Ecology and the environment

• What does the term environment mean

  Refers to all the physical feature of an area (e.g temp, soil ph)

  But can also include all the living creatures too
• what does the term population mean

  means all the organism of one particular species living in a particular area
• What does the term community mean?

  Means all the organisms of All the different species living in a particular area
• what does the term habitat mean

  An organism Habitat is where an organism lives. within an ecosystem there will be many different habitats
• what does an ecosystem mean

  it is an area where organisms interact with their physical environment

  • small- pond
  • large-forest
• what does is the term biodiversity

  It is the variety of life

  It looks at the number of different species in an area- the more species the more diverse an area will be
• what is the size of a quadrant

  0.5m x 0.5 = 0.25msq
• why do we use quadrats

  to avoid human bias.
• what is the method of using a Quadrat

  1. Select two areas of a field which have a different plant community
  2. In the first area lay out 2 x 10m tape measures to form sides of a square
  3. Use a table of random numbers to find the numbers you can use a coordinates to position the quadrat
  4. Count the number of each plant species in the quadrat
  5. Repeat for 9 more quadrats
  6. Repeat this for the 2nd area
• what are abiotic factors that affect communities

  • environmental conditions- temperatures, light intensity, soil pH
  • toxic chemicals- chemical pesticides and fertilisers
• what are biotic factors

  • availability of food
  • number of predators- a reduction in predators can lead to an increase in prey. this leads to overgrazing which can reduce biodiversity
  • competition
• what are producers, consumers and decomposers

  • producers-plants which can photosynthesis to produce thier own food
  • consumers- eat plants or other animals
  • decomposers- bacteria, fungi which break down material
• What are the different trophic levels

  Level 1- producer

  Level - herbivore/ primary consumer

  Level 3- omnivore/ secondary consumer

  Level 4- omnivore

  Level 5- carnivore/ quaternary
• what is a food chain

  it is when food passes from plants to animals in a chain

  • the arrow in the food cha in is the direction of energy flow
  • the stages in a food chain are called trophic levels
• Chain of animals and plant 


  Foood chain

  
• what is a food Webb?

  it is when consumers rarely depend on only one type of food and often a particular foood is eaten by more than one consumer. this means food chains are interconnected.
• what are period of number

  it is the number of individuals counted in a food chain which is constructed into a pyramid
• what are pyramids of biomass

  the block of each living at each level. the total biomass of each level

  
• what are pyramids 0of energy

  they show the amount of energy at each trophic level
• Why is only 10% of energy transferred from one trophic level to the next

  • some parts are not always eaten (rots or bones)
  • Some is not digested and passes out as faeyes
  • Energy is released during respiration which cannot be passed on
  • Energy is lost through heat or movement
  • Energy not eaten or in faeces goes to decomposers
• transfer of energy

  • solar energy is converted by photosynthesis into chemical energy by the plants
  • this chemical energy is used by the primary consumers to make its own body tissues which will then be passed onto the secondary conSumer when it eats the primary consumer
  • the energy is released by respiration in all animals
• What process 'fixes' carbon atoms from carbon dioxide?

  Photosynthesis
• What do decomposers do to dead organisms?

  They feed on them and break down carbohydrates
• What is glucose used for by decomposers?

  To respire and release carbon dioxide
• How are carbon atoms passed along food chains?

  Through feeding and assimilation
• What does respiration produce from organic compounds?

  Inorganic carbon dioxide
• What happens to carbohydrates during respiration?

  They are broken down to release energy
• What releases carbon dioxide into the atmosphere?

  Combustion of fossil fuels
• What are the stages of the carbon cycle?

  1. Photosynthesis: Fixation of carbon from CO2
  2. Decomposition: Breakdown of organic matter by decomposers
  3. Respiration: Release of CO2 from organic compounds
  4. Feeding: Transfer of carbon through food chains
  5. Combustion: Release of CO2 from burning fossil fuels
• What is the carbon cycle

  Where carbon is used and released

  
• What is the nitrogen cycle?

  A series of processes converting nitrogen forms
• Why is nitrogen required by living organisms?

  To make proteins
• Why can't plants and animals absorb nitrogen directly from the air?

  N2 gas is stable and hard to break down
• What are the two ways nitrogen gas can be converted into a usable form?

  1. Nitrogen-fixing bacteria convert N2 to ammonium compounds
  2. Lightning splits N2 into nitrous oxides that dissolve in rainwater
• What do nitrogen-fixing bacteria convert nitrogen gas into?

  Ammonium compounds
• Where can nitrogen-fixing bacteria live?

  In soil or root nodules of plants
• How does lightning contribute to the nitrogen cycle?

  It splits N2 into nitrous oxides
• In what form do plants absorb nitrogen from the soil?

  As nitrates
• How do animals obtain nitrogen?

  By eating plant proteins
• What happens to nitrogen as it moves up the food chain?

  It is passed from primary to secondary consumers