Class 10 Science Our Environment Notes

Class 10 Science Our Environment Notes

Introduction

  • Environment refers to everything around us, including both living and non-living components.
  • Our environment is essential for our survival, providing air, water, food, and shelter.

1. Components of the Environment

Biotic Components (Living Components)

  • Producers: Organisms that produce their own food, usually through photosynthesis (e.g., plants, algae).
  • Consumers: Organisms that depend on others for food (e.g., herbivores, carnivores, omnivores).
  • Decomposers: Organisms that break down dead matter (e.g., fungi, bacteria).

Abiotic Components (Non-living Components)

  • Air, Water, Soil, Temperature, and Light are the essential abiotic factors that support life on Earth.
  • They influence the living organisms and their ecosystems.

2. Ecosystem

  • An ecosystem is a community of living organisms interacting with each other and their environment.
  • Examples of Ecosystems:
    1. Forest Ecosystem
    2. Aquatic Ecosystem (e.g., ponds, oceans)
    3. Desert Ecosystem
    4. Grassland Ecosystem

Types of Ecosystems

  • Natural Ecosystems: These occur naturally without human interference, such as forests and oceans.
  • Artificial Ecosystems: These are man-made, like farms, gardens, and aquariums.

3. Food Chain and Food Web

Food Chain

  • A food chain shows the flow of energy in an ecosystem from producers to consumers.
  • Example of a simple food chain:
    • Sun → Grass (Producer) → Rabbit (Primary Consumer) → Fox (Secondary Consumer)

Food Web

  • A food web consists of several interconnected food chains in an ecosystem. It shows how energy flows through different organisms.
  • It represents the complexity of feeding relationships in an ecosystem.

4. Bio-geo Chemical Cycles

  • Biogeochemical cycles are the natural cycles through which essential elements (carbon, nitrogen, oxygen, water, etc.) are recycled in the ecosystem.

Important Cycles:

  1. Water Cycle (Hydrological Cycle):
    • Involves the continuous movement of water through evaporation, condensation, precipitation, and infiltration.
  2. Carbon Cycle:
    • Carbon is cycled through living organisms, the atmosphere, and the soil.
    • Photosynthesis and respiration play key roles in this cycle.
  3. Nitrogen Cycle:
    • Nitrogen is converted into usable forms (like nitrates and nitrites) by bacteria, and then utilized by plants and animals.

5. Pollution and Its Impact

  • Pollution refers to the introduction of harmful substances into the environment, causing damage to ecosystems and human health.

Types of Pollution

  1. Air Pollution:
    • Caused by harmful gases like carbon dioxide, sulfur dioxide, nitrogen oxides, and particulate matter.
    • Sources: Industrial emissions, vehicle exhaust, burning of fossil fuels.
  2. Water Pollution:
    • Contamination of water bodies with pollutants like chemicals, sewage, and plastic waste.
    • Sources: Industrial waste, agricultural runoff, untreated sewage.
  3. Soil Pollution:
    • The presence of toxic substances like pesticides, heavy metals, and plastics in the soil.
    • Sources: Industrial waste, improper disposal of waste, use of chemical fertilizers.
  4. Noise Pollution:
    • Unwanted sound that harms living organisms, especially in urban areas.
    • Sources: Traffic, industries, loudspeakers, construction activities.

6. Environmental Conservation

  • Conservation refers to the careful management of resources to prevent their depletion and to protect ecosystems.

Methods of Conservation:

  1. Afforestation and Reforestation: Planting trees to restore lost forests.
  2. Reduce, Reuse, Recycle: Minimizing waste and reusing materials to prevent pollution.
  3. Sustainable Agriculture: Practices like organic farming, crop rotation, and avoiding the overuse of fertilizers.
  4. Wildlife Conservation: Protecting endangered species and their habitats.

7. Ozone Layer and Global Warming

Ozone Layer:

  • The ozone layer is a layer of ozone gas (O₃) in the stratosphere that protects life on Earth by absorbing harmful ultraviolet (UV) radiation from the Sun.

Global Warming:

  • Global warming refers to the gradual increase in the Earth’s average temperature due to human activities like burning fossil fuels, deforestation, and industrial processes.
  • Impact: Melting ice caps, rising sea levels, and extreme weather patterns.