OUR ENVIRONMENT (NCERT) GRADE 10, Study notes of Biology

Download OUR ENVIRONMENT (NCERT) GRADE 10 and more Study notes Biology in PDF only on Docsity!

CHAPTER – OUR ENVIRONMENT

1. Environment

● The environment is the sum total of all external factors (living and non-living) that surround and influence an organism.

2. Ecosystem (Ecological System)

● A geographical area where living organisms (biotic) and non-living things (abiotic) interact and exchange materials and energy.

● Biotic Components: Plants, animals, fungi, bacteria

● Abiotic Components: Air, water, wind, soil, temperature, rainfall, pH

3. Types of Ecosystems

Natural Ecosystem Artificial

Ecosystem

● Maintained by nature ● Maintained by humans

○ Omnivores: Eat both plants and animals (e.g., humans, dogs)

○ Parasites: Live on/in a host and obtain food (e.g., lice, cuscuta)

● Decomposers: Break down dead organisms (e.g., bacteria,

fungi)

5. Functioning of Ecosystem

1. Producers convert solar energy to chemical energy (sugar, starch).
2. Consumers obtain energy by feeding on producers/other consumers.
3. Decomposers break down dead matter into nutrients (CO₂, water, minerals) which go back to the soil.

6. Food Web vs Food Chain

FOOD CHAIN FOOD WEB

● A linear sequence showing who eats whom.

● Network of interlinked food chains.

Simple and linear Multiple organisms per level Organisms at high trophic level feed upon a single type of organism.

Organisms at high trophic level feed upon a multiple type of organism. Easily disturbed by removal of one organism.

Less affected by species removal of one group.

○ Example (Forest): Trees → Deer → Lion

○ Example (Grassland): Grass → Grasshopper → Frog → Snake → Eagle

○ Example (Pond): Phytoplankton → Zooplankton → Small fish → Large fish → Birds

7. Trophic Levels

● Position an organism occupies in a food chain.

● Highest concentration: Top of food chain

● Lowest concentration: Producers

10. Energy Flow

● Unidirectional (from Sun → Producers → Consumers → Decomposers)

● Only 4–5 steps in a food chain due to energy loss at each level.So that, very little amount of usable energy remains after T4 Or T5 level. ● Highest Energy: 1st Trophic level ● Lowest Energy: Top of food chain

11. Pyramid of Energy (Always

Upright)

● Quaternary Consumers: 1J ● Tertiary Consumers: 10 J ● Secondary Consumers: 100 J ● Primary Consumers: 1,000 J ● Producers: 10,000 J

12. Environmental Problems & Management

Ozone Layer & Depletion

● Found in stratosphere ; protects from UV rays.

● Causes of Depletion: CFCs, methyl chloroform, methyl bromide

● Effects: Skin cancer, cataracts, DNA damage, lower immunity, poor crop yield

● Action Taken: 1987 Montreal Protocol – global agreement to reduce CFC production ● Depletion: ➔ CFCs emission reach the ozone layer. ➔ CFCs are broken down by UV rays, releasing chlorine atoms into the ozone layer. ➔ Active chlorine atoms break down ozone molecules, causing depletion.

13. Waste Management

Biodegradable Waste Non-Biodegradable Waste

● Recycling & 3Rs: Reuse, Reduce, Recycle solid waste like paper, metals, etc.