Ecology

• Ecology is the study of the relationships between organisms and their environment
• An ecosystem is a community of living organisms (plants, animals and microorganisms) 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 (sometimes)
• 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 of organisms


  • Cacti have shallow roots, spines, and can store water in their leaves to survive in the desert
  • Snow foxes have white fur, small ears, and a thick coat to survive in cold environments
• Energy flow in an ecosystem

  1. Sun provides energy

  2. Plants grow using energy from the sun

  3. Plants are eaten by other organisms

  4. Organisms are eaten by top consumers
• Quadrat

  A square frame used to estimate the size and population of plants in a field
• Transect

  A line along which measurements are taken at regular intervals, used to study how factors change with distance
• Organic compounds


  Any compound that contains carbon
• Carbon cycle

  1. Carbon dioxide in air

  2. Absorbed by plants through photosynthesis

  3. Incorporated into organic compounds in plants and animals

  4. Returned to atmosphere through respiration and decomposition

  5. Stored in fossil fuels
• Water cycle

  1. Water evaporates from surface

  2. Water vapour condenses to form clouds

  3. Precipitation falls as rain, snow, etc.

  4. Water flows into rivers and oceans

  5. Water is taken up by plants and transpired
• Microorganisms

  • They break down organic matter through decay and decomposition
  • Their activity is affected by temperature, water, and oxygen levels
• Composting allows nutrients from organic matter to be recycled back into the garden
• Biodiversity

  The range of plants and animals that live within a habitat
• Human activities such as deforestation, pollution, and climate change can have a dramatic impact on biodiversity
• Peat

  A type of soil that forms over millions of years and provides a habitat for plants and animals
• Burning peat as fuel destroys the habitat it provides
• Greenhouse gases

  • Carbon dioxide
  • Water
  • Methane
• Global warming and climate change can have diverse impacts on different regions, affecting habitats and food sources for organisms
• Trophic levels

  The different levels in a food chain, with producers at the bottom and top consumers at the top
• Only about 10% of energy is transferred from one trophic level to the next
• Food security

  The availability of and access to sufficient, safe, and nutritious food
• Measures to increase food production, such as using fertilizers, need to consider the environmental impact
• Sustainable fishing practices, such as using appropriate net sizes and following quotas, can help ensure food security
• Culturing microorganisms is a new way of developing food sources