Sampling Techniques

Scientists spend a large amount of time studying the environment.

To do this they need to understand the techniques required.

Scientists usually want to knowWhere an organism is found

(distribution)The number of that organism present

(population)

It is usually not possible to look at the entire environment in detail.

Therefore, a small portion or a section of the area is sampled.

Sampling small sections gives us a representative picture of the whole area.

Here are a few techniqueshttp://cleo.skoool.co.uk/content/

keystage3/biology/pc/learningsteps/SATLC/LO_Template.swf

Quadrats are square frames of a known size e.g. 0.25m2. They are used to sample all the plant species in a particular area. Pitfall traps are used to catch small, crawling insects. They can be set up and left overnight to catch nocturnal species.

A pooter is used to catch small insects. A breath is taken in through the mouthpiece which has a piece of net covering the end. The insects are sucked in to the holding chamber.

Sweep nets are used in long grass to catch organism. They can also be used in ponds.

The Tullgren funnel removes living organisms from leaf litter. The organisms move away from the heat and the light to prevent drying out.