TJ

In-Depth Ecology Cycles Notes

Key Concepts in Ecology Cycles

Biotic Factors

  • Definition: Any living thing exhibiting all characteristics of life, which include:
    • Composed of cells
    • Organized at multiple levels (tissues, organs, etc.)
    • Utilize energy through metabolism and respiration
    • Respond to environmental changes (homeostasis)
    • Grow and reproduce
    • Adapt to their environment

Abiotic Factors

  • Definition: Nonliving elements that do not possess all characteristics of life. They may exhibit some characteristics but are fundamentally nonliving.
  • Examples include minerals, weather, and sunlight.

Ecology

  • Definition: The study of organisms and their interactions with their environment.
  • Ecosystem: Composed of biotic (living) and abiotic (nonliving) factors within a particular area, classified based on plant, animal types, and climate.
  • Ecological Cycles: Major cycles include:
    • Water Cycle
    • Carbon Cycle
    • Nitrogen Cycle

Carbon Cycle

  • Key Components:
    • Involves the exchange between biotic factors (like plants and animals) and abiotic factors (such as rocks, atmosphere, and water).
    • Carbon is fundamental to all life forms on Earth.
  • Sources and Sinks:
    • Source: Releases more carbon dioxide (CO₂) than it absorbs.
    • Sink: Absorbs more CO₂ than it releases, contributing to long-term carbon storage (reservoirs), e.g., oceans, deep ocean being the largest carbon sink.

The Greenhouse Effect

  • A natural process where greenhouse gases (GHGs) trap heat (Infrared radiation) to maintain a habitable Earth temperature.
  • Historical Impact: Fluctuates and has influenced historical climate patterns, contributing to glacial and interglacial periods.

Carbon Cycle Processes

  1. Photosynthesis:
    • Plants absorb CO₂ and release oxygen.
    • Equation: Carbon Dioxide + Water + Light → Glucose + Oxygen.
  2. Cellular Respiration:
    • Organisms absorb oxygen and release CO₂.
    • Equation: Glucose + Oxygen → Carbon Dioxide + Water + ATP (energy).
  3. Decomposition:
    • Breaks down organisms, releasing CO₂ into the atmosphere.
  4. Dissolution:
    • CO₂ from the atmosphere dissolves in the ocean.
  5. Lithification:
    • Formation of fossil fuels trapped in sedimentary rocks.
  6. Combustion:
    • Burning of organic matter releases CO₂.

Common Compounds in the Carbon Cycle

  • Carbon Dioxide (CO₂): Emitted by humans, absorbed by plants.
  • Glucose (C6H12O6): Produced during photosynthesis, used in cellular respiration.
  • Methane (CH₄): Strong GHG, produced by livestock and certain farming practices, often trapped in permafrost.
  • Calcium Carbonate (CaCO₃): Found in shells, limestone, forming sedimentary rocks.

Carbon Sequestration

  • Definition: Long-term storage of carbon in sinks to reduce atmospheric CO₂ levels.
  • Natural Sinks: Include forests, deep ocean, and soils.
  • Man-Made Methods: Reforestation, carbon capture and storage, and protection of forests.

Nitrogen Cycle

  • Key Components:
    • Nitrogen Fixation: Conversion of atmospheric nitrogen (N₂) into forms usable by plants, occurring through nitrogen-fixing bacteria or lightning.
    • Denitrification: Process where soil nitrogen compounds are converted back into N₂ gas, released into the atmosphere, preventing nitrogen build-up.
    • Assimilation: Plants and animals obtain nitrogen from soil for protein and nucleic acids.
    • Decomposition: Converts organic nitrogen into inorganic nitrogen (ammonification) accessible to plants.

Summary of Nitrogen Cycle Processes

  • Nitrogen Fixation: Conversion of atmospheric nitrogen to soil usable forms, aided by specific bacteria or lightning.
  • Denitrification: A microbial process converting nitrogen in the soil back to atmospheric nitrogen.
  • Assimilation: Uptake of nitrogen by plants (via soil) and animals (by consuming plants).
  • Decomposition: Breakdown of organic nitrogen compounds into simpler forms for plants to utilize.