Environment and Ecosystem

Overview

Environment and Ecosystem is a foundational topic in the Science section of JTET Paper II, bridging biology with environmental awareness. This topic tests your understanding of how living organisms interact with each other and their physical surroundings—a concept central to both scientific literacy and environmental education.

For JTET, expect questions on ecosystem components, energy flow through food chains and food webs, and the causes and effects of various types of pollution. Since Jharkhand is rich in forests and mineral resources but also faces environmental challenges from mining and industrialization, questions often connect ecological concepts to local contexts. Mastering this topic requires understanding both the theoretical framework of ecosystems and practical issues of environmental degradation.

Students must be able to identify producers, consumers, and decomposers, trace energy flow, distinguish between different pollution types, and suggest conservation measures—all at the upper-primary conceptual level.

Key Concepts

• **Ecosystem** is a functional unit of nature where living organisms (biotic components) interact with non-living factors (abiotic components) through energy flow and nutrient cycling.

• **Biotic components** include producers (green plants), consumers (herbivores, carnivores, omnivores), and decomposers (bacteria, fungi). **Abiotic components** include sunlight, water, soil, temperature, and air.

• **Food chain** represents a linear sequence of organisms where each serves as food for the next level. Energy flows in one direction—from producers to top consumers.

• **Food web** is an interconnected network of multiple food chains in an ecosystem, showing the complex feeding relationships among organisms.

• **Trophic levels** are feeding positions in a food chain: T1 (producers), T2 (primary consumers/herbivores), T3 (secondary consumers), T4 (tertiary consumers).

• **10% Law** (Lindeman's Law): Only about 10% of energy is transferred from one trophic level to the next; the rest is lost as heat through respiration.

• **Pollution** is the introduction of harmful substances (pollutants) into the environment, causing adverse changes. Major types: air, water, soil, and noise pollution.

• **Biodegradable pollutants** (sewage, paper) can be broken down by microorganisms; **non-biodegradable pollutants** (plastics, heavy metals) persist in the environment.

Formulas / Key Facts

| Concept | Key Fact | |---------|----------| | Energy transfer | Only 10% energy passes to next trophic level | | Pyramid of energy | Always upright; energy decreases at higher levels | | Pyramid of numbers | Can be upright (grassland) or inverted (tree ecosystem) | | Ozone layer | Found in stratosphere; absorbs UV radiation | | Greenhouse gases | CO₂, CH₄, N₂O, CFCs trap heat, causing global warming | | BOD (Biochemical Oxygen Demand) | High BOD indicates polluted water | | Eutrophication | Excess nutrients cause algal bloom, depleting oxygen | | pH of acid rain | Below 5.6 (normal rain is about 5.6) | | Safe noise level | Below 85 decibels for prolonged exposure | | Major air pollutants | CO, SO₂, NO₂, particulate matter, lead |