Practice Questions for Science Class 10th "Our Environment"

e Choice Questions (MCQs):

1. D) Manufacturers - An ecosystem includes producers, consumers, and decomposers, not manufacturers.
2. A) Sun - The sun is the primary source of energy for nearly all ecosystems.
3. B) The position of an organism in the food chain - Trophic levels represent the feeding positions in a food chain.
4. C) Bacteria - Bacteria are biotic (living) components, whereas water, temperature, and light are abiotic.
5. A) Greenhouse effect - This process traps heat within the atmosphere, causing a warming effect.
6. C) Chlorofluorocarbons (CFCs) - CFCs have been major contributors to ozone layer depletion.
7. C) To break down dead organic matter - Decomposers recycle nutrients by decomposing dead material.
8. A) Primary consumers - Herbivores feed directly on plants, hence they are primary consumers.
9. A) Always upright - Energy pyramids are always upright because energy decreases as it moves up the food chain.
10. A) Biomass - Biomass refers to the total mass of living organisms in a trophic level.
11. B) Photosynthesis - Photosynthesis is a natural process beneficial to the environment, not a cause of degradation.
12. B) Increase in the concentration of a substance as it moves up the food chain - Biological magnification leads to higher concentrations of toxins at higher trophic levels.
13. C) Algae - Algae are primary producers, hence at the first trophic level in aquatic ecosystems.
14. B) Climax - A climax community represents a mature, stable ecosystem.
15. C) Increased photosynthesis - While initially, warming might increase photosynthesis, extreme warming can have negative effects.
16. A) Can be broken down by bacteria and other organisms - Biodegradable materials decompose naturally.
17. C) To produce organic compounds from inorganic substances - Autotrophs, or producers, convert inorganic materials into organic compounds through photosynthesis.
18. C) Fossil fuels - Fossil fuels are non-renewable as they take millions of years to form.
19. C) Ecosystem imbalance - Loss of biodiversity often leads to instability in ecosystems.
20. B) Recycling - Recycling involves converting waste into new materials and objects.

Short Answer Questions:

21. Ecosystem Definition: A community of living and non-living things interacting with each other in a specific environment.
22. Food Chain vs. Food Web:

• Food Chain: A linear sequence of organisms where each is food for the next.
• Food Web: A complex network of many interconnected food chains, showing the interdependence in an ecosystem.

23. Significance of Ozone Layer: It absorbs most of the sun's ultraviolet radiation, protecting life from harmful UV rays.
24. Greenhouse Effect and Global Warming: Greenhouse gases trap heat, leading to an increase in Earth's temperature, causing climate change.
25. Biological Magnification:

• Example: DDT in aquatic ecosystems increases in concentration as it moves from plankton to fish to larger predators.

26. Roles in Ecosystem:

• Producers: Convert solar energy into chemical energy (e.g., plants).
• Consumers: Feed on producers or other consumers.
• Decomposers: Break down dead matter into nutrients.

27. Deforestation Impact: Leads to loss of habitat, increased CO₂ levels, soil erosion, and disruption of water cycles.
28. Biodegradable vs. Non-Biodegradable:

• Biodegradable: Decomposes naturally, e.g., paper.
• Non-Biodegradable: Does not break down easily, e.g., plastics.

29. Pyramid of Numbers: Shows the number of organisms at each trophic level, usually decreasing as you move up.
30. Biodiversity Importance: Ensures ecosystem stability, resilience, and provides resources like food, medicine, and ecosystem services.
31. Sources of Air Pollution: Vehicle emissions, industrial processes, burning of fossil fuels, and agricultural practices.
32. Eutrophication Effects: Excessive nutrients lead to algal blooms, oxygen depletion, and death of aquatic life.
33. Sustainable Development: Meeting the needs of the present without compromising future generations' ability to meet their own needs.
34. Waste Management for Sustainability: Composting organic waste to return nutrients to the soil.
35. Human Impact on Carbon Cycle: Burning fossil fuels and deforestation increase atmospheric CO₂, altering the cycle.
36. Nitrogen Cycle Role: Converts nitrogen gas into forms usable by plants, crucial for protein synthesis and growth.
37. Recycling Plastics: Difficult due to different types, contamination, degradation over time, and energy-intensive processes.
38. Acid Rain Effects: Damages forests, aquatic ecosystems, buildings, and can affect soil fertility and human health.
39. Renewable Energy and Environment: Reduces greenhouse gas emissions, decreases reliance on finite resources.
40. Carrying Capacity: The maximum population size an environment can sustain indefinitely without degrading the resource base.

Long Answer Questions:

41. Energy Flow in Ecosystems:

• Energy enters through photosynthesis by producers, moves through consumers, and decreases at each trophic level due to inefficiencies like respiration. Energy pyramids illustrate this loss.

42. Human Impact - Deforestation:

• Leads to habitat loss, species extinction, increased carbon dioxide, climate change, and soil erosion, disrupting ecosystem balance.

43. Carbon Cycle:

• Involves photosynthesis, respiration, decomposition, and combustion. Human activities like burning fossil fuels add extra CO₂, enhancing the greenhouse effect.

44. Types of Ecosystems:

• Terrestrial: Forests, deserts, grasslands, with varying biodiversity and productivity.
• Aquatic: Oceans, lakes, rivers, each with unique species and productivity levels based on nutrient availability.

45. Pollutants in Aquatic Ecosystems:

• Chemical: Industrial effluents, pesticides; Thermal: From power plants altering water temperature; Biological: Introduction of invasive species.

46. Food Web and Stability:

• By linking multiple food chains, food webs provide alternative pathways for energy and nutrient flow, enhancing ecosystem resilience.

47. Reducing Biological Magnification:

• Minimize use of persistent pollutants, regulate industrial emissions, promote organic farming, and educate about chemical disposal.

48. Biodiversity Conservation:

• Strategies include habitat protection, species reintroduction, laws against poaching, and promoting sustainable practices.

49. Ecosystem Interconnectedness:

• Example: Removal of top predators can cause overpopulation of herbivores, leading to vegetation loss and soil degradation.

50. Ecological Pyramids:

• Numbers: Number of organisms; Biomass: Mass of organisms; Energy: Energy content, all generally decrease at higher trophic levels.

51. Microorganisms in Ecosystem Balance:

• Decompose organic matter, fix nitrogen, aid in nutrient cycling, and control pathogen populations.

52. Sustainable Agriculture:

• Crop rotation, organic farming, permaculture, reducing chemical inputs, and enhancing biodiversity to maintain soil health.

53. Plastic Pollution on Marine Life:

• Leads to ingestion by marine animals, entanglement, habitat destruction, and introduction of microplastics into the food chain.

54. Evolution of Waste Management:

• From simple dumping to integrated systems involving recycling, composting, waste-to-energy, and zero-waste initiatives.

55. Climate Change Impacts:

• Alters species distribution, timing of natural events, increases frequency of extreme weather, and can lead to loss of habitats like coral reefs.

56. Biomagnification and Pesticides:

• Pesticides accumulate in the food chain, affecting higher trophic levels more severely, as seen with DDT and bird populations.

57. Keystone Species:

• Their removal (e.g., wolves from Yellowstone) can lead to a cascade of ecological changes, altering the entire ecosystem's structure.

58. Global Initiatives on Greenhouse Gases:

• Kyoto Protocol aimed at reducing emissions with mixed success; Paris Agreement focuses on global cooperation, with ongoing assessments of effectiveness.

59. Interdependence in Ecosystems:

• Example: Pollinators like bees are crucial for plant reproduction, which in turn supports herbivores and the entire food chain.

60. Education and Environmental Conservation:

• Awareness campaigns, school curricula integrating environmental science, community involvement in conservation projects, and promoting sustainable practices.

Application-Based Questions:

61. Decomposition Experiment:

• Bury different materials in soil, observe over time which decompose, indicating activity of decomposers.

62. Explaining Ecosystem to Kids:

• Use an analogy like a "nature classroom" where plants are teachers, animals are students, and the environment is the classroom, all interacting.

63. Pond Ecosystem Food Web:

• Include algae (producer), tadpoles/small fish (primary consumers), frogs/fish (secondary consumers), birds/snakes (tertiary consumers), and bacteria/fungi (decomposers).

64. Acid Rain Demonstration:

• Grow two sets of plants; water one with slightly acidic water to mimic acid rain, compare growth and health.

65. Measuring Biodiversity:

• Count different species in a plot, use indices like species richness or Simpson's Diversity Index.

66. Simulating Carbon Cycle:

• Use balls to represent carbon atoms, moving them between "plants," "animals," "decomposers," "atmosphere," and "oceans" to show carbon movement.

67. School Waste Management Plan:

• Segregate waste at source, compost organic waste, set up recycling stations, reduce single-use plastics, and educate on waste reduction.

68. Biological Magnification Model:

• Use different sizes of containers to represent trophic levels, add colored dye (simulating pollutant) in increasing concentration.

69. Educational Campaign for Sustainable Living:

• Focus: Energy conservation, waste reduction, water saving, and promoting local, organic foods.
• Methods: Posters, workshops, social media challenges, and setting up a sustainability club.

70. Greenhouse Effect Model:

• Use a glass jar with a thermometer inside, compare temperature changes with and without the lid to show heat trapping.

Critical Thinking Questions:

71. Biodiversity Loss Impact:

• Economically, it can lead to loss of resources like medicines, food, and ecosystem services; socially, it affects cultural and recreational values, potentially leading to economic instability in sectors like tourism or agriculture.

72. Ethical Implications of Genetic Modification:

• Concerns include altering natural evolution, potential biodiversity loss, unknown long-term effects on ecosystems, and ethical questions about playing "God" with nature. Benefits might include disease resistance, increased food production, but these must be weighed against risks.

73. Balancing Development and Conservation:

• Through sustainable practices like green technology, eco-tourism, conservation agriculture, and policies that incentivize environmentally friendly businesses. Public-private partnerships can also fund conservation while supporting economic growth.

74. Challenges in Global Environmental Policies:

• Differences in national interests, economic disparities, enforcement difficulties, political will, and the need for equitable burden sharing. Additionally, the complexity of global issues like climate change requires international cooperation which can be slow and contentious.

75. Technology in Mitigating Climate Change:

• Renewable energy technologies, carbon capture and storage, smart agriculture, geoengineering solutions like solar radiation management, and digital tools for monitoring environmental health and educating the public.

76. Ecological Debt:

• Refers to the idea that developed nations have historically used more than their fair share of the planet's resources, leaving a "debt" to developing countries. It's relevant in discussions about responsibility for climate change mitigation and resource use equity.

77. Invasive Species Impact:

• They can outcompete native species, alter habitats, introduce diseases, and disrupt food webs. Control strategies include biological control, mechanical removal, chemical treatments, and prevention of new introductions through regulations.

78. Effectiveness of Climate Treaties:

• Kyoto Protocol: Had mixed results; some countries met targets, but major emitters like the US did not participate, reducing its impact.
• Paris Agreement: More inclusive but still faces challenges in accountability and enforcement. Its effectiveness is being evaluated through global stocktakes.

79. Adapting Education for Environmental Stewardship:

• Integrate environmental education into all subjects, use experiential learning like field trips, promote project-based learning on sustainability, and encourage critical thinking about environmental issues and solutions.

80. Consequences of Continued Deforestation and Pollution:

• Deforestation: Loss of biodiversity, climate change acceleration, increased natural disasters, and reduced carbon sequestration capacity.
• Pollution: Health problems, water and air quality degradation, loss of ecosystems, and exacerbation of climate change effects, potentially leading to uninhabitable conditions in some areas.