Requierd Practical 9

Question 1

What is a Quadrat used for ?

Answer 1

Quadrats are used to estimate the number of individuals % cover of a species in an area in order to compère with another area. This allows us to see if a abiotic factor effects the distribution of a species.

A Quadrat is a square frame enclosing a known area.

Question 2

What is the first section of the method for using a Quadrat ?

Answer 2

1 place a (1m2) Quadrat on the ground at a random point within the first sample area.

E.g. Devide the are into a grid and use a random number generator to pick coordinates.

2 count all the selected organisms within the Quadrat

3 repeat steps 1 and 2

Question 3

How do you work out the mean number of organisms per Quadrat within the sample area?

Answer 3

Mean = total number of organisms -:- Number of quadrants

E.g.
Anna counted the number of daisies in 7 quadrats with her first sample area and recorded the following results:
18,20,22,23,23,23,25
Mean = 154 (total number of daisies ) -:- 7 ( number of quadrats )
Mean = 22 dasies per Quadrat

Question 4

How do you work out the mode ?

Answer 4

The mode is the most common value

In my example the mode is 23

Question 5

How do you work out the median ?

Answer 5

The median is the middle value, when they are in order of size

In y example it is 23

Question 6

What do you do once you have looked at the first sample area with a Quadrat ?

Answer 6

Repeat steps 1 to 4 in a second area

Comparative the to means