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Practice MCQ

Unit 6 - Notes

GEO295

Unit 6: Environmental Geography

1. Principles of Ecology

Ecology is the scientific study of the interactions between organisms and their environment. It encompasses the study of individuals, populations, communities, ecosystems, and the biosphere.

A. The Ecosystem Concept

An ecosystem is a structural and functional unit of ecology where living organisms interact with each other and the surrounding physical environment.

  • Components of an Ecosystem:
    • Abiotic (Non-living): Physical and chemical factors (Temperature, Light, Water, Soil, Nutrients, pH).
    • Biotic (Living):
      • Producers (Autotrophs): Synthesize food via photosynthesis (green plants, algae) or chemosynthesis (some bacteria).
      • Consumers (Heterotrophs): Depend on others for food.
        • Primary: Herbivores.
        • Secondary/Tertiary: Carnivores and Omnivores.
      • Decomposers (Saprotrophs): Break down organic matter (bacteria, fungi), recycling nutrients back to the soil.

B. Energy Flow in Ecosystems

Energy flows unidirectionally from the sun to producers and then to consumers.

  • Laws of Thermodynamics:
    1. First Law: Energy cannot be created or destroyed, only transformed (Solar Chemical).
    2. Second Law: Energy transformation is inefficient; entropy increases.
  • 10% Law (Lindeman): Only about 10% of energy is transferred from one trophic level to the next; the rest is lost as heat (respiration).
  • Food Chain: A linear sequence of organisms where nutrients and energy are transferred (e.g., Grass Grasshopper Frog Snake).
  • Food Web: A complex network of interconnected food chains, representing greater stability in an ecosystem.

C. Biogeochemical Cycles

The movement of nutrient elements through the various components of an ecosystem.

  1. Gaseous Cycles: Reservoir is the atmosphere or hydrosphere (Nitrogen, Carbon, Oxygen).
  2. Sedimentary Cycles: Reservoir is the earth's crust (Phosphorus, Sulphur).

D. Ecological Succession

The process of change in the species structure of an ecological community over time.

  • Primary Succession: Occurs in lifeless areas (e.g., new lava, retreating glacier). Starts with Pioneer Species (lichens/mosses).
  • Secondary Succession: Occurs in areas where a community previously existed but was removed (e.g., forest fire, harvested crop land).
  • Climax Community: The final, stable stage of succession (e.g., a mature rainforest).

2. Environmental Degradation

Environmental degradation is the deterioration of the environment through depletion of resources like air, water, and soil; the destruction of ecosystems; and the extinction of wildlife.

A. Causes of Degradation

  • Natural Causes: Volcanic eruptions, earthquakes, cyclones, forest fires (lightning).
  • Anthropogenic (Human) Causes:
    • Population Explosion: Increased demand on resources.
    • Urbanization: Habitat fragmentation and "Heat Island" effect.
    • Industrialization: Release of toxins and greenhouse gases.
    • Agricultural Expansion: Monocultures, pesticide overuse, irrigation salinity.

B. Types of Degradation

  1. Land/Soil Degradation:
    • Soil Erosion: Removal of topsoil by wind or water.
    • Desertification: Transformation of arable land into desert due to overgrazing and deforestation.
    • Salinization: Accumulation of salts in soil due to improper irrigation.
  2. Water Degradation:
    • Eutrophication: Nutrient enrichment (N, P) leading to algal blooms and oxygen depletion (hypoxia).
    • Bioaccumulation: Accumulation of toxins (e.g., Mercury, DDT) in organisms.
  3. Atmospheric Degradation:
    • Particulate Matter (PM 2.5/10): Respiratory issues.
    • Acid Rain: Caused by and reacting with water vapor.
    • Ozone Depletion: Caused by CFCs, leading to increased UV radiation.

3. Biodiversity and Sustainable Development

A. Biodiversity

The variety of life on Earth at all levels, from genes to ecosystems.

  • Levels of Biodiversity:
    1. Genetic Diversity: Variation within a species.
    2. Species Diversity: Variety of species in a region.
    3. Ecosystem Diversity: Variety of habitats and ecological processes.
  • Biodiversity Hotspots: Regions with high species richness and high endemism (species found nowhere else) that are under threat (e.g., Western Ghats, Amazon).
  • Threats (HIPPO Acronym):
    • Habitat Loss (Main driver).
    • Invasive Species.
    • Pollution.
    • Population Growth (Human).
    • Overexploitation (Hunting/Fishing).

B. Sustainable Development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs (Brundtland Commission, 1987).

  • Three Pillars:
    1. Economic: Growth, efficiency, stability.
    2. Social: Equity, poverty reduction, culture.
    3. Environmental: Biodiversity, clean resources, ecosystem integrity.
  • Sustainable Development Goals (SDGs): 17 global goals set by the UN in 2015 for the year 2030 (e.g., No Poverty, Climate Action, Life Below Water).

4. Management and Conservation

A. Conservation Strategies

  1. In-situ Conservation (On-site):
    • Protecting species in their natural habitat.
    • Examples: National Parks, Wildlife Sanctuaries, Biosphere Reserves, Sacred Groves.
    • Advantage: Preserves the ecosystem and evolutionary processes.
  2. Ex-situ Conservation (Off-site):
    • Protecting species outside their natural habitat.
    • Examples: Zoos, Botanical Gardens, Seed Banks, Cryopreservation, Gene Banks.
    • Advantage: Prevents immediate extinction; allows for breeding programs.

B. Resource Management Techniques

  • Forests: Afforestation, Reforestation, Social Forestry, Joint Forest Management (JFM).
  • Water: Rainwater harvesting, Watershed management, Drip irrigation.
  • Soil: Terracing, Contour farming, Crop rotation, Mulching.

5. Environmental Policy, Education, and Legislation

A. International Protocols and Conventions

  • Stockholm Conference (1972): First major UN conference on international environmental issues.
  • Montreal Protocol (1987): To phase out Ozone Depleting Substances (ODS) like CFCs.
  • Rio Earth Summit (1992): Produced Agenda 21, CBD (Convention on Biological Diversity), and UNFCCC.
  • Kyoto Protocol (1997): Binding targets for developed nations to reduce Greenhouse Gases (GHG).
  • Paris Agreement (2015): Aim to keep global temperature rise well below 2°C pre-industrial levels.

B. Environmental Impact Assessment (EIA)

A tool used to identify the environmental, social, and economic impacts of a project prior to decision-making.

  • Steps: Screening Scoping Impact Analysis Mitigation Reporting Public Hearing Decision making.

C. Environmental Education

  • Objective: To create awareness, knowledge, attitude, skills, and participation regarding environmental challenges.
  • Non-formal Education: NGOs, media campaigns, eco-clubs.
  • Formal Education: Curriculums in schools and universities (multidisciplinary approach).

D. Legislation (General Framework)

  • Polluter Pays Principle: Those who produce pollution should bear the costs of managing it.
  • Precautionary Principle: If an action has a suspected risk of causing harm to the public or the environment, the burden of proof that it is not harmful falls on the acting party.

6. Environmental Hazards and Remedial Measures

A. Hazards vs. Disasters

  • Hazard: A dangerous phenomenon, substance, human activity, or condition that may cause loss of life, injury, or other health impacts (The Potential).
  • Disaster: A serious disruption of the functioning of a community involving widespread losses that exceed the ability of the affected community to cope using its own resources (The Event).
  • Equation:

B. Classification of Hazards

  1. Geophysical: Earthquakes, Landslides, Tsunamis, Volcanic activity.
  2. Hydrometeorological: Floods, Cyclones/Hurricanes, Droughts, Heatwaves.
  3. Biological: Epidemics, Insect infestations.
  4. Technological/Man-made: Nuclear leaks (Chernobyl), Chemical spills (Bhopal Gas Tragedy), Dam failures.

C. Disaster Management Cycle

  1. Pre-Disaster:
    • Mitigation: Structural (dams, retrofitting) and Non-structural (zoning laws, awareness).
    • Preparedness: Early warning systems, evacuation plans, stockpiling supplies.
  2. During Disaster:
    • Response: Search and rescue, providing immediate relief (food, shelter, medical aid).
  3. Post-Disaster:
    • Recovery: Rehabilitation (restoring basic services) and Reconstruction (long-term rebuilding).

D. Specific Remedial Measures

  • Flood Management: Construction of levees, dredging rivers, floodplain zoning, afforestation in upper catchments.
  • Drought Management: Drought-resistant crops, water rationing, cloud seeding (limited efficacy), interlinking of rivers (controversial).
  • Earthquake Remedial: Seismic retrofitting of buildings, base isolation techniques, strict adherence to building codes.
  • Landslide Remedial: Retaining walls, drainage control, afforestation on slopes, restricting construction on unstable slopes.