4.3 describe the use of quadrats as a technique for sampling the distribution of organisms in their habitats.

Quadrat technique used to sample the pop of species.

Sample: Random (Bias)
             Representative (Large) 
How they organize: Grid system. This enables you to identity all material - Works like a graph using coordinates. The guadrats are placed in the grid in individual squares - for placement  for "Bias" sampling, you use "random" numbers and they are generated along the "x" & "y" axis.

Representative sampling : A small quantity of materials, whose characteristics represent (as accurately as possible) the entire batch,population.