Environment, Ecosystem and Biodiversity Notes

Environment, Ecosystem, and Biodiversity Notes

Environmental Science

  • Definition: Study of the environment which includes both biotic (living) and abiotic (non-living) components.
  • Types of Environment:
    • Natural Environment: Soil, water, air, trees, noise, etc.
    • Man-made Environment: Houses, roads, parks, etc.

Importance of Environment

  • The environment is crucial for the sustenance of life on Earth. It provides essential resources such as food, water, and air.
  • Derived from the French word "Environ," meaning "surrounding."
  • Key role: Nourishes life and integrates ecological balance.
  • World’s "natural capital" includes forests, rivers, oceans, and soils.
  • Encouragement for conservation and protection of the environment is paramount.

Components of Environment

Biotic Components:
  • Energy Components: Essential for ecosystem functioning. Examples include:
    • Solar Energy
    • Nuclear Energy
    • Geochemical Energy
    • Thermo-electrical Energy
Abiotic Components:
  • Major Components:
    • Atmosphere
    • Lithosphere
    • Hydrosphere
Atmosphere Functions:
  • Sustains life by absorbing harmful radiation (IR & UV rays).
  • Participates in the hydrological cycle by carrying water to land.
  • Provides oxygen for living beings and carbon dioxide for plant photosynthesis.

Ecosystems

  • Definition: An ecosystem is a community of living organisms interacting with each other and their non-living environment.
  • Biomes: Larger ecological areas (e.g., forests, grasslands) sharing similar climate and life forms.
  • Energy Flow in Ecosystems:
    • Energy flows unidirectionally from producers to consumers.
    • Energy loss occurs at each trophic level (approx. 80% energy lost per trophic transfer).
    • Autotrophs (Producers) create energy from sunlight; Heterotrophs (Consumers) obtain energy from other organisms.

Nutrient Cycles

Carbon Cycle:
  • Key processes: Photosynthesis, respiration, and decomposition.
  • Cycling of carbon between atmosphere, living organisms, and oceans.|
Nitrogen Cycle:
  • Involves nitrogen fixation, assimilation, ammonification, and denitrification.
Phosphorus Cycle:
  • Slow cycle due to the absence of a gaseous phase.
  • Movement through organisms, soil, and water is vital for biological processes.

Trophic Levels

  • Definition: Position of organisms in a food chain, indicating energy flow.
    • Producers: First trophic level (e.g., plants)
    • Primary consumers: Herbivores (second level)
    • Secondary consumers: Carnivores/omnivores (third level)
    • Tertiary consumers: Top carnivores (fourth level)

Food Chains and Food Webs

  • Food Chain: Linear representation of energy flow between organisms.
  • Food Web: Complex network of food chains indicating the interrelatedness of organisms.
  • Biomagnification: Accumulation of toxins at successive trophic levels (e.g., DDT).

Ecological Succession

  • Types:
    1. Primary Succession: Establishment of a biological community in a previously uninhabited area.
    2. Secondary Succession: Recovery of a biological community following disturbance.
  • Autogenic Succession: Changes in the environment caused by the community itself.

Biodiversity

  • Definition: Variety of life on Earth, including genetic, species, and ecosystem diversity.
  • Levels of Biodiversity:
    • Genetic Diversity: Variability of genes within species.
    • Species Diversity: Variety and abundance of species within a community.
    • Ecosystem Diversity: Range of different ecosystems and ecological processes.
  • Importance: Essential for ecosystem resilience and human well-being.

Conservation of Biodiversity

  • Goals:
    1. Maintain ecological processes.
    2. Preserve species diversity.
    3. Ensure sustainable resource utilization.
  • Methods:
    • In situ conservation: Protecting natural habitats and ecosystems (e.g., national parks).
    • Ex situ conservation: Preservation of species outside their natural habitats (e.g., zoos, botanical gardens).

Threats to Biodiversity

  • Habitat destruction, climate change, pollution, and overexploitation of species.
  • Endangered species are at risk due to human activities, requiring urgent conservation efforts.

Hotspots of Biodiversity in India

  • Notable Areas: Eastern Himalayas, Western Ghats.
  • Significance: High levels of endemic species and vulnerability to environmental threats.