Ecosystems

Defining ecosystems

• Ecosystems are made of all living organisms that interact with each other in a defined area plus the physical factors present in the region
• The boundaries of an ecosystem are defined by the person or team carrying out the study

Factors affecting ecosystems

• Biotic factors = living factors
  • competition for food, space and breeding partners
• Abiotic factors = non-living factors
  • Light --> plants develop strategies to deal withe different light intensities such as large leaves in areas with low intensity or reproductive systems that only operate if there is optimum light intensity
  • Temperature --> greatest effect is on the enzymes of the organism --> changes to the temperature can cause migration or hibernation, leaf fall, dormancy or flowering
  • Water --> a lack of water usually leads to water stress and/or death --> xerophytes and camels are adapted
  • Oxygen availability --> in aquatic conditions its beneficial to have fast-flowing water as it has high concentrations of oxygen, in waterlogged soil the air spaces between soil particles are filled with water so reduces the oxygen available to the plants
  • Edaphic (soil) factors 
    • clay soil is easily waterlogged and forms clumps when wet
    • loam soil retains water but doesn't become waterlogged
    • sandy soil is free draining so doesn't retain water and is easily eroded