B2.4 Organisms and their environment

Question 1

What physical factors may affect an organism?

Answer 1

Temperature, availability of nutrients, amount of light, availability of water and availability of oxygen and carbon dioxide

Question 2

What is a quadrat?

Answer 2

A square frame enclosing a known area e.g. 1m squared

Question 3

What is the first step for collecting a random sample with a quadrat?

Answer 3

Place a quadrat on the ground at a random point within the first sample area. You could divide the area into a grid and use a random number generator to pick which square you place it in

Question 4

How do you work out population size?

Answer 4

You work out the mean number of the organism in one quadrat then times it by the total area to get the population of the entire sample area

Question 5

What is the first step for collecting a random sample with a transect line?

Answer 5

Mark out a line in the area you want to study using a tape measure

Question 6

How do you make your results more reliable?

Answer 6

Take a large sample size, use random samples

Question 7

How do you make your results valid?

Answer 7

Control all the variables, this way you can see whether it is an environmental factor affecting distribution

Question 8

What is the second step for collecting a random sample with a quadrat?

Answer 8

Count all the organisms within the quadrat

Question 9

What is the third step for collecting a random sample with a quadrat?

Answer 9

Repeat steps 1 and 2 as many times as possible

Question 10

What is the fourth step for collecting a random sample with a quadrat?

Answer 10

Work out the mean number of organisms per quadrat within the first sample area

Question 11

What is the fifth step for collecting a random sample with a quadrat?

Answer 11

Then repeat steps 1-4 in a different sample area

Question 12

What is the sixth step for collecting a random sample with a quadrat?

Answer 12

Then compare the data of the two different areas

Question 13

What is the second step for collecting a random sample with a transect line?

Answer 13

Collect data along the line. This is done by counting the number of the organisms you are interested in that touch the line

Question 14

What is the third step for collecting a random sample with a transect line?

Answer 14

Or you could use quadrats, placing them next to each other along the line at intervals