Quadrants paper2🩷

• Using Quadrats and Transects
• Quadrats


  Investigating distribution of small organisms that are slow-moving or don't move around by enclosing a known area in a square frame, e.g., 1 m²
• Ways to study the distribution of an organism

  • Measure how common an organism is in two or more sample areas
  • Study how the distribution changes across an area by placing quadrats along a transect
• Data collected from quadrats and transects provide quantitative information about the distribution of organisms
• Data collected can be used to provide evidence for environmental change


  If the distribution of organisms across an area changes over time, it could be due to changes in the environment
• Quadrats are squares used to study the distribution of small organisms that are slow-moving or stationary
• Ecologists are scientists who specialise in studying the interaction between organisms and their environment
• Before starting the experiment, check the area for hazards like broken glass and wash your hands after touching the soil
• Tip: it's really important
• Place a 1 m quadrat on the ground at a random point within the sample area. Divide the area into a grid and use a random number generator to pick coordinates
• Counting organisms within the quadrat

  Count all the organisms within the quadrat
• Calculating mean number of organisms per quadrat

  Work out the mean number of organisms per quadrat within the sample area
• When counting plants in your quadrat, make sure to count the number of actual plants and the number of flowers
• Anna's data


  • Quadrat 1: 18 daisies, Quadrat 2: 22 daisies, Quadrat 3: 20 daisies, Quadrat 4: 23 daisies, Quadrat 5: 23 daisies, Quadrat 6: 23 daisies, Quadrat 7: 25 daisies
• Comparing means


  Finally compare the two means. Eg you might find 2 daisies per m² in one area, and 22 daisies per m² in another area. You might want to find and compare the mode and median of your data too
• The mode is the number that appears most often in the data. For Anna's data above, the mode is 23 daisies per quadrat
• To find the median, you first need to put your data in numerical order. The median is the middle value in your data. For Anna's data, the median is 23 daisies per quadrat
• Estimating population size


  You can use quadrats to work out the population size of an organism in one area