Ecology

• Ecology

  The study of interactions of organisms and their environment
• ecosystem

  clearly distinguished organisms that interact with their environment (grassland)
• habitat 


  place where an animal/plant lives eg. fox in burrow
• biosphere

  part of the earth where life exists
• eg of biosphere

  little on rock surface
• community

  different populations living in an ecosystem
• population

  members of the same species living in a habitat
• niche

  functional role of organisms in a habitat
• abiotic

  non-living factors
• Biotic 


  Living factors
• edaphic 


  effects of soil
• Food chain


  Sequence of organisms where one is eaten. But the other
• Food web

  2 or more interlinked food chains
• pyramid of numbers

  number of organisms of each stage in a food chain
• trophic level

  feeding stage of an organism in a pyramid of numbers
• limitations of a pyramid of numbers

  not actual numbers, not drawn to scale , does not take into consideration the size of the organism
• Example of predictor prey

  Fox and rabbit
• predation

  the catching killing and eating of another organism
• prey 


  the organism that’s caught killed and eaten
• Competition


  Organisms actively struggle for a resource that is in short supply
• scramble competition

  a struggle where both organisms get equal amount of the resourse eg, grass and rushed both get sunlight
• competition

  physical fight between two organisms with only one obtaining the resource eg 2 fight for mate
• Parasitism 


  When one organism lives off another at its expense eg. Tick or tapeworm
• symbiosis

  when two organisms live together and at least one benefits
• example of symbiosis

  robin on tree
• human population dynamics

  war, disease, famine , contraception