Ecosystem

• ecosystem

  interaction of a community of living organisms and non-living factors of their environment
• competition

  occurs between different species affecting population sizes
• what do they compete for

  light, space, food, mates, territory
• what happens to less competitive species

  move to another area

  adapt new survival strategies

  become extinct in that area
• species

  organisms that can interbreed to produce fertile offspring
• habitat 


  the place where an organism lives
• population

  all the members of the same species within a habitat
• community

  all the different populations within the same habitat
• interdependence

  each species depend on each other
• stable community

  all the species and the environment factors are in balance so that population sizes remain fairly constant
• producer

  plants or algae which photosynthesise to produce biomass for the rest
• consumer

  all animals above the producer
• decomposers

  bacteria or fungi which break down dead organisms

  release enzymes onto the dead matter the consume the broken down substances

  plants absorb the decomposed nutrients through its roots
• abiotic are non-living 


  light intensity

  temperature

  carbon dioxide levels

  oxygen level

  soil pH and mineral content
• biotic are living

  new predator arriving

  competition

  new pathogens

  availability of food
• what is the water cycle

  provides fresh water for plants and animals on land before draining into the seas. Water is continuously evaporated and precipitated

  
• what is meant by the carbon cycle

  living things are made up of things they take from the world around them which is then passed up the food chain or returned to the environment

  
• what is responsible for decomposition

  microorganisms (bacteria/fungi)
• four limiting factors for decay

  temp - faster enzyme activity

  oxygen - many respire aerobically to survive

  water - faster in moist environments

  number of organisms - more microorganisms
• what is biogas decay

  sludge waste digested anaerobically to be burned as fuel biogas generators must be kept at a constant temp can’t be stored as a liquid
• what is global warming

  Gases in the atmosphere naturally act as an insulating layer, absorbing

  most of the energy that would normally be radiates out into space.

  This increases the temperature of Earth. If this didn't happen earth would be cold at night with nothing holding in the temp.

  The gases are called greenhouse gases, and increasing amounts of them means the earth gets increasingly warmer.
• what problem can global warming cause

  increase in temp seawater to expand and ice melts

  distribution of animals to change

  change in migration patterns

  biodiversity reduces
• Trophic levels

  the different stages of a food chain consisting of one or more organisms with a specific role
• tropic level 1

  producers - make there own food by photosynthesis
• Tropic level 2

  primary consumers - herbivores only eat plants and algae
• Trophic level 3

  secondary consumers - carnivores meat eaters
• Trophic level 4

  tertiary consumers - apex predators
• food security

  having enough food to feed a population
• causes of food insecurity

  population increase

  new pathogens in crops (famine)

  high input cost (too expensive)
• how are animals kept to make food production more efficient

  Limiting movement and keeping them in a temperature controlled environment can maximise energy used for growth. Protein rich food also maximises growth -increased food produced.