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3.5- Population size and ecosystem - Coggle Diagram

- - - - - Abiotic factor (non-living)
        Include temperature, pH, light intensity and water availability
      - - Biotic factors (living)
        Competiton for limited resources between members of the same species (interspecies competition)
        competition between organisms of different species (intraspecific competiton).
        New diseases, paraitism.
        An increase in predator numbers
    - - Number of prey can limit the population growth of predator population. The number of predators can limit the population growth of a prey population. Predator-prey interactions cause both populations to vary due to negative feedback mechanism
  - - - Population growth = (Birth+immigration)-(Death + Emigration)
- - - - Producers (trophic level 1) autotrophic organisms (plants and algae) which absorb light energy to convert simple inorganic compounds into more complec organic compounds such as carbohydrate.
      - Consumers, heterotrphic organisms which cannot fix carbon from inorganic sources like producers do - they must ingest or absorb organic carbon from other organisms.
      - Herbivores (primary consumers at trophic level 2) - Animals which feed on organic matter to produced by the producers.
      - Carnivores, Feed on the animals of lower trophic levels.
      - Tophic level, an organisms position within the food chain.
      - Detritivores, (earthworms, woodlice and maggots), feed on dead organic matter e.g - dead plants and animals.
      - Decomposers, such as bacteria and fungi, break down organic compounds into simpler inorganic compounds, which are soluble and can be absorbed by plant roots.
    - - Much of the energy which reaches the producers as sunlight is never absorbed and is therefore unavailable for photosynthesis.
      - Light is refected from the leaf surface
        
        Wrong wavelength of light which cannot be absorbed by the photosynthesis pigments
        
        Light passes through the leaf and does not hit the photosynthetic pigments
      - Energy absorbed and fixed into carbohydrate by producers is lost as heat due to respiration
        
        Cellulose in plant wall cells cannot be digested by herbivores as they do not produce the enzyme cellulase; this energy source is lost as waste, but it is made availiable to the decomposers.
      - Photosynthetic efficiency
        PE = Quantity of light energy incorporated into biomass/Quantity of light energy hitting the leaf