Chapter 13 Our Environmnet KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS

Chapter 13 Our Environmnet KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS

 

Chapter 13 Our Environmnet KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS English medium Karnataka state board,the Answers Are Prepared By Our Teachers Which Are Simple ,Pointwise,Easy To Read And Remember .

 

Chapter 13 Our Environmnet KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS

1. What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

– Trophic levels: Steps in a food chain where organisms obtain their energy.

– Example of a food chain: Grass → Grasshopper → Frog → Snake → Eagle

Different trophic levels:

• First trophic level: Producers (e.g., Grass)
• Second trophic level: Primary consumers (e.g., Grasshopper)
• Third trophic level: Secondary consumers (e.g., Frog)
• Fourth trophic level: Tertiary consumers (e.g., Snake)
• Fifth trophic level: Quaternary consumers (e.g., Eagle)

 

2. What is the role of decomposers in the ecosystem?

– Role of decomposers:

• Break down dead organisms and waste products.
• Convert complex organic substances into simple inorganic substances.
• Recycle nutrients back into the soil.
• Enable plants to use these nutrients for growth.
• Prevent accumulation of dead matter and waste in the ecosystem.

 

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

• Biodegradable Substances:

– Broken down by microorganisms (bacteria, fungi).

– Natural materials like food waste, paper, and wood.

– Enzymes in microorganisms help decompose these materials.

 

• Non-Biodegradable Substances:

– Cannot be broken down by microorganisms.

– Synthetic materials like plastics and metals.

– Resistant to natural processes of decomposition.

 

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

• Nutrient Recycling:

– Decomposition of biodegradable substances releases nutrients back into the soil.

– These nutrients are used by plants for growth.

 

• Waste Reduction:

– Decomposed substances reduce the amount of waste in the environment.

– Helps maintain ecological balance.

 

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

• Pollution:

– Non-biodegradable substances like plastics cause long-term pollution.

– They accumulate in landfills and oceans, harming wildlife.

 

• Toxicity:

– Some non-biodegradable materials release harmful chemicals.

– These chemicals can contaminate soil and water, affecting health and ecosystems.

 

1. What is ozone and how does it affect any ecosystem?

– Ozone (O3):

– A molecule with three oxygen atoms.

– Exists high in the atmosphere.

 

– Effects on Ecosystem:

– Protection:

– Shields Earth from harmful ultraviolet (UV) radiation.

– Prevents skin cancer and other UV-related damage in living organisms.

– Depletion:

– Caused by chemicals like chlorofluorocarbons (CFCs).

– Leads to increased UV radiation reaching Earth’s surface.

– Results in health issues and environmental damage.

 

2. How can you help in reducing the problem of waste disposal? Give any two methods

 

– Method 1: Reduce and Reuse:

– Reduce:

– Buy products with minimal packaging.

– Avoid single-use items.

– Reuse:

– Use reusable bags, containers, and bottles.

– Repair items instead of throwing them away.

 

– Method 2: Recycle Properly:

– Separate Waste:

– Sort waste into recyclable and non-recyclable.

– Follow local recycling guidelines.

  – Compost Organic Waste:

– Compost kitchen scraps and garden waste.

– Reduces landfill waste and produces natural fertilizer.

EXERCISES

1. Which of the following groups contain only biodegradable items?

– (c) Fruit-peels, cake and lime-juice

 

2. Which of the following constitute a food-chain?

– (d) Grass, fish and goat

 

3. Which of the following are environment-friendly practices?

– (d) All of the above

– Carrying cloth-bags while shopping

– Switching off unnecessary lights and fans

– Walking to school instead of using motorized transport

 

4. What will happen if we kill all the organisms in one trophic level?

– It would disrupt the food chain, affecting organisms at higher trophic levels and altering the ecosystem balance.

 

5. Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?

– Removing organisms from any trophic level can disrupt the ecosystem, but the impact varies. Higher trophic levels may experience more severe consequences due to their dependence on lower levels.

 

6. What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?

– Biological magnification is the increasing concentration of harmful substances at higher trophic levels. The levels of magnification can vary depending on the persistence and toxicity of the substance.

 

7. What are the problems caused by the non-biodegradable wastes that we generate?

– Non-biodegradable wastes persist in the environment, causing physical and chemical pollution, harming wildlife, and contaminating soil and water resources.

 

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

– Biodegradable waste still affects the environment if not managed properly, such as contributing to methane emissions in landfills or contaminating water bodies if not treated.

 

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

– Damage to the ozone layer allows harmful UV radiation to reach the Earth’s surface, causing health issues like skin cancer and disrupting ecosystems. Steps include banning ozone-depleting substances like CFCs and promoting alternatives in industries and products worldwide.