Investigating Populations

You need to investigate populations of organisms

Investigating populations involves looking at abundance and distributions of a species in a certain area. 

Abundance - number of individuals of one species in a particular area, it's estimated by

• Counting the number of individuals in a sample. 
• Frequency - number of samples a species is recorded in (70% of samples)
• Percentage cover (just plants)  - how much of the area is covered by a species

Distribution - where a species is within the area

You need random samples

It would be too time consuming to measure each individual and it's distribution of every species in the entire area, so you take samples: 

• Choose an area  -  a small one within the area to be investigated 
• Samples should be random (avoids bias) 
• Use appropriate technique to take your sample (below)
• Repeat and take as many samples as possible, this gives you a more reliable estimate
• The number of individuals for the whole area can be estimated by taking an average of the data and multiply it for the whole area
• Percentage cover is worked out by taking an average of all samples

Different Methods Are Used To Investigate Different Organisms

Investigating…