Friday, 23 May 2014

Ecosystems

Ecosystems

  • Habitat - the place where an organism lives
  • Population - All the organisms of a species in a habitat
  • Community - All the different species in a habitat
  • Ecosystem - All the organisms living in a particular area and all the non-living conditions 

Quadrats

Quadrats can be used to find an estimate for the population size of a certain area.
  1. Place a 1m quadrat at a random point in the area that you're testing
  2. Count all the organisms within the quadrat
  3. Multiply the number of organisms by the total area of the habitat
NB - the placing of the quadrat must be random. To do this divide the area under investigation up into a grid and use a random number generator to find random coordinates. Place the quadrat there.

The sample may not be representative of the population as you're only testing a small section so to increase the accuracy (the value closest to the truth) do repeats to test a larger area.

Using Quadrats to find the Distribution of Organisms

You can investigate how the distribution of organisms change as you move from one area to another:
  1. Mark out a line in the area you want to study
  2. Collect data in metre intervals with the quadrats by placing them next to each other. 

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