Ecology

Ecology Cycles

Biotic Factors

• Definition: Any living thing that possesses all characteristics of life.
• Characteristics:
  • Composed of cells.
  • Exhibits levels of organization.
  • Engages in metabolism/respiration (uses energy).
  • Responds to the environment (maintains homeostasis).
  • Grows and reproduces.
  • Adapts to the environment.

Abiotic Factors

• Definition: Nonliving components that do not have all characteristics of life.
  • Note: May exhibit some characteristics but are still classified as nonliving.

Ecology Overview

• Definition: The study of organisms and their interactions within their environment.
• Ecosystem: Combination of all living (biotic) and physical/nonliving (abiotic) factors within a specific area.
  • Classified based on:
  • Plants
  • Animals
  • Climate

Ecological Cycles

1. Water Cycle
2. Carbon Cycle
3. Nitrogen Cycle

Carbon Cycle

• Components Involved:
  • Photosynthesis
  • Decay of organisms
  • Sunlight
  • CO₂ cycle
  • Organic carbon (e.g., derived from living organisms)
  • Animal Respiration: Returns carbon to the atmosphere.
  • Plant Respiration: Similar function as animal respiration.
  • Fossil Fuels: Converted from dead organisms over millions of years.
  • Ocean Uptake: Oceans absorb CO₂ from the atmosphere.

Characteristics of the Carbon Cycle

• Cycles between biotic (living) and abiotic (nonliving) factors.
  • Organic carbon sources include animals and plants.
  • Inorganic sources include rocks, atmosphere, and water.
• Importance: Carbon is the building block of all living things and is essential for life on Earth.

Greenhouse Effect (GHE)

• Mechanism: Greenhouse gases (GHGs) trap and emit heat (infrared radiation), keeping Earth enviably warm.
• Significance:
  • Maintains habitable conditions on Earth.
  • Historical fluctuations have influenced global climates and contributed to glacial and interglacial periods.

Key Terms for the Carbon Cycle

• Source: An area that releases more carbon than it absorbs.
• Sink: An area that absorbs more carbon than it releases; can be referred to as a reservoir.
  • Includes atmosphere, ocean, and biosphere.
  • Largest carbon sink: Deep ocean.

Timeframes of Carbon Cycling

• Very Fast (less than 1 year): Plant growth and decay, microbial activity.
• Fast (1-10 years): Carbon cycling through biosphere, including food chains.
• Slow (10-100 years): Carbon release from fossil fuels.
• Very Slow (over 100 years): Carbon captured in sediments and fossilized materials.

Carbon Cycle Processes

• Photosynthesis:

  • Conversion: ( \text{Carbon Dioxide} + \text{Water} + \text{Light Energy} \rightarrow \text{Glucose} + \text{Oxygen} )
  • Performed by plants utilizing chloroplasts.

• Cellular Respiration:

  • Conversion: ( \text{Glucose} + \text{Oxygen} \rightarrow \text{Carbon Dioxide} + \text{Water} + ATP )
  • Occurs in plants and animals, using mitochondria.

• Other Processes:

  • Decomposition: Breaks down organisms and reintroduces CO₂ into the atmosphere.
  • Dissolution: CO₂ absorbed by oceans.
  • Lithification: Process leading to fossil fuel creation.
  • Combustion: Releases CO₂ by burning organic material.

Common Natural Compounds in the Carbon Cycle

• Carbon Dioxide (CO₂): Present in the atmosphere, absorbed by plants.
• Glucose (C₆H₁₂O₆): Produced in photosynthesis, utilized in respiration.
• Methane (CH₄): A potent greenhouse gas primarily from agriculture and livestock.
• Carbon Monoxide (CO): Produced from fossil fuel combustion.
• Calcium Carbonate (CaCO₃): Found in shells and limestone, forms sedimentary rocks.

Carbon Sequestration

• Definition: Long-term storage of carbon in natural sinks (e.g., oceans, forests) to slow atmospheric CO₂ buildup.
  • Natural Sinks: Include deep oceans and forests.
  • Man-Made Methods: Rereforestation, forest protection, carbon capture and storage.

Nitrogen Cycle

• Main Components:
  • Nitrogen Fixation: Conversion of atmospheric N₂ into a usable form for plants, facilitated by nitrogen-fixing bacteria and lightning.
  • Denitrification: Breakdown of nitrogen compounds in soil by bacteria, returning N₂ to the atmosphere and preventing excess nitrogen buildup.

Nitrogen Cycle Processes

• Assimilation: Uptake of usable nitrogen by plants and animals for protein and nucleic acid synthesis.
• Decomposition: Conversion of organic nitrogen from organisms into inorganic forms accessible to plants.
  • Key focus: Ammonification during decomposition.