4.3 Explain how quadrats can be used to sample the distribution of organisms in their habitats

A randomly placed quadrat is taken and the number of a population in a square is taken. This can be

repeated in different areas and compared to see how densely an organism has populated their habitat.

The more data that you are able to collect, the more reliable the results will be. This minimizes the risk of 

results being contaminated by unequal/unusual distribution 

4.2 Explain how quadrats can be used to estimate the population size of an organism in two different areas

The quadrat is placed in the area and the number of organisms in the quadrat is counted. This can be

repeated (averaged) and then multiplied to the total area of the land to find an estimation of the

population size.

Exam question:

Suggest a method that could be used to estimate the population of fire ants in an area (4 marks)

* Use a quadrat

* Count the number of ants found in the area of the quadrat

* For an estimation, multiply that number by the size of the area

* Repeat by throwing quadrat at random in different places in the area