Adaptations, interdependence and competitors

• community


  • made up of the populations of different species
• ecosystem


  community interacts with abiotic (non-living) parts of the environment
• species in a community

  • interdependent
  • adapted to conditions of environment
• interdependence 


  • organisms in a community depend on other organisms for services
  • remove or add species to community, affect populations of prey and predators
• examples of services in interdependence

  • animals eat animals and plants
  • plants produce food by photosynthesis
  • animals use material to build shelter
• competition


  • animals and plants compete within in a species or with different species for resources
• stable community 


  all the species and environmental factors are in balance, population sizes remain constant
• why do organisms require materials?

  survive and reproduce
• abiotic factors affecting communities

  • light intensity
  • temperature
  • moisture levels
  • soil pH and mineral content
  • availability of water/carbon dioxide
  • wind intensity and direction
• light intensity

  • affects distribution of animals and plants
  • light limits photosynthesis
• temperature

  • limiting factor on photosynthesis and growth of plants
• moisture levels

  • animals and plants need water to survive
  • no water = little or no life
• soil pH and mineral content

  • soil pH affects rate of decay, effects release of mineral ions back into the soil
  • plants struggle to grow in areas with low levels of mineral ions
• availability of oxygen

  • impacts aquatic animals
  • oxygen levels vary in water
• availability of carbon dioxide

  • limiting factor of photosynthesis and plant growth
  • affects distribution of organisms
• biotic factors affecting communities

  • food availability
  • new predators
  • new pathogens
  • interspecific competition
• food availability

  • more food, organisms breed successfully
• new predators

  • organisms with no defences may be quickly wiped out
• new pathogens

  • population has no resistance to it, damaged and wiped out
• interspecific competition

  • new species may outcompete another as it’s better adapted to environment
  • numbers become too low for successful breeding
• habitat


  the environment in which an organism lives
• population


  total number of organisms of the same species living in the same geographical area
• what do plants compete for?

  • light
  • space
  • water
  • mineral ions
• what do animals compete for?

  • food
  • water
  • mating partners
  • territory
• animal adaptations

  • structural
  • behavioural
  • functional
• functional adaptations

  body functions of an organism e.g. reproduction, metabolism
• structural adaptations


  shape and colour of an organism
• behavioural adaptations


  the way an organism behaves e.g. external stimulus to survive
• adaptation


  living organisms have special features for survival
• plant adaptations

  • changing surface area
  • collection of water
  • storage of water