Our Environment — Telangana (SSC) Class 10 Science Solutions (Free)

Ecosystem: community of organisms interacting with physical environment in specific area. - Biotic components: all living things (plants, animals, microorganisms, humans) - Abiotic components: non-living factors (sunlight, water, temperature, air, soil, minerals) - These components interact to create a functional system supporting life

Food chain: linear sequence of organisms showing energy transfer through feeding. - Example: Grass → Grasshopper → Frog → Snake → Eagle - Each organism feeds on previous one Food web: interconnected food chains showing multiple feeding relationships. - More realistic representation of ecosystem - Shows that organisms eat multiple food sources - When one organism declines, energy flow redistributes through alternate chains

Producers: - Plants that make own food through photosynthesis - Form base of all food chains Consumers: - Primary: herbivores eating plants (grasshopper, cow) - Secondary: carnivores eating herbivores (frog, eagle) - Tertiary: top predators (lion, hawk) Decomposers: - Bacteria and fungi break down dead organisms - Return nutrients to soil for reuse by plants

Energy flow in ecosystem: - Solar energy captured by plants through photosynthesis - Energy passed to consumers through food chains - Energy lost as heat at each level due to metabolism and movement 10% rule: - Only 10% of energy from one level transfers to next level - 90% lost as heat - Example: if plants have 1000 units, herbivores get 100, carnivores get 10 - This limits number of trophic levels in ecosystem (usually 3-4)

Biodegradable waste: - Decomposes naturally by microorganisms - Returns to soil as nutrients - Examples: food scraps, paper, wood, plant material, manure - Decomposes in weeks to months Non-biodegradable waste: - Cannot be decomposed by natural processes - Persists in environment for years/centuries - Examples: plastics, metals, glass, synthetic chemicals - Causes environmental pollution and harm to organisms

Nitrogen cycle: movement of nitrogen through atmosphere, soil, water, and organisms. - Atmospheric nitrogen (N2) fixed by bacteria in soil and legume roots into usable form (NO3-) - Plants absorb nitrates for protein synthesis - Animals consume plants, nitrogen incorporated into body proteins - Dead organisms and waste decomposed by bacteria - Denitrifying bacteria release N2 back to atmosphere - Cycle ensures nitrogen availability for life processes

Ozone layer: - Located in stratosphere (15-35 km above Earth) - Contains ozone (O3) gas in high concentration Importance: - Absorbs ultraviolet (UV) radiation from sun - Prevents harmful UV from reaching Earth's surface Threat: - Chlorofluorocarbons (CFCs) from refrigerators and aerosols release chlorine atoms - Chlorine destroys ozone molecules - Ozone depletion causes increased UV radiation - Results in skin cancer, cataracts, immune suppression, crop damage Protection: Montreal Protocol banned CFCs to allow ozone recovery