Environment and Ecology

Overview

Environment and Ecology is a high-scoring topic in GTET Paper-2 Science section that connects biological concepts with real-world environmental issues. This topic tests your understanding of how living organisms interact with each other and their physical surroundings, forming complex systems that sustain life on Earth.

For GTET, you must understand ecosystem structure and function, levels of biodiversity, types and effects of pollution, and conservation strategies. Questions often link theoretical concepts to practical examples—particularly those relevant to Gujarat's unique ecosystems like the Gir forest, Rann of Kutch, and Gulf of Khambhat. Expect 3-5 questions directly from this topic, with additional questions integrating ecology into pedagogy scenarios.

Mastery requires understanding ecological relationships, memorising key terms and examples, and applying conservation principles to classroom teaching contexts.

Key Concepts

• **Ecosystem** is a functional unit comprising living organisms (biotic) and non-living environment (abiotic) interacting through energy flow and nutrient cycling. Examples: pond, forest, desert.

• **Food chain** shows linear transfer of energy from producers → primary consumers → secondary consumers → tertiary consumers. Only 10% energy transfers to the next level (10% Law by Lindeman).

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

• **Biodiversity** refers to variety of life at three levels: genetic diversity (within species), species diversity (between species), and ecosystem diversity (variety of habitats).

• **Biogeochemical cycles** are pathways through which nutrients like carbon, nitrogen, and water circulate between biotic and abiotic components.

• **Ecological succession** is the gradual replacement of one community by another until a stable climax community is reached. Primary succession starts on bare rock; secondary succession occurs after disturbance.

• **Pollution** is the introduction of harmful substances into the environment causing adverse changes. Classified as air, water, soil, and noise pollution.

• **Conservation** includes all measures to protect, preserve, and sustainably manage natural resources and biodiversity for present and future generations.

Formulas / Key Facts

| Concept | Key Fact | |---------|----------| | Energy flow | Unidirectional; only 10% energy passes to next trophic level | | Biomass pyramid | Always upright in terrestrial ecosystems; inverted in aquatic (pond) ecosystems | | Number pyramid | Inverted in parasitic food chain and tree ecosystem | | Biodiversity hotspots | India has 4 hotspots: Western Ghats, Himalayas, Indo-Burma, Sundaland | | Endemic species | Species found only in one geographical area (e.g., Asiatic Lion in Gir) | | Ozone layer | Found in stratosphere (15-35 km); depleted by CFCs | | Greenhouse gases | CO₂, CH₄, N₂O, CFCs cause global warming | | BOD | Biological Oxygen Demand—higher BOD indicates more polluted water | | Protected areas in Gujarat | Gir National Park, Marine National Park (Gulf of Kutch), Wild Ass Sanctuary (Little Rann) | | Ramsar sites in Gujarat | Nalsarovar Bird Sanctuary, Khijadiya Bird Sanctuary |