4.2 practical: investigate the population size of an organism in two different areas using quadrats

Quadrat: square frame enclosing a known area, such as 1 meter squared

To study population size of a species:
1. Place a 1-meter squared quadrat on the ground at a random point in the sample area. This is done by dividing the sample area into a grid and using a random number generator to pick the coordinates to place your quadrats at.

2. Count all the organisms you're interested in within a quadrat.

3. Repeat steps 1 and 2 at least 3 times.

4. Find the mean (average) of the number of organisms within the sample area.

5. Calculate the population size. Population size is essentially the mean number of organisms per meter squared, so just multiply the mean number of organisms from step 4 and multiply this by total area of habitat.

To study/compare population size in 2 sample areas:
1. Place a 1-meter squared quadrat on the ground at a random point in the sample area. This is done by dividing the sample area into a grid and using a random number generator to pick the coordinates to place your quadrats at.

2. Count all the organisms you're interested in within a quadrat.

3. Repeat steps 1 and 2 at least 3 times.

4. Find the mean (average) of the number of organisms

5. Repeat steps 1 and 4 in the SECOND sample area, and take mean.

6. Compare 2 means.