Topic 7 – Ecology

• Ancestor


  The more recent, the closer related they are
• Ecological levels


  • Habitat
  • Population
  • Community
  • Ecosystem
• Biotic factors


  • Predator
  • Prey
  • Competition
  • Pathogen
• Abiotic factors


  • Moisture
  • Temperature
  • pH
  • Minerals in soil
  • Wind
• Interdependence


  Depending on other species for survival (e.g. pollination)
• Stable community


  Constant population size (materials out = materials in)
• Adaptations


  • Structural
  • Behavioural
  • Functional
• Behavioural adaptations


  • Migration (new climate)
  • Penguin huddle (warmth)
  • Elephant flaps ears (cooling)
• Functional adaptations


  • Hibernation
  • Metabolism
  • Concentrated urine
• Extremophiles


  Microorganisms adapted to live in extreme conditions
• Trophic levels


  • Producer
  • Primary consumer
  • Secondary consumer
  • Tertiary consumer
• Biomass


  The mass of living material
• Less predators


  More food, less competition, more predators
• More predators


  Food eaten, less food, more competition, less predators
• Quadrat


  1m by 1m frame used to study distribution of organisms
• Using quadrats to estimate population size

  1. Draw map of area

  2. Pick coordinates using random number generator

  3. Place quadrat

  4. Count organisms inside

  5. Repeat

  6. Calculate mean
• Transect


  Two points joined by a line to measure distribution along a line
• Disadvantages of quadrats/transects: Not accurate for moving organisms
• Factors affecting distribution


  • Temperature
  • Water availability
  • Gases in the air
• Water cycle


  1. Energy from sun evaporates water

  2. Transpiration evaporates water

  3. Water vapour condenses into clouds

  4. Precipitation as rain/hail/snow
• Carbon cycle


  1. Photosynthesis (CO2 into plants)

  2. Respiration (CO2 released)

  3. Eating (carbon from plants to animals)

  4. Decay (CO2 released)

  5. Combustion (CO2 released)
• Detritus feeders


  Micro-organisms that breakdown dead/waste materials
• Compost


  Natural fertilisers made from broken down organic matter
• Factors affecting rate of decay

  • Temperature
  • Oxygen
  • Water
  • Number of decomposers
• Methane


  Made from anaerobic decay of waste material by microorganisms
• Biogas generators


  • Batch (small batches, manually loaded)
  • Continuous (large scale, continuously producing)
• Practical investigation on rate of decay

  1. Set up test tubes with lipase, milk, phenolphthalein

  2. Measure time for colour change

  3. Repeat at different temperatures
• Biodiversity


  The variety of living organisms within an ecosystem
• Causes of decreasing biodiversity

  • Deforestation
  • Waste production
  • Global warming
• Benefits of biodiversity


  • Medicines
  • Technology
  • Farming
  • More demand on environment
• Greenhouse effect


  1. Infrared radiation from Sun

  2. CO2 allows short wavelengths to pass

  3. CO2 absorbs long wavelengths

  4. Reflects back into Earth

  5. Raising global temperature
• Dangers of global warming

  • Rising sea levels
  • Change in rainfall and temperature patterns
  • Changes in migration patterns
  • Reduce biodiversity
• Pros and cons of deforestation


  • Pros: Raw materials, more land for cattle/crops, less CO2 taken in

  Cons: CO2 released, reduced biodiversity, less habitats
• Pros and cons of protecting biodiversity

  • Pros: Breeding programmes, protect habitats, prevent deforestation, reduce/reuse/recycle

  Cons: Wastes government money, less deforestation = unemployment, some animals shouldn't be protected, land in high demand
• Trophic levels


  • Producer
  • Primary consumer
  • Secondary consumer
  • Tertiary consumer
• Pyramid of biomass


  Shows the relative mass of each trophic level
• Reasons for energy loss in food chains

  • Respiration (heat)
  • Movement
  • Inedible parts
  • Faeces
  • Not all food eaten
• Methods to control overfishing

  • Fishing quotas
  • Larger net size
• Methods to increase food production efficiency

  • Limit animal movement
  • Control temperature
  • Feed high protein food
• Mycoprotein


  Protein meat-alternative for vegetarians, made by growing fungi on glucose