?
Answer : Water is an essential element for life to exist on earth. Water from oceans, lakes, rivers and other reservoirs is continuously converted to vapour by the process of evaporation and transpiration from the surface of plants. Water vapours get condensed and return by precipitation and the cycle continues. The water falling on the ground is absorbed and stored as groundwater.
5. Give a brief description of oxygen cycle.
Answer : Oxygen is essential for life. Aquatic organisms are dependent on oxygen dissolved in water. Atmospheric oxygen is taken up by living organisms in the process of respiration and release carbon dioxide which is used for photosynthesis by plants. Photosynthesis is the main source of oxygen present in the atmosphere. It is required for decomposition of biodegradable waste products.
6. What do you understand by the balance in nature?
Answer : Balance in nature means interaction between biotic and abiotic components in equilibrium. Ecological balance plays a crucial role in an ecosystem. It describes the state in which the various organisms and their habitats interact with each other in a harmonious system. Biodiversity is a key element in maintaining the ecological balance. This delicate balance is based on complex interactions and dependencies between species and their environment. This system is maintained by complex food webs and chains.
Short Answer Questions
1. What do you mean by energy flow?
Answer : Flow of energy that occurs along a food chain is called energy flow. It involves the transfer of energy from one organism to another, primarily through food. This flow is governed by the laws of thermodynamics. It is unidirectional from the Sun to producers and then to consumers, sustaining life.
2. Give two features of the producers in an ecosystem.
Answer : (i) In this stage or level, the sunlight is converted into chemical energy. This energy remains stored in the cells.
(ii) The chemical energy is formed through the process of photosynthesis.
3. Define food web. Give some examples also.
Answer : A food web is similar to a food chain but it is comparatively larger than a food chain. Occasionally, a single organism is consumed by many predators or it consumes several other organisms. Because of this, many trophic levels get interconnected and the food chain fails to showcase the flow of energy in the right way. But, the food web is able to show the proper representation of energy flow, as it displays the interactions between different organisms.
Examples:
(i) Grass → Rats → Hawk
(ii) Grass → Grasshopper → Insects
4. Mention two roles of decomposers in an ecosystem.
Answer : (i) They act as environmental cleaners by decaying dead plants and animals.
(ii) They aid in the recycling of nutrients.
5. What is photosynthesis?
Answer : Photosynthesis is the process in which sunlight is converted into chemical energy. This energy remains stored in the cells. The chemical energy is formed through the process of photosynthesis. The most important by-product of this process is the oxygen which is used by all organisms.
6. What do you understand by loss of energy in trophic levels?
Answer : When energy is transferred from one level to another, only 10% is passed to the next higher trophic level. Remaining 90% is released to the environment. There is a continuous decline in the energy as it transfers from one trophic level another throughout the food chain. It means that longer the food chain, lesser the amount of energy available to the last recipient.
7. Briefly describe the energy flow in first trophic level.
Answer : In this stage or level, the sunlight is converted into chemical energy. This energy remains stored in the cells. The chemical energy is formed through the process of photosynthesis. The most important by-product of this process is the oxygen which is used by all organisms. Plants are the first link of the food web; therefore, they are also called primary producers.
8. Why the flow of energy is important to an ecosystem?
Answer : Energy flow is the phenomenon that is responsible to sustain life on this planet. All the biotic components in this ecosystem need energy for their survival. If the energy flow in an ecosystem is disturbed, then it leads to ecological imbalance. It is vital for all living things in ecosystem to survive and function properly. It helps us to understand who eats whom in nature. More the diversity of organisms more stable the ecosystem is. It shows how all creatures in an ecosystem depend on each other and how changes can affect each other. It helps us to see how human actions are affecting the ecosystem. Understanding the flow of energy in an ecosystem helps us to devise proper conservation techniques to save the ecosystem.
Long Answer Questions
1. Explain the process of energy flow through trophic levels.
Answer: Flow of energy that occurs along a food chain is called energy flow. It involves the transfer of energy from one organism to another, primarily through food. It is unidirectional from the Sun to producers and then to consumers, sustaining life.
First Trophic Level: This is the first stage of energy flow. In this stage or level, the sunlight is converted into chemical energy. This energy remains stored in the cells. The chemical energy is formed through the process of photosynthesis. The most important by-product of this process is the oxygen which is used by all organisms. Plants are the first link of the food web; therefore, they are also called primary producers.
Second Trophic Level: In the second trophic level, many animals and insects feed on the plants. Thus, the energy is transferred from plants to animals eating them. This way the energy is transferred from the first trophic level to the second trophic level. Animals that obtain their energy solely by eating plants are known as herbivores. They are also called the primary consumers because they are the first to consume energy generated by plants or primary producers.
Third Trophic Level: The third trophic level is made by the animals that feed on the herbivores. They are flesh-eating animals and are called carnivores. This way the energy is transferred from the second trophic level to the third trophic level. Animals of this trophic level are called secondary consumers because they are feeding on the herbivores who have already consumed energy from plants.
Fourth Trophic Level: The fourth trophic level is also made up of carnivores. These animals feed on other carnivores. The energy is transferred from the third trophic level to the fourth trophic level. Animals of the fourth trophic level are called the tertiary consumers.
Fifth Trophic Level: The fifth trophic level is made up of decomposers which include microorganisms like bacteria and fungi. They break down the dead and decaying matter into nutrients that can be used again. Decomposition of food, in fact, can take place at other trophic levels also. Thus, they are capable of receiving energy from all types of plants as well as animals. They also supply energy to all the organisms at all levels.
2. No energy transfer is 100% efficient. Discuss.
Answer: When energy is transferred from one level to another, only 10% is passed to the next higher trophic level. Remaining 90% is released to the environment. The primary producers, therefore, receive maximum energy and carnivores at the fourth level receive minimum energy. There is a continuous decline in the energy as it transfers from one trophic level to another throughout the food chain. It means that the longer the food chain, the lesser the amount of energy available to the last recipient. This way the food chain cannot be more than five or six levels. Herbivores, therefore, get more energy than the carnivores.
3. What is food chain? Explain with examples.
Answer: A food chain explains which organism eats another organism in the environment. It is a linear sequence of organisms where nutrients and energy is transferred from one organism to the other. It begins with the producer organism, follows the chain and ends with the decomposer organism. The food chain also explains the feeding pattern or relationship between living organisms. Trophic level refers to the sequential stages in a food chain, starting with producers at the bottom, followed by primary, secondary and tertiary consumers.
Examples of Different Food Chains:
(i) Food chain of a typical Grassland (Terrestrial food chain): Grass → Insects → Frogs → Snakes → Hawk/Otter.
(ii) Forest food chain (Terrestrial food chain): Forest vegetation → Deer → Lion.
(iii) Freshwater food chain (Aquatic food chain): Aquatic plants/phytoplanktons → Small fish → Large fish → Egret.
(iv) Marine (Aquatic) food chain: Bull kelp → Sea-urchin → Gray whale → Orca.
4. What is nutrient cycle? Discuss hydrological cycle in detail.
Answer: Nutrient cycling is a cyclic process that encompasses the movement of nutrients from the physical environment to living organisms and back to the environment. Nutrients are present on the earth where they are recycled, transformed into different forms and reutilized.
Water is an essential element for life to exist on earth. Water from oceans, lakes, rivers and other reservoirs is continuously converted to vapour by the process of evaporation and transpiration from the surface of plants. Water vapours get condensed and return by precipitation and the cycle continues. The water falling on the ground is absorbed and stored as groundwater.
5. Write a detailed note on the ‘balance in nature’.
Answer: Balance in nature means interaction between biotic and abiotic components in equilibrium. Ecological balance plays a crucial role in an ecosystem. It describes the state in which the various organisms and their habitats interact with each other in a harmonious system.
Biodiversity is a key element in maintaining the ecological balance. This delicate balance is based on complex interactions and dependencies between species and their environment. This system is maintained by complex food webs and chains. If this balance is disturbed, whether by human activity or natural events, serious consequences can occur for the entire ecosystem. Disturbances can spread like an echo through the food chains, causing further damage. Pollution, climate change and habitat destruction are just some of the man-made factors that exacerbate these disturbances. Human activities like deforestation or pollution are increasingly endangering this sensitive ecosystem.
Extras
Additional questions and answers
1. What is energy flow?
Answer: Flow of energy that occurs along a food chain is called energy flow. The energy flow of an ecosystem is essential for ecological balance. It involves the transfer of energy from one organism to another, primarily through food.
2. Define trophic level.
Answer: Trophic level refers to the sequential stages in a food chain, starting with producers at the bottom, followed by primary, secondary, and tertiary consumers.
3. What is the role of the Sun in an ecosystem?
Answer: Sun is the ultimate source of energy. All the producers and consumers of an ecosystem take their part of energy directly or indirectly from the sun.
4. State the first law of thermodynamics in relation to energy flow.
Answer: This flow is governed by the laws of thermodynamics.
5. What do you understand by primary producers?
Answer: Plants are the first link of the food web; therefore, they are also called primary producers.
6. Name the process by which plants convert solar energy into chemical energy.
Answer: The chemical energy is formed through the process of photosynthesis.
7. What is the role of decomposers in an ecosystem?
Answer: They act as environmental cleaners by decaying dead plants and animals. They aid in the recycling of nutrients. If they weren’t in the ecosystem, the plants would not get essential nutrients and dead matter and waste would pile up.
8. How does energy transfer from one trophic level to another?
Answer: When energy is transferred from one level to another, only 10% is passed to the next higher trophic level. Remaining 90% is released to the environment.
9. What is the significance of oxygen in an ecosystem?
Answer: Oxygen is essential for life. Aquatic organisms are dependent on oxygen dissolved in water. Atmospheric oxygen is taken up by living organisms in the process of respiration and release carbon dioxide which is used for photosynthesis by plants.
10. Define ecological balance.
Answer: Balance in nature means interaction between biotic and abiotic components in equilibrium. Ecological balance plays a crucial role in an ecosystem. It describes the state in which the various organisms and their habitats interact with each other in a harmonious system.
11. What do you mean by primary consumers?
Answer: Animals that obtain their energy solely by eating plants are known as herbivores. They are also called the primary consumers because they are the first to consume energy generated by plants or primary producers.
12. How is energy lost between trophic levels?
Answer: When energy is transferred from one level to another, only 10% is passed to the next higher trophic level. Remaining 90% is released to the environment.
13. Why is the food chain limited to five or six trophic levels?
Answer: There is a continuous decline in the energy as it transfers from one trophic level to another throughout the food chain. It means that longer the food chain, lesser the amount of energy available to the last recipient. This way the food chain cannot be more than five or six levels.
14. What is an obligate carnivore?
Answer: Animals that must eat meat to thrive are called obligate carnivores.
15. Define detritivores.
Answer: Detritivores include decomposers and detritus feeders. They act as environmental cleaners by decaying dead plants and animals. They aid in the recycling of nutrients.
16. What is a food chain?
Answer: A food chain explains which organism eats another organism in the environment. It is a linear sequence of organisms where nutrients and energy is transferred from one organism to the other. It begins with the producer organism, follows the chain and ends with the decomposer organism.
17. What is a food web?
Answer: Several interconnected food chains form a food web. A food web is similar to a food chain but it is comparatively larger than a food chain. Occasionally, a single organism is consumed by many predators or it consumes several other organisms. Because of this, many trophic levels get interconnected and the food chain fails to showcase the flow of energy in the right way. But, the food web is able to show the proper representation of energy flow, as it displays the interactions between different organisms.
18. What is a nutrient cycle?
Answer: Nutrient cycling is a cyclic process that encompasses the movement of nutrients from the physical environment to living organisms and back to the environment. Nutrients are present on the earth where they are recycled, transformed into different forms and reutilized.
19. Name the four main nutrient cycles.
Answer: The four main nutrient cycles are: Oxygen Cycle, Carbon Cycle, Nitrogen Cycle, Hydrological Cycle or Water Cycle.
20. Define carbon cycle.
Answer: Carbon is the main constituent of all the living cells. Carbon is present mainly as carbon dioxide and methane in the atmosphere. There is a continuous exchange of carbon between biotic and abiotic components by the process of photosynthesis and respiration. Atmospheric carbon dioxide is fixed by plants in the process of photosynthesis. Carbon is released back into the atmosphere by respiration, burning of fossil fuels & auto emissions. Organic carbon from dead and decaying organisms and waste products is released into the atmosphere after decomposition.
21. What is nitrogen fixation?
Answer: Nitrogen fixation is the process in which nitrogen-fixing bacteria convert atmospheric nitrogen into ammonia.
22. How is nitrogen converted into nitrates?
Answer: Nitrogen is converted into nitrates when nitrifying bacteria convert ammonia to nitrate, and atmospheric nitrogen is also converted to nitrates directly by lightning.
23. Define hydrological cycle.
Answer: The hydrological cycle, or water cycle, is the continuous process where water from oceans, lakes, rivers, and other reservoirs is converted into vapor through evaporation and transpiration from plants. Water vapors then condense and return to the ground through precipitation, and the cycle continues.
24. What is condensation in the water cycle?
Answer: Condensation in the water cycle is the process where water vapors get condensed.
25. Define respiration in the carbon cycle.
Answer: Respiration in the carbon cycle is the process by which carbon is released back into the atmosphere.
26. What happens to organic carbon from dead organisms?
Answer: Organic carbon from dead and decaying organisms and waste products is released into the atmosphere after decomposition.
27. What is photosynthesis?
Answer: Photosynthesis is the process by which plants use sunlight to convert carbon dioxide into organic compounds, producing oxygen as a by-product. It is the main source of oxygen present in the atmosphere.
28. What are the main components of a food chain?
Answer: The main components of a food chain are the Sun, producers, consumers, and decomposers.
29. What is the main function of decomposers?
Answer: The main function of decomposers is to act as environmental cleaners by breaking down dead plants and animals, aiding in the recycling of nutrients, and ensuring that essential nutrients are available for plants and other organisms.
30. What do you mean by ecological imbalance?
Answer: Ecological imbalance refers to the disturbance in the balance between biotic and abiotic components in an ecosystem, often caused by human activities or natural events. Such disturbances can spread through food chains, causing further damage and leading to serious consequences for the entire ecosystem.
31. What are the different trophic levels in an ecosystem?
Answer : The different trophic levels in an ecosystem include the first trophic level where sunlight is converted into chemical energy by plants, the second trophic level where herbivores feed on plants, the third trophic level consisting of carnivores that feed on herbivores, the fourth trophic level made up of carnivores feeding on other carnivores, and the fifth trophic level which includes decomposers like bacteria and fungi that break down dead matter.
32. How does energy flow through an ecosystem?
Answer : Energy flow occurs along a food chain and involves the transfer of energy from one organism to another, primarily through food. This flow is governed by the laws of thermodynamics and is unidirectional, starting from the Sun to producers and then to consumers, sustaining life.
33. Why is energy flow considered unidirectional?
Answer : Energy flow is considered unidirectional because it flows from the Sun to producers and then to consumers, sustaining life. It cannot be recycled and moves in one direction only.
34. Explain how the first trophic level functions in an ecosystem.
Answer : In the first trophic level, sunlight is converted into chemical energy through the process of photosynthesis. This energy remains stored in the cells of plants, which are the primary producers. Oxygen, an important by-product of this process, is used by all organisms.
35. What happens at the second trophic level?
Answer : At the second trophic level, many animals and insects feed on plants, transferring energy from the first trophic level to the second. Animals that obtain their energy solely by eating plants are known as herbivores or primary consumers because they are the first to consume energy generated by plants or primary producers.
36. Describe the role of secondary consumers in an ecosystem.
Answer : Secondary consumers are animals that feed on herbivores. They are flesh-eating animals and are called carnivores. This way the energy is transferred from the second trophic level to the third trophic level. Animals of this trophic level are called secondary consumers because they are feeding on the herbivores who have already consumed energy from plants.
37. How do tertiary consumers obtain energy?
Answer : Tertiary consumers obtain energy by feeding on other carnivores. The energy is transferred from the third trophic level to the fourth trophic level. Animals of the fourth trophic level are called tertiary consumers.
38. Why is the energy transfer between trophic levels only 10% efficient?
Answer : When energy is transferred from one level to another, only 10% is passed to the next higher trophic level. Remaining 90% is released to the environment. There is a continuous decline in the energy as it transfers from one trophic level to another throughout the food chain. It means that longer the food chain, lesser the amount of energy available to the last recipient.
39. How do decomposers contribute to the ecosystem?
Answer : Decomposers include microorganisms like bacteria and fungi. They breakdown the dead and decaying matter into nutrients that can be used again. Decomposition of food, in fact, can take place at other trophic levels also. Thus, they are capable of receiving energy from all types of plants as well as animals. They also supply energy to all the organisms at all levels. They act as environmental cleaners by decaying dead plants and animals. They aid in the recycling of nutrients. If they weren’t in the ecosystem, the plants would not get essential nutrients and dead matter and waste would pile up.
40. What are some examples of food chains in different ecosystems?
Answer : Examples of different food chains include:
(i) Food chain of a typical Grassland (Terrestrial food chain): Grass → Insects → Frogs → Snakes → Hawk/Otter.
(ii) Forest food chain (Terrestrial food chain): Forest vegetation → Deer → Lion.
(iii) Freshwater food chain (Aquatic food chain): Aquatic plants/phytoplanktons → Small fish → Large fish → Egret.
(iv) Marine (Aquatic) food chain: Bull kelp → Sea-urchin → Gray whale → Orca.
41. Explain how a food web is more complex than a food chain.
Answer : A food web is similar to a food chain but it is comparatively larger than a food chain. Occasionally, a single organism is consumed by many predators or it consumes several other organisms. Because of this, many trophic levels get interconnected and the food chain fails to showcase the flow of energy in the right way. But, the food web is able to show the proper representation of energy flow, as it displays the interactions between different organisms. When there are more cross-interactions between different food chains, the food web gets more complex.
42. What happens when the ecological balance is disturbed?
Answer : If the ecological balance is disturbed, whether by human activity or natural events, serious consequences can occur for the entire ecosystem. Disturbances can spread like an echo through the food chains, causing further damage.
43. How does human activity affect energy flow in an ecosystem?
Answer : Human activities like deforestation or pollution are increasingly endangering this sensitive ecosystem. Pollution, climate change and habitat destruction are just some of the man-made factors that exacerbate these disturbances.
44. Why is biodiversity important for maintaining ecological balance?
Answer : Biodiversity is a key element in maintaining the ecological balance. This delicate balance is based on complex interactions and dependencies between species and their environment.
45. What is the difference between a food chain and a food web?
Answer : A food chain explains which organism eats another organism in the environment. It is a linear sequence of organisms where nutrients and energy is transferred from one organism to the other. It begins with the producer organism, follows the chain and ends with the decomposer organism. A food web is similar to a food chain but it is comparatively larger than a food chain. When there are more cross-interactions between different food chains, the food web gets more complex.
46. How does the carbon cycle function in nature?
Answer : Carbon is present mainly as carbon dioxide and methane in the atmosphere. There is a continuous exchange of carbon between biotic and abiotic components by the process of photosynthesis and respiration. Atmospheric carbon dioxide is fixed by plants in the process of photosynthesis. Carbon is released back into the atmosphere by respiration, burning of fossil fuels & auto emissions. Organic carbon from dead and decaying organisms and waste products is released into the atmosphere after decomposition.
47. What are the main stages of the nitrogen cycle?
Answer : Nitrogen-fixing bacteria fix atmospheric nitrogen to ammonia. Nitrifying bacteria convert ammonia to nitrate. Atmospheric nitrogen gets converted to nitrates directly by lightning. Decomposers breakdown proteins and amino acids of dead and decaying organic matters and waste product. Denitrifying bacteria convert ammonia and nitrates to nitrogen and nitrous oxide.
48. How does nitrogen return to the atmosphere?
Answer : Denitrifying bacteria convert ammonia and nitrates to nitrogen and nitrous oxide. In this way, nitrogen is released back into the atmosphere.
49. Describe the role of water vapour in the hydrological cycle.
Answer : Water from oceans, lakes, rivers and other reservoirs is continuously converted to vapour by the process of evaporation and transpiration from the surface of plants. Water vapours get condensed and return by precipitation and the cycle continues.
50. Why is the oxygen cycle essential for life?
Answer : Oxygen is essential for life. Aquatic organisms are dependent on oxygen dissolved in water. Atmospheric oxygen is taken up by living organisms in the process of respiration and release carbon dioxide which is used for photosynthesis by plants. Photosynthesis is the main source of oxygen present in the atmosphere. It is required for decomposition of biodegradable waste products.
51. How do humans impact the nutrient cycles?
Answer : Human activities like deforestation or pollution are increasingly endangering this sensitive ecosystem. Pollution, climate change, and habitat destruction are some of the man-made factors that exacerbate disturbances in the nutrient cycles. These disturbances can spread like an echo through the food chains, causing further damage.
52. What is the relationship between energy flow and biodiversity?
Answer : More the diversity of organisms, more stable the ecosystem is. It shows how all creatures in an ecosystem depend on each other and how changes can affect each other. Understanding the flow of energy in an ecosystem helps us to devise proper conservation techniques to save the ecosystem.
53. How do autotrophs contribute to the ecosystem?
Answer : Autotrophs, such as phytoplankton, cyanobacteria, algae, and green plants, are the producers in an ecosystem. They convert sunlight into chemical energy through the process of photosynthesis. This energy remains stored in their cells and is transferred to other organisms when they are consumed. The most important by-product of this process is oxygen, which is used by all organisms. Autotrophs form the first link of the food web and are called primary producers because they generate energy that sustains life in the ecosystem.
54. What is the importance of understanding energy flow in conservation efforts?
Answer : Understanding the flow of energy in an ecosystem helps us to devise proper conservation techniques to save the ecosystem. It is vital for all living things in the ecosystem to survive and function properly. It shows how all creatures in an ecosystem depend on each other and how changes can affect each other. More the diversity of organisms, the more stable the ecosystem is. It also helps us to see how human actions are affecting the ecosystem.
55. Explain the term “ecological balance” with an example.
Answer : Balance in nature means interaction between biotic and abiotic components in equilibrium. Ecological balance plays a crucial role in an ecosystem. It describes the state in which the various organisms and their habitats interact with each other in a harmonious system. Biodiversity is a key element in maintaining the ecological balance. This delicate balance is based on complex interactions and dependencies between species and their environment. This system is maintained by complex food webs and chains. If this balance is disturbed, whether by human activity or natural events, serious consequences can occur for the entire ecosystem. Disturbances can spread like an echo through the food chains, causing further damage. Pollution, climate change and habitat destruction are just some of the man-made factors that exacerbate these disturbances. Human activities like deforestation or pollution are increasingly endangering this sensitive ecosystem.
For example, if deforestation occurs, it disrupts the ecological balance as many species lose their habitat, leading to a decline in biodiversity and affecting the entire ecosystem.
56. Why are decomposers an important part of the food web?
Answer : Decomposers are sometimes considered the most important part of the food web because they act as environmental cleaners by decaying dead plants and animals, aid in the recycling of nutrients, and supply energy to all the organisms at all levels. If they weren’t in the ecosystem, the plants would not get essential nutrients, and dead matter and waste would pile up.
57. What are some ways to protect and restore ecological balance?
Answer : It is essential to take measures to protect and restore the ecological balance in order to preserve nature in its natural balance. By protecting and restoring this fragile balance, we can help to preserve the environment and leave nature intact for future generations. It is up to us to use our knowledge and our actions to ensure that the ecological balance is maintained. It is vital that we as a society deepen our knowledge of the interrelationships in nature and take action to protect the ecological balance. Only through targeted action can we preserve the ecosystem in the long term and ensure a sustainable future for generations to come.
58. How do human activities like deforestation affect food chains?
Answer : Human activities like deforestation are increasingly endangering this sensitive ecosystem. Disturbances can spread like an echo through the food chains, causing further damage.
59. Define the term energy flow. Explain why the flow of energy in an ecosystem is considered unidirectional.
Answer : Energy flow is the flow of energy in an ecosystem. The flow of energy in an ecosystem is considered unidirectional because it involves the transfer of energy from one organism to another, primarily through food, and it is unidirectional from the Sun to producers and then to consumers, sustaining life.
60. Explain the first trophic level in an ecosystem. Why are plants considered primary producers?
Answer : The first trophic level is the first stage of energy flow. In this stage or level, the sunlight is converted into chemical energy. This energy remains stored in the cells. The chemical energy is formed through the process of photosynthesis. The most important by-product of this process is the oxygen, which is used by all organisms. Plants are the first link of the food web; therefore, they are also called primary producers.
61. Describe the role of primary consumers in an ecosystem. How do they obtain and transfer energy?
Answer : Primary consumers are animals that obtain their energy solely by eating plants. They are also called herbivores and are the first to consume energy generated by plants or primary producers. In the second trophic level, many animals and insects feed on the plants. Thus, the energy is transferred from plants to animals eating them. This way the energy is transferred from the first trophic level to the second trophic level.
62. Explain the third trophic level in an ecosystem and the role of carnivores in energy transfer.
Answer : The third trophic level is made by the animals that feed on the herbivores. They are flesh-eating animals and are called carnivores. This way the energy is transferred from the second trophic level to the third trophic level. Animals of this trophic level are called secondary consumers because they are feeding on the herbivores who have already consumed energy from plants.
63. What is the fourth trophic level, and why are the organisms in this level called tertiary consumers?
Answer : The fourth trophic level is also made-up of carnivores. These animals feed on other carnivores. The energy is transferred from the third trophic level to the fourth trophic level. Animals of the fourth trophic level are called tertiary consumers.
64. Discuss the role of decomposers in the ecosystem. Why are they important in maintaining the energy cycle?
Answer : Decomposers include microorganisms like bacteria and fungi. They breakdown the dead and decaying matter into nutrients that can be used again. Decomposition of food, in fact, can take place at other trophic levels also. Thus, they are capable of receiving energy from all types of plants as well as animals. They also supply energy to all the organisms at all levels. Their main role includes acting as environmental cleaners by decaying dead plants and animals, aiding in the recycling of nutrients, and ensuring that plants get essential nutrients while preventing the piling up of dead matter and waste.
65. Explain the 10% energy transfer rule in trophic levels. How does it limit the length of food chains?
Answer : When energy is transferred from one level to another, only 10% is passed to the next higher trophic level. Remaining 90% is released to the environment. The primary producers, therefore, receive maximum energy and carnivores at the fourth level receive minimum energy. There is a continuous decline in the energy as it transfers from one trophic level to another throughout the food chain. It means that longer the food chain, lesser the amount of energy available to the last recipient. This way the food chain cannot be more than five or six levels. Herbivores, therefore, get more energy than the carnivores.
66. What is the importance of energy flow in an ecosystem? Discuss at least five reasons.
Answer : Energy flow is the phenomenon that is responsible to sustain life on this planet. All the biotic components in this ecosystem need energy for their survival. If the energy flow in an ecosystem is disturbed, then it leads to ecological imbalance. It is vital for all living things in the ecosystem to survive and function properly. It helps us to understand who eats whom in nature. More the diversity of organisms, more stable the ecosystem is. It shows how all creatures in an ecosystem depend on each other and how changes can affect each other. It helps us to see how human actions are affecting the ecosystem. Understanding the flow of energy in an ecosystem helps us to devise proper conservation techniques to save the ecosystem.
67. Define a food chain. What are the major components of a food chain?
Answer : A food chain explains which organism eats another organism in the environment. It is a linear sequence of organisms where nutrients and energy is transferred from one organism to the other. It begins with the producer organism, follows the chain, and ends with the decomposer organism. The food chain consists of four major parts, namely: The Sun, which is the initial source of energy providing energy for everything on the planet; Producers, which include all autotrophs such as phytoplankton, cyanobacteria, algae, and green plants; Consumers, which contain almost all living organisms i.e., herbivores, carnivores, parasites, and lastly the scavengers; and Decomposers, which act as environmental cleaners by decaying dead plants and animals and aid in the recycling of nutrients.
Additional MCQs
1. What is the ultimate source of energy for all living organisms?
A. Soil
B. Water
C. Sunlight
D. Air
Answer: C. Sunlight
Q. What does the term “energy flow” refer to in an ecosystem?
A. Transfer of nutrients
B. Transfer of energy through food
C. Water cycle
D. Mineral cycling
Answer: B. Transfer of energy through food
Q. Which law governs the flow of energy in ecosystems?
A. Law of Gravity
B. Laws of Thermodynamics
C. Law of Motion
D. Law of Ecology
Answer: B. Laws of Thermodynamics
Q. In the first trophic level, what process converts sunlight into chemical energy?
A. Respiration
B. Photosynthesis
C. Decomposition
D. Fermentation
Answer: B. Photosynthesis
Q. What is the most important by-product of photosynthesis?
A. Glucose
B. Oxygen
C. Carbon dioxide
D. Water
Answer: B. Oxygen
Q. Which organisms are known as primary producers in an ecosystem?
A. Animals
B. Decomposers
C. Plants
D. Herbivores
Answer: C. Plants
Q. What type of consumers feed on plants?
A. Carnivores
B. Herbivores
C. Omnivores
D. Decomposers
Answer: B. Herbivores
Q. Herbivores are also referred to as?
A. Primary consumers
B. Secondary consumers
C. Tertiary consumers
D. Quaternary consumers
Answer: A. Primary consumers
Q. What characterizes the third trophic level in an ecosystem?
A. Plants producing food
B. Herbivores feeding on plants
C. Carnivores feeding on herbivores
D. Decomposers recycling nutrients
Answer: C. Carnivores feeding on herbivores
Q. Animals that feed on other carnivores are known as?
A. Primary consumers
B. Secondary consumers
C. Tertiary consumers
D. Producers
Answer: C. Tertiary consumers
Q. Which trophic level includes microorganisms like bacteria and fungi that decompose dead matter?
A. First
B. Third
C. Fourth
D. Fifth
Answer: D. Fifth
Q. Approximately what percentage of energy is transferred from one trophic level to the next?
A. 10%
B. 25%
C. 50%
D. 90%
Answer: A. 10%
Q. A longer food chain results in what outcome regarding energy availability?
A. Increased energy at higher levels
B. Constant energy through levels
C. Reduced energy at the top
D. No energy loss
Answer: C. Reduced energy at the top
Q. Why is energy flow essential in an ecosystem?
A. It recycles water
B. It sustains life
C. It eliminates waste
D. It creates habitats
Answer: B. It sustains life
Q. What does a food chain represent?
A. A network of water sources
B. A cycle of nutrients
C. A linear sequence of organisms
D. A habitat map
Answer: C. A linear sequence of organisms
Q. Which component is typically the final link in a food chain?
A. Producer
B. Consumer
C. Decomposer
D. Herbivore
Answer: C. Decomposer
Q. What is the main role of decomposers in an ecosystem?
A. Pollination
B. Nutrient recycling
C. Energy storage
D. Primary production
Answer: B. Nutrient recycling
Q. How is a food web best described?
A. A single linear food chain
B. A complex network of interconnected food chains
C. A diagram of water cycles
D. A seasonal feeding pattern
Answer: B. A complex network of interconnected food chains
Q. What advantage does a food web have over a food chain?
A. Simplicity
B. Clear linear paths
C. Representation of complex interactions
D. Exclusion of decomposers
Answer: C. Representation of complex interactions
Q. What is the main source of atmospheric oxygen?
A. Respiration
B. Photosynthesis
C. Combustion
D. Decomposition
Answer: B. Photosynthesis
Q. In the carbon cycle, carbon dioxide is fixed by plants during which process?
A. Respiration
B. Combustion
C. Photosynthesis
D. Decomposition
Answer: C. Photosynthesis
Q. Which process is responsible for releasing carbon back into the atmosphere?
A. Photosynthesis
B. Respiration
C. Evaporation
D. Condensation
Answer: B. Respiration
Q. Which type of bacteria converts atmospheric nitrogen into ammonia?
A. Nitrifying bacteria
B. Denitrifying bacteria
C. Nitrogen-fixing bacteria
D. Decomposers
Answer: C. Nitrogen-fixing bacteria
Q. What is the role of nitrifying bacteria in the nitrogen cycle?
A. Convert ammonia to nitrate
B. Fix atmospheric nitrogen
C. Convert nitrate to nitrogen
D. Decompose organic matter
Answer: A. Convert ammonia to nitrate
Q. Lightning in the nitrogen cycle converts atmospheric nitrogen directly into which compound?
A. Ammonia
B. Nitrate
C. Nitrite
D. Nitrous oxide
Answer: B. Nitrate
Q. What function do denitrifying bacteria serve in the nitrogen cycle?
A. Fix nitrogen
B. Convert nitrates to nitrogen
C. Convert ammonia to nitrate
D. Decompose proteins
Answer: B. Convert nitrates to nitrogen
Q. In the hydrological cycle, which process involves water vapor turning into liquid water?
A. Evaporation
B. Transpiration
C. Condensation
D. Infiltration
Answer: C. Condensation
Q. Ecological balance refers to the equilibrium between which components?
A. Energy and matter
B. Producers and consumers
C. Biotic and abiotic
D. Land and water
Answer: C. Biotic and abiotic
Q. Which of the following is a man-made factor that can disturb ecological balance?
A. Deforestation
B. Natural disasters
C. Volcanic eruptions
D. Earthquakes
Answer: A. Deforestation
Q. Preserving ecological balance primarily involves?
A. Increasing pollution
B. Habitat destruction
C. Restoring natural interactions
D. Reducing species diversity
Answer: C. Restoring natural interactions
Q. How is “energy flow” defined in ecological terms?
A. Movement of water
B. Transfer of energy in an ecosystem
C. Recycling of nutrients
D. Decomposition process
Answer: B. Transfer of energy in an ecosystem
Q. A food chain is defined as a chain in which what is transferred?
A. Water
B. Nutrients
C. Energy
D. Matter
Answer: C. Energy
Q. A food web is formed when many food chains are what?
A. Repeated
B. Isolated
C. Interconnected
D. Simplified
Answer: C. Interconnected
Q. Which adaptation helps protect polar bears from the cold?
A. Thick blubber
B. Long hair between pads
C. Large ears
D. Short tail
Answer: B. Long hair between pads
Q. Polar bears primarily feed on which of the following?
A. Berries
B. Seals
C. Fish
D. Insects
Answer: B. Seals
Q. What is the average weight of most male polar bears?
A. 350 kg
B. 800 kg
C. 150 kg
D. 500 kg
Answer: A. 350 kg
Q. Which sense is notably strong in polar bears, aiding in their hunting?
A. Sight
B. Smell
C. Hearing
D. Taste
Answer: B. Smell
38. What aspect of a food web makes an ecosystem more sustainable?
A. Linear energy flow
B. Complex interactions
C. Limited connections
D. Fixed trophic levels
Answer: B. Complex interactions
