Our Environment Class 10

Our Environment explains how living organisms interact with one another and with the non-living components of their surroundings. Students study ecosystems, food chains, trophic levels, energy flow, decomposers, biological magnification, waste and the ozone layer.

The chapter connects Biology with environmental decision-making. It explains why removing one species can affect an entire food web, why energy limits the number of trophic levels and why certain pollutants become more dangerous at higher levels of a food chain.

Ecosystems and their components

An ecosystem includes a community of living organisms and the physical environment with which they interact. Its components are classified as:

• Biotic components: Plants, animals, microorganisms and other living organisms

• Abiotic components: Air, water, soil, light, temperature and minerals

Living organisms are also grouped according to their role:

• Producers prepare organic food, usually through photosynthesis.

• Consumers obtain food by eating plants or other animals.

• Decomposers break down dead organisms and waste, returning nutrients to the environment.

Food chains, food webs and trophic levels

A food chain represents the sequence through which food and energy pass from one organism to another. Each feeding position is called a trophic level. Green plants occupy the first trophic level, herbivores the second, and carnivores occupy higher levels.

Real ecosystems contain interconnected food chains called food webs. Food webs provide alternative feeding relationships and make ecosystems more complex than a single straight chain.

Flow of energy and the ten per cent law

Energy enters most ecosystems through sunlight. Producers capture a small part of solar energy and convert it into chemical energy. Only about ten per cent of the energy available at one trophic level is transferred to the next trophic level; most is used in life processes or lost as heat.

This one-way energy flow explains why:

• Food chains are usually short

• Organisms at higher trophic levels are fewer

• A pyramid of energy remains upright

• Energy is not recycled in the way matter is recycled

Biological magnification

Some non-biodegradable pollutants enter food chains and are not effectively broken down or removed. Their concentration can increase at successive trophic levels. This process is called biological magnification. Organisms at the highest trophic level may therefore accumulate the greatest concentration.

Waste and the ozone layer

Students compare biodegradable and non-biodegradable substances. Biodegradable waste can be broken down through biological processes, while non-biodegradable waste may persist and accumulate.

The ozone layer absorbs much of the Sun’s harmful ultraviolet radiation. Certain chemicals, particularly chlorofluorocarbons, contributed to ozone depletion. International action has helped restrict many ozone-depleting substances.

Learn Our Environment with Teachoo

Teachoo provides detailed Class 10 Our Environment notes, NCERT Solutions, food-chain questions and MCQs. Students learn to identify trophic levels, calculate energy transfer and explain environmental effects through cause-and-effect relationships.

The chapter includes:

• Concept-wise notes

• NCERT in-text and exercise solutions

• Questions from inside the chapter

• Teachoo Questions

• Case-based MCQs

• Assertion–reason questions

• Previous-year and NCERT Exemplar MCQs

• Past-year questions organised by marks

How should you prepare Our Environment?

Practise constructing valid food chains from organism lists. Mark each trophic level and trace both energy movement and pollutant concentration. Learn the role of decomposers separately from the transfer of energy between trophic levels.

Frequently Asked Questions

What is an ecosystem?

An ecosystem is a functional unit consisting of living organisms and the non-living environment interacting with one another.

What is the ten per cent law?

It states that only about ten per cent of the energy available at one trophic level is transferred to the next trophic level.

What is biological magnification?

Biological magnification is the increase in concentration of certain persistent pollutants at successive trophic levels of a food chain.

Why are decomposers important?

Decomposers break down dead organisms and organic waste, return nutrients to the environment and prevent dead matter from accumulating indefinitely.

Does Teachoo provide Our Environment MCQs and NCERT Solutions?

Yes. Teachoo provides NCERT Solutions, food-chain questions, case-based MCQs, assertion–reason questions, Exemplar MCQs and previous-year questions.