14. Ecosystems

• What is a community

  All of organisms of all species living in an ecosystem
• What is a population

  A group of organisms of the same species
• What is interspecific competition?

  between different species
• What is intraspecific competition

  Between the same species
• What is carrying capacity

  The maximum size that a population can remain sustainable in a habitat
• What is energy eventually lost as

  Heat
• What are autotrophs

  Primary producers
• Why does a food chain only have up to 5 or six levels

  All energy is lost
• Why isn’t all light energy used for photosynthesis

  Doesn’t all hit the plant

  might not be correct wavelength
• What is biomass

  Mass of organic material in an organism
• Why do we have to measure dry biomass

  Amount of water varies over time
• What is a bomb calorimeter

  Used to find the chemical energy store in food (calories)
• How do bomb calorimeters work

  Dry material is burnt in oxygen, the energy given off heats up the water, the rise in temp can be used to calculate the energy
• What is NPP

  GPP - R
• What is GPP

  Chemical energy store in plant biomass
• Why is energy lost between transfers

  not all is digested - lost in faeces

  not all animal is eaten

  heat
• How do we calculate net production

  N = I - (F + R)

  I = ingested food

  F = faeces

  R= respiration
• How can farmers increase efficiency of energy transfers

  Restrict movement - less heat loss

  fed on a concentrated diet

  Genetically selected for high productivity
• What is succession

  The way in which the different species of organisms which make up a community change over a period of time
• What are the main events of succession

  A hostile environment is colonised by pioneer species. The abiotic environment of the habitat is changed. The environment becomes more suitable to support different species. Establishment of new species increases the species diversity as various groups of animals and the habitat. The early colonisers are outcompeted the changes in the abiotic factors result in a less hostile environment and increasing biodiversity. a climax community develops