B2.4 Organisms and their environment

Question 1

Suggest three (out of a possible 5) reasons for the distribution of living organisms in a particular habitat

Answer 1

• Temperature
• Nutrients
• Amount of light
• Availability of water
• Availability of oxygen and carbon dioxide

Question 2

Explain how temperature affect the distribution of living organisms in the Arctic (3 marks)

Answer 2

• Arctic plants are small because temperature is a limiting factor of photosynthesis
• Less herbivores can survive because there is less food

Question 3

How does light affect the distribution of living organisms?

Answer 3

Many animal and plant species’ breeding patterns are linked to day length (light intensity)

Question 4

In what environment does the availability of oxygen affect organisms and in what way?

Answer 4

Water/Aquatic areas

Most fish need a high level of dissolved oxygen

Question 5

What does a limited amount of carbon dioxide affect?

Answer 5

Plants; they are more vulnerable to insect attacks

Photosynthesis—->plant growth

Question 6

What is quantitative data?

Answer 6

Data measured by the quantity of something not the quality

Question 7

How would you obtain quantitative data on the distribution of organisms?

Answer 7

• Random sampling with quadrats

- Sampling along a transect

Question 8

State 3 ways to obtain valid data from using a transect and quadrat

Answer 8

• Place the quadrat at regular intervals
• Repeat at least three times
• Score the presence of each species