B7 ecology

• Individual


  Part of a species, lives in its habitat within a population
• Community


  Many different populations interact in the same habitat
• Ecosystem


  Interaction of a community with non-living (abiotic) parts of the environment
• Organisms


  • Adapted to live in the conditions of their environment
• Competition


  Can be within a species or between different species
• Competition between plants


  • For light, space, water and mineral ions
• Competition between animals


  • For space, food, water and mating partners
• Interdependence


  Organisms in a community depend on other organisms for vital services like food, shelter and reproduction
• Removal or addition of a species to the community can affect the populations of others greatly, as it changes prey or predator numbers
• Stable community


  Biotic (living) and abiotic (non-living) factors are in balance, population sizes remain roughly constant
• Stable communities


  • Tropical rainforests, oak woodlands, coral reefs
• Abiotic factor


  Non-living factor that can affect a community
• Abiotic factors


  • Light intensity
  • Temperature
  • Moisture levels
  • Soil pH and mineral content
  • Wind intensity and direction
  • Carbon dioxide levels
  • Oxygen levels for aquatic animals
• Biotic factor


  Living factor that can affect a community
• Biotic factors


  • Food availability
  • New predators
  • New pathogens
  • Competition
• Adaptation


  Allows organisms to survive in the conditions where they live
• Types of adaptations


  • Structural
  • Behavioural
  • Functional
• Extremophiles


  Organisms that live in environments with extreme conditions
• Adaptations for cold climates

  • Smaller surface area to volume ratio, lots of insulation
• Adaptations for dry climates

  • Adaptations to kidneys to retain water, active in early morning/evening, larger surface area ratio
• Plant adaptations


  • Curled leaves, extensive root systems, waxy cuticle, water storing tissue
• Producer


  Photosynthetic organism that makes glucose through photosynthesis
• Primary consumer


  Eats the producer
• Secondary consumer


  Eats the primary consumer
• Tertiary consumer


  Eats the secondary consumer
• Transect


  Tool used to work out the distribution and abundance of species in an ecosystem
• Quadrat


  Tool used to work out the distribution and abundance of species in an ecosystem
• A stable community will show population cycles between the predators and prey
• Carbon cycle


  CO2 is removed from the air in photosynthesis and returned to the air through respiration and combustion
• Water cycle


  Water evaporates, forms clouds, precipitates, and runs into seas to repeat the cycle
• Factors affecting decomposition rate

  • Temperature
  • Water
  • Availability of oxygen
• Compost


  Produced when biological material decays, used as a natural fertiliser
• Methane gas


  Produced by microorganisms decomposing waste anaerobically, can be burnt as a fuel
• Biogas generators


  Used to produce methane, require constant temperature
• Environmental changes affect the distribution of species in an ecosystem
• Examples of environmental changes

  • Temperature changes
  • Water availability changes
  • Atmospheric gas composition changes
• Biodiversity


  Variety of different species of organisms on Earth or within an ecosystem
• High biodiversity means the ecosystem will be stable
• Many human activities are having a negative effect on biodiversity
• Examples of human activities negatively affecting biodiversity

  • Using more land for houses, farming, shops, roads and factories
  • Pollution (sewage, fertiliser, toxic chemicals, smoke, acidic gases)
  • Using up raw materials quicker than they are being produced