How to use Quadrat to study distribution
- Place a 1m squared quadrat onto the ground at a random point wthin the first sample area. Divide the area into a grid and use a random number generator to pick the coordinates
- Count all the organisms within the quadrat.
- repeat steps above as many times as you can.
- Work out the mean number of organisms within the first sampl area
- Repeat steps 1-4 in the second sample area
- Finally compare the two means
How to use a transect
- Mark out a line in the area you want to study using a tape measure
- Collect data along the line
- Do this by just counting all the organisms youre interested in that touch the line
- Or collect data by using quadrats. Theses can be placed next to each other along th line or at intervasl for exapmle every 2m
Reliability & Validility
Make sure results are repeatable and reproducible
To make results more reliable:
- Take a large sample size. Bigger samples are more representative of the whole population
- use random samples randomly put down ormark out your quadrat/transect If all samles are in one spot and everywhere is different the results won't be reproducible
Must be reliabe and anser original question- need to control all the vriables.
Contol variables => know whether there is a difference in distribuion is caused by an environmental factor or not
Dont control variables=> wont know if a correlation has bee found because of chance the environmental factor or because of a different variable- study will not give valid data