This chapter explains the meaning of the environment and how living organisms and non-living components interact to maintain balance in nature. It introduces the concept of an ecosystem, its biotic and abiotic components, and explains how energy flows through food chains and food webs. The chapter also highlights serious environmental concerns such as biological magnification, ozone layer depletion, and waste management, helping students understand how human activities affect the environment and why sustainable practices are essential.
Key Points
The environment includes all living and non-living things around us.
An ecosystem is formed by the interaction of living organisms with their physical surroundings.
Ecosystems have biotic components (plants, animals, microorganisms) and abiotic components (air, water, soil, temperature).
Producers are green plants that make food using photosynthesis.
Consumers depend directly or indirectly on producers for food.
Decomposers break down dead organisms and recycle nutrients back to the soil.
A food chain shows who eats whom in an ecosystem.
Each step in a food chain is called a trophic level.
Energy transfer between trophic levels follows the 10% law.
Only about 10% of energy is passed to the next trophic level.
Due to energy loss, food chains are usually short.
A food web is a network of interconnected food chains.
Energy flow in an ecosystem is unidirectional.
Harmful chemicals like pesticides enter food chains and accumulate.
Biological magnification is the increase in concentration of harmful substances at higher trophic levels.
Humans are most affected as they occupy the top trophic level.
The ozone layer protects Earth from harmful ultraviolet (UV) radiation.
CFCs are responsible for ozone layer depletion.
Ozone depletion increases risks like skin cancer and ecological damage.
Waste can be biodegradable or non-biodegradable.
Non-biodegradable waste persists in the environment for long periods.
Improper waste disposal causes serious environmental pollution.
Reduce, Reuse, and Recycle help manage waste effectively.
👉 👉Nature works as a balanced system, and human actions strongly influence it. By understanding ecosystems, conserving resources, reducing waste, and protecting the ozone layer, we can live responsibly and ensure a healthy environment for future generations.