B2.4 Organisms and their environment

Question 1

How can quantitative data on the distribution of organisms be obtained by?

Answer 1

random sampling with quadrats.

sampling along a transect

Question 2

What can you use to gather information on how a distribution of organisms changes within an area? describe how you would so so

Answer 2

A TRANSECT

mark out a line in the area you want to study using a tape measure. collect data along the line. You can do this by counting all the organisms you are interested in that touch the line or collect data by using quadrats by placing them next to each other along the line or at intervals

Question 3

How can you measure how common an organism is in 2 sample areas?

Answer 3

Place the quadrat at a random point at the first sample area. Count all the organisms within the quadrat. Repeat steps 1 and 2 as many times as you can. Work out the mean number of organisms per quadrat in the first sample area. Repeat steps 1 to 4 in the second sample area. Compare the 2 means.

Question 4

What are 5 physical factors that may affect organisms?

Answer 4

temperature, availability of nutrients, mount of light, availability of water, availability of oxygen and carbon dioxide

Question 5

How can you make your results more reliable?

Answer 5

Take a larger sample size

Question 6

What does it mean if your results are reliable?

Answer 6

They are repeatable and reproducible

Question 7

What does it mean if your results are valid?

Answer 7

They are reliable (repeatable and reproducible) and also answer the original question

Question 8

How can you improve the validity of collecting results using a transect?

Answer 8

repeat several times elsewhere in the area