Sampling

• it is impossible to count every single organisms in an area
• if you are interested in the distributed of an organism, or its population size, you need to take samples of the population.
• the abundance of a population is how many individuals you find in an area
• the distribution of an organisms is where the organisms is found
• sampling means taking an observation of a small area, which is representative of a larger area. you then scale up the sample to make estimates about the larger area.
• if you only take samples from one part of the area, you results will be biased. this mean that they are unlikely to give you an accurate representation of the whole area.
• to ensure that your sampling isn't biased, it need to be random
• this means that you need to use a method of choosing sample sites in which every site has an equal chance of being chosen.
• 1. Divide the field into a grid
  2. label the grid along the bottom and up the side with numbers or letters
  3. use a random letter generator to select coordinates
  4. take your sample at these coordinates
• another way of making sure that your sampling is unbiased is by using a systematic approach. In this case, you divide the area into sections of size s and choose a starting point at random. Then you move along the rows of squares systematically until you have counted enough plants.