ecosystems

• an ecosystem is a community of organisms and their physical environment interacting together
• ecosystems can be of any size but they’re usually places
• ecosystems contain abiotic and biotic factors
• abiotic factors are the non-living physical and chemical compounds of an ecosystem e.g:

  • rocks and minerals
  • oxygen
  • water
  • sunlight
  • temperature
• biotic factors are the living things, their remains and features associated with their activities and interrelationships
• a population is a group of individuals of the same species
• a community is all the different species that interact in an ecosystem
• a sustainable ecosystem is an ecosystem that is maintained over time and does not cause harm to the environment
• limiting factors prevent infinite population growth and are any factors which can restrict the size of a population
• tolerance range: the range of conditions within which a species can survive and reproduce
• limiting abiotic factors include:

  • light availability
  • water availability
  • nutrient availability
  • temperature
• interactions with other organisms influence a species success
• limiting biotic factors: competition, predation, mutualism, parasitism and commensalism
• competition: two individuals competing for the same resource
• predation: one individual feeds on another
• mutualism: two individuals benefitting from each other
• parasitism: one individual lives on and feeds on a host organism
• commensalism: one individual benefits and the other neither benefits nor is harmed
• carrying capacity is the maximum population size of a particle species that a given ecosystem can sustain
• the carrying capacity is set by the influences of all the biotic and abiotic factors over a long period of time
• sustainable populations live at or below their carrying capacity