Unit 3.2

Question 1

Give some examples of abiotic factors

Answer 1

1. Temperature
2. pH
3. Light intensity
4. Soil moisture

Question 2

Give some examples of biotic factors

Answer 2

1. Disease
2. Competition for resources
3. Food availability
4. Grazing
5. Predation

Question 3

What do you use to measure light intensity

Answer 3

Light meter

Question 4

What do you use to measure temperature

Answer 4

thermometer

Question 5

What do you use to measure soil moisture

Answer 5

moisture meter

Question 6

What do you use to measure pH

Answer 6

pH meter

Question 7

What errors can light meters have and how do you minimise them

Answer 7

• All of the light readings are similar
• Standing in the path of light, shades the meter and gives inaccurate readings
• So make sure you are not casting a shadow over the light meter when using it

Question 8

What errors can moisture meters/ pH meters have and how do you minimise them

Answer 8

• All of the results are similar
• Wipe the probes clean and dry between readings
• Make sure the probes are at the same depth each time

Question 9

What errors can thermometers have and how do you minimise them

Answer 9

• All the temperature readings are similar
• Give time to reach the correct reading

Question 10

How can plants and animals be sampled

Answer 10

1. Quadrats - sample plants and slow moving animals
2. Pitfall traps - sample small invertebrates

Question 11

What are indicator species

Answer 11

Indicator species are species that by their presence or absence indicate environmental quality/ levels of pollution

Question 12

How does predation affect biodiversity and the distribution of organisms

Answer 12

• A reduction in predators can lead to an increase in prey.
• An increase in prey can lead to an increase in predators
• A reduction in prey can lead to a reduction in predators

Question 13

What are the limitations and errors of quadrats and how can they be reduced

Answer 13

• Quadrats are not very accurate as they only sample a small section of land
• So you should repeat the experiment multiple times to ensure the results are reliable and representative

Question 14

What are the limitations and errors of pitfall traps and how can they be reduced

Answer 14

• Repeating the experiment multiple times to ensure you are getting reliable results
• Putting a cover over the top of the trap to prevent predators eating the trapped organisms and rain from getting in

Question 15

What are transect lines

Answer 15

• Transects are taking a line right across an area that you are sampling and counting the number of each species you find at regular intervals

Question 16

How does disease affect biodiversity

Answer 16

If a new disease appears it could cause many organisms to die through illness and could even wipe out an entire population. This would reduce the biodiversity of the ecosystem

Question 17

How does light intensity affect the distribution of organisms

Answer 17

A decrease in light intensity will reduce the rate at which plants photosynthesis