Ecology

• Ecology is the study of the relationships between organisms and their environment
• An ecosystem is a community of living organisms (plants and animals) interacting with each other and their physical environment
• Organisms in an ecosystem depend on each other and cannot survive without each other
• Factors that affect organisms


  • Food
  • Water
  • Air
  • Mate
• Abiotic factors


  Non-living factors that affect organisms, such as light intensity, temperature, water levels, pH, iron levels, wind, carbon dioxide levels, oxygen levels
• Biotic factors


  Living factors that affect organisms, such as food, predators, pathogens
• Changes in abiotic or biotic factors


  Can have a dramatic impact on a community
• Adaptations


  • Cacti have shallow roots, spines, and can store water to survive in the desert
  • Snow foxes have white fur, small ears, and thick coats to survive in cold environments
• Food chain


  1. Sun provides energy

  2. Plants grow and are eaten by other organisms

  3. Animals eat plants or other animals

  4. Humans eat plants or animals directly or processed
• Quadrat


  A square frame used to estimate plant population in a field
• Transect


  A line along which measurements are taken at regular intervals, e.g. to measure changes in light intensity or distance from water
• Organic compounds


  Any compound that contains carbon
• Carbon cycle


  1. Carbon dioxide in air

  2. Carbon in oceans

  3. Carbon in organic compounds in plants and animals

  4. Carbon in dead plants and animals

  5. Carbon in fossil fuels

  6. Combustion

  7. Photosynthesis

  8. Respiration

  9. Decay
• Water cycle


  1. Evaporation from surface water

  2. Condensation to form clouds

  3. Precipitation as rain

  4. Percolation into soil and mountains

  5. Surface runoff

  6. Uptake by plants

  7. Transpiration
• Microorganisms


  • Involved in decay and decomposition
  • Affected by temperature, water, and oxygen levels
• Compost gets hot and smelly as microorganisms break down organic matter
• Biodiversity


  The range of plants and animals that live in a habitat
• Humans have a major impact on biodiversity through activities like deforestation and pollution
• Peat


  A type of mud that forms over millions of years and provides a habitat for plants and animals
• Burning peat as fuel destroys its habitat
• Global warming


  An increase in average global temperatures leading to climate change, with some areas getting hotter, colder, drier, or windier
• Global warming


  Impacts animal habitats and food sources, e.g. melting ice caps affecting polar bears
• Trophic levels


  The different levels in a food chain, with roughly 10% of energy transferred from one level to the next