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B7 - Ecology (The Carbon Cycle (When plants/algae/animals die, other…

- - - - The populations of any species is usually limited by the amount of food available
      - If the population of prey increases, then so will the population of predators
      - If the population of predators increase, the population of prey decreases
    - - This is because it takes a while for one population to respond to changes in the other population
      - eg. if the number of rabbits goes up, it takes time for the number of foxes to go up as it takes time for them to reproduce
    - - eg. more grass means more rabbits which means more foxes but this then means fewer rabbits so fewer foxes and more grass...
  - - - Level 2
        
        Level 3
        
        Level 4
        
        Decomposers
        
        eg. bacteria and fungi
        
        They decompose any dead plant/animal material left in an environment
        
        they secrete enzymes that break it down into small soluble food molecules which then diffuse into the microorganisms
        
        A vital role in ecosystems - it releases nutrients into the environment which the producers need in order to grow
        
        Tertiary consumer
        
        eg. arctic wolf
        
        Apex predators are animals which have no predators - are at the top of the food chain
        
        Secondary consumer
        
        eg. arctic fox
        
        Carnivores
      - Primary consumer
      - eg. arctic hare
      - Herbivores that eat the plants/algae
  - - - Only 10% is transferred to the next level
        
        It is lost because organisms don't always eat the entire organism (eg. bones)
        
        Organisms don't absorb all of the stuff in the food they ingest (some is egested as faeces)
        
        Some of the biomass taken in is converted into other substances and lost as waste
        
        eg. the glucose (obtained from biomass) in respiration can be used for movement/keeping warm rather than making more biomass. This creates by-products (eg. CO2 & H2O)
        
        Urea is another waste produce which is released in urine with water when the proteins in the biomass are broken down
    - - efficiency = (biomass transferred to the next level/biomass available at the previous level) x 100
- - - - Space (territory)
        Food
        Water
        Mates
    - - Light
        Space
        Water
        Mineral ions (nutrients) from the soil
  - - - All the organisms of one species living in a habitat
    - - The populations of different species living in a habitat
    - - Non-living factors of the environement
    - - Living factors of the environment
    - - The interaction of a community of biotic with the abiotic parts of their environment
    - - The dependence of organisms on one another (for food, shelter, pollination and seed dispersal)
    - - When all the species and environmental factors are in balance so that the population sizes are roughly constant (eg. rainforests)
  - - - Moisture level
        Light intensity
        Temperature
        Carbon dioxide level (for plants)
        Wind intensity & direction
        Oxygen level (for aquatic animals)
        Soil pH and mineral content
      - eg. a decrease in light intensity could affect the rate of photosynthesis so could affect plant growth and cause a decrease in population size
    - - New predators arriving
        Competition (a species out-competing another so numbers are too low to breed)
        New pathogens
        Availability of food
- - - - eg. plants turn elements (carbon, oxygen, hydrogen and nitrogen) from the soil and air into the complex compounds (carbohydrates, proteins and fats) that make up living organisms. These get passed up the food chain
  - - - Warmer temperatures, decompose quicker, enzymes work faster
        Too hot, enxymes denature and the organism dies
        Cold temperatures slow the rate of decomposition
    - - Moist conditions, decompose quicker, microorganisms need water to carry out biological processes
    - - Many organisms need oxygen to respire
      - Microorganisms involved in anaerobic decay don't though
    - - The more microorganisms there are, the faster decomposition is
  - - - Sludge waste, from sewage works/sugar factories, is used to make biogas on a large scale
    - - Batch generators
        
        Manually loaded with waste, left to digest and the by-products are cleared away at the end of each session
        
        Make it in small batches
      - Continuous generators
        
        Waste is continuously fed in and its produced at a steady rate
        
        They're more suited to large-scale projects
        
        Make is continuously
    - - eg. for heating, cooking, lighting, or to power a turbine to generate electricity
    - - An inlet for waste material to be put in
      - An outlet for the digested material to be removed through
      - An outlet so that the biogas can be piped to where it is needed
- - - - By counting all the organisms you're interested in that touch the line
      - Or, by collecting data using quadrats (which can be placed next to each other along the line or at regular intervals, eg. every 2 m)
  - - - You use quadrats to measure how common an organism is in two sample areas and compare them
      - You use transects to study how the distribution changes across an area