OUR ENVIRONMENT: Short Answer Type Questions for Class 10th Chapter 10 JKBOSE/NCERT

OUR ENVIRONMENT: Short Answer Type Questions for Class 10th Chapter 10 JKBOSE/NCERT


Question 1. Why are some substances biodegradable and some non-biodegradable?

Ans: The biodegradability of substances depends on their chemical composition and the ability of natural processes, such as microbial action, to break them down into simpler compounds. Biodegradable substances usually consist of organic matter, such as plant material or certain types of plastics derived from natural sources. These substances contain chemical bonds that can be broken down by microorganisms, enzymes, or natural degradation processes.

On the other hand, non-biodegradable substances typically consist of materials that have complex chemical structures or are synthetic. These substances are not easily broken down by natural processes within a reasonable timeframe. They may include materials like certain plastics, metals, glass, and synthetic chemicals. Non-biodegradable substances may have chemical bonds that are resistant to microbial or enzymatic degradation, leading to their persistence in the environment.

Question 2. Give any two ways in which biodegradable substances would affect the environment.

Ans: Two ways in which biodegradable substances can affect the environment are:

Nutrient Cycling: Biodegradable substances, when decomposed by microorganisms, contribute to the recycling of nutrients in ecosystems. This nutrient cycling helps maintain the fertility of the soil, promotes plant growth, and supports the overall health and functioning of ecosystems.

Soil Improvement: Biodegradable substances, such as organic waste or compost, can be used to improve soil quality. When added to the soil, these substances enhance its structure, water-holding capacity, and nutrient content. They promote the growth of beneficial microorganisms, improve soil fertility, and support sustainable agricultural practices.

Question 3. Give any two ways in which non-biodegradable substances would affect the environment.

Ans: Two ways in which non-biodegradable substances can affect the environment are:

Pollution and Accumulation: Non-biodegradable substances, especially plastics and synthetic chemicals, can accumulate in the environment over time. This accumulation leads to pollution of land, water bodies, and ecosystems. It disrupts natural habitats, harms wildlife, and poses risks to human health.

Ecological Disruption: Non-biodegradable substances can cause ecological imbalances and disruptions. For example, plastic debris in oceans can entangle marine animals, leading to injuries, suffocation, or death. Non-biodegradable substances can alter natural processes, harm biodiversity, and disrupt the delicate balance of ecosystems.

Question 4. What is a food web? Give an example.

Ans: A food web represents a more complex and interconnected network of feeding relationships within an ecosystem.

In a food web, organisms are grouped into different trophic levels based on their feeding relationships. It demonstrates the various pathways of energy flow and the complex interactions among producers, consumers, and decomposers within an ecosystem. Multiple food chains in a food web are connected through organisms that occupy more than one trophic level, acting as both predators and prey.

For example, in a forest ecosystem food web, the primary producers, such as trees and plants, provide energy and nutrients to herbivores, such as deer and rabbits. The herbivores, in turn, become food sources for secondary consumers like foxes and snakes. Additionally, decomposers, such as fungi and bacteria, break down dead organisms and organic matter, completing the cycle. The food web illustrates the intricate connections and flow of energy within the ecosystem, demonstrating the interdependence of various species.

Question 5. What will happen if we kill all the organisms at a trophic level?

Ans: If all the organisms at a trophic level were killed, it would have significant consequences for the functioning and stability of the ecosystem. Trophic levels represent the energy flow and interactions among different organisms, and each level plays a specific role.

Disruption of Energy Flow: Organisms in a trophic level serve as a source of energy for the next trophic level. If all organisms in a trophic level are eliminated, the energy transfer to higher trophic levels would be severely affected. This disruption can lead to energy shortages and imbalances in the ecosystem.

Impact on Predators and Prey: Removing all organisms at a trophic level would impact the predators that rely on them as a food source. It would disrupt the predator-prey dynamics and could lead to a decline or loss of certain predator species.

Cascading Effects: The removal of an entire trophic level can have cascading effects throughout the ecosystem. It can disrupt the balance of populations, alter species interactions, and potentially lead to ecological imbalances and changes in biodiversity.

Overall, the loss of organisms at a trophic level would disrupt the energy flow, affect predator-prey relationships, and have far-reaching consequences for the structure and functioning of the ecosystem.

Question 6. What will happen if decomposers are not there in the environment?

Ans: Decomposers play a crucial role in the environment by breaking down dead organic matter and recycling nutrients back into the ecosystem. If decomposers are not present, the consequences can be detrimental to the environment:

Nutrient Recycling: Decomposers, such as bacteria and fungi, break down dead plants, animals, and other organic material, releasing nutrients back into the soil or water. Without decomposers, the recycling of essential nutrients, such as carbon, nitrogen, and phosphorus, would be disrupted.

Organic Matter Accumulation: In the absence of decomposers, dead organic matter would accumulate and remain in the environment for longer periods. This accumulation can lead to the buildup of organic debris, reducing space for new growth and potentially creating habitats for pests or disease-causing organisms.

Ecosystem Imbalance: Decomposers help maintain the balance of an ecosystem by breaking down dead organisms and returning their components to the nutrient cycle. Without decomposers, there would be a disturbance in the natural processes that regulate population sizes, nutrient availability, and overall ecosystem functioning.

Question 8. What is ozone? How does it affect an ecosystem?

Ans: Ozone is a molecule composed of three oxygen atoms (O3). It is primarily found in the Earth’s stratosphere, forming the ozone layer. The ozone layer plays a crucial role in the environment and ecosystems:

Ultraviolet (UV) Radiation Protection: The ozone layer acts as a protective shield against harmful UV radiation from the Sun, particularly UV-B and UV-C rays. It absorbs a significant portion of these rays, preventing them from reaching the Earth’s surface. UV radiation can cause DNA damage, skin cancer, cataracts, reduced crop yields, and harm to marine ecosystems. The ozone layer helps mitigate these risks by reducing the amount of UV radiation that reaches the biosphere.

Climate Regulation: Ozone is also a greenhouse gas that contributes to regulating the Earth’s climate. It absorbs and emits thermal radiation, helping to balance the Earth’s temperature. Changes in the ozone layer can affect the vertical temperature structure of the atmosphere, influencing weather patterns and climate dynamics.

Question 9. Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

Ans: Damage to the ozone layer is a cause for concern due to several reasons:

Increased UV Radiation Exposure: Depletion of the ozone layer allows more UV radiation to reach the Earth’s surface. Prolonged exposure to UV radiation can lead to skin cancer, cataracts, weakened immune systems, and other health issues in humans and animals. It can also negatively impact phytoplankton, marine ecosystems, and agricultural productivity.

Disruption of Ecosystems: UV radiation can harm aquatic ecosystems by affecting the growth and development of phytoplankton, the base of the marine food chain.

Steps have been taken to limit ozone layer damage, primarily through international agreements and regulations:

Montreal Protocol: The Montreal Protocol, signed in 1987, is an international treaty aimed at phasing out the production and use of ozone-depleting substances (ODS). It has been successful in significantly reducing the production and consumption of substances such as chlorofluorocarbons (CFCs) and halons, which are known to deplete the ozone layer.

Substitution of ODS: The Montreal Protocol has prompted the development and use of alternative substances that have lower or no ozone depletion potential. For example, hydrochlorofluorocarbons (HCFCs) were introduced as transitional substitutes for CFCs, but they are being phased out as well due to their impact on climate change. Similarly, hydrofluorocarbons (HFCs) are being phased down as they have high global warming potential.

Monitoring and Research: Continuous monitoring of ozone levels and research on ozone depletion processes are crucial to assess the effectiveness of control measures and identify emerging concerns. International organizations, such as the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO), coordinate global efforts to monitor the ozone layer and provide scientific assessments and recommendations.

Question 10. If all the waste we generate is biodegradable, will this have no impact on the environment?

Ans: If all the waste we generate is biodegradable, it would have a significantly reduced impact on the environment compared to non-biodegradable waste. Biodegradable waste can be broken down naturally by microorganisms and natural processes, leading to the recycling of nutrients and minimal long-term environmental harm. However, it is important to note that even biodegradable waste can cause some environmental issues if not managed properly:

Resource Consumption: The generation of large volumes of biodegradable waste can still consume significant resources, such as water and energy, for their collection, transportation, and treatment. Efficient waste management practices are necessary to minimize resource usage and associated environmental impacts.

Pollution and Emissions: Improper disposal or inefficient treatment of biodegradable waste, such as through uncontrolled landfilling or inadequate composting, can lead to the release of greenhouse gases, such as methane, a potent contributor to climate change. Methane emissions from decomposing biodegradable waste in landfills can be mitigated through landfill gas capture and utilization systems.

Land and Water Contamination: Biodegradable waste, when not managed properly, can still contribute to land and water pollution. If biodegradable waste enters water bodies, it can lead to eutrophication, a process where excessive nutrients promote the growth of harmful algae, depleting oxygen levels and negatively impacting aquatic life.

While biodegradable waste is generally less harmful, adopting waste reduction strategies, recycling, and proper waste management practices, including composting and anaerobic digestion, can further minimize the environmental impact of waste generation and disposal.

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