ecology

• define population

  A species that occupy the same habitat
• define habitat

  The place in which an organism lives
• define community

  populations of different species interacting
• define biodiversity

  The variety of plant and animal species in an ecosystem
• Describe how a quadrat can be used to investigate the population size of an organism in two different areas.

  Divide the sample area into a grid - Place a quadrat randomly using a random number generator - count how many of the species is present - repeat these steps to calculate a mean - do the same procedure to the second sample area
• How can the reliability of quadrat sampling results be improved?

  Randomly place the quadrat - Use the same sized quadrat each time
• What are biotic factors?

  Biological living factors
• What are abiotic factors?

  Non biological (non living) factors
• define producer

  organisms which produce their own food using photosynthesis
• define consumer

  organism which eat plants and other animals
• what is a decomposer

  organisms which decay dead material to help recycle nutrients
• what is trophic level?

  the position in a food chain or food web
• what is meant by a food chain or food web

  Shows feeding relationships by showing which organism eats which organism and shows the flow of energy from producer to top consumer through trophic levels
• How does chemical energy flow through food chains and webs

  by feeding
• What is a pyramid of numbers?

  They represent the number of organisms at each trophic level, irrespective of their biomass
• What is a biomass?

  The total amount of living material in a organism
• What is a pyramid of biomass?

  They represent the total mass of organisms in each trophic level, irrespective of their number.
• explain why only 10% of energy is transferred from one trophic level to the next?

  energy is lost through

  • Egestion (removal of faeces)
  • Excretion (removal of waste products)
  • respiration
  • Some food parts are indigestible
  • Not all parts of the organism is eaten
• Describe the process of the carbon cycle

  • Carbon dioxide is absorbed by green plants in photosynthesis
  • Carbon is used to make glucose and proteins
  • Plants respire releasing carbon dioxide
  • Plants and animals die and are decomposed by microorganisms
  • Microorganisms respire, releasing carbon dioxide
  • Complete combustion of fossil fuels releases carbon dioxide.
• what effect dies acid rain have?

  • Destroys limestone buildings
  • Kills trees
  • Makes ponds too acidic leading too death of fish
• what produces carbon monoxide?

  • Incomplete combustion of fossil fuels
• What effect does carbon monoxide have on the body?

  • It binds irreversibly to haemoglobin so less oxygen is transported