Chapter 13: Our Environment
Cosystems and Food Chains
An ecosystem includes all living (biotic) and non-living (abiotic) components in a given area, such as plants, animals, microorganisms, soil, water, and temperature. These components interact to form a balanced and self-sustaining system. Organisms are categorized as producers (like green plants), consumers (herbivores, carnivores, omnivores), and decomposers (bacteria and fungi). Food chains represent how energy flows from producers to various levels of consumers, and these chains often interconnect to form complex food webs. Energy transfer in food chains is inefficient—only about 10% is passed on at each trophic level, limiting most chains to 3–4 steps.
Human Impact on the Environment
Human activities affect the environment in many ways. The use of pesticides introduces harmful chemicals into food chains, which accumulate through a process called biological magnification. This results in the highest concentration of toxins in top consumers, including humans. The depletion of the ozone layer is another concern. Ozone protects Earth from harmful ultraviolet radiation, but chemicals like chlorofluorocarbons (CFCs) have caused its thinning. Global efforts have led to regulations that restrict the use of CFCs to reduce further damage.
Waste Generation and Management
Everyday activities generate large amounts of waste, much of which is non-biodegradable. Biodegradable waste can be broken down naturally, while non-biodegradable waste, like plastics, can persist for centuries and harm ecosystems. Increasing dependence on disposable items and poor waste segregation worsen the problem. Proper management includes reducing usage, recycling materials, and separating biodegradable from non-biodegradable waste. Community awareness and responsible behavior are essential to minimize environmental damage and maintain ecological balance.