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Chapter Overview
This chapter explains the environment as an interaction
between living and non-living components. It covers
ecosystem organisation, food chains, trophic levels,
energy flow, decomposition, biodegradable and
non-biodegradable substances, biological magnification
and the ozone layer.
The chapter also explains how human activities affect
ecosystems and why responsible waste management and
environmental protection are important.
📘 Complete Notes
Detailed notes on ecosystem, food chain, trophic levels,
energy flow, decomposition, waste and environmental issues.
❓ Important Questions
Conceptual, reasoning, comparison, case-based and
competency-focused questions.
📝 Previous Year Questions
Chapter-focused previous year questions and
examination practice.
🔢 Numericals
Energy-flow, trophic-level, 10% law and
ecological calculation practice.
Topics Covered
Environment
Ecosystem
Biotic Components
Abiotic Components
Producers
Consumers
Decomposers
Food Chain
Food Web
Trophic Levels
Energy Flow in Ecosystem
10 Percent Law
Ecological Pyramids
Decomposition
Biodegradable Substances
Non-Biodegradable Substances
Waste Management
Biological Magnification
Ozone Layer
Ozone Depletion
Environmental Pollution
Sustainable Environmental Practices
Quick Revision
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An ecosystem consists of living organisms and their physical environment.
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Producers prepare food and form the first trophic level.
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Consumers depend directly or indirectly on other organisms for food.
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Decomposers break down dead organic matter and recycle nutrients.
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Energy flows through an ecosystem from producers to consumers.
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Only a small fraction of energy is transferred from one trophic
level to the next.
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According to the 10% law, about 10% of energy is transferred
to the next trophic level.
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Biodegradable substances can be broken down by biological processes.
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Non-biodegradable substances persist for long periods and may
accumulate in the environment.
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Biological magnification refers to increasing concentration of
certain persistent pollutants at higher trophic levels.
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The ozone layer absorbs a large fraction of harmful ultraviolet radiation.
Food Chain and Trophic Levels
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Trophic Level
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Typical Organisms
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First
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Producers
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Second
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Primary Consumers / Herbivores
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Third
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Secondary Consumers
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Fourth
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Higher-level Consumers
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Important:
Energy available decreases sharply at successive
trophic levels.
Biodegradable and Non-Biodegradable
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Feature
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Biodegradable
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Non-Biodegradable
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Breakdown
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Can be broken down by biological processes
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Not easily broken down by natural biological processes
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Examples
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Food waste, paper, many natural organic wastes
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Many plastics, some synthetic chemicals
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Environmental Persistence
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Generally shorter
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Can persist for long periods
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