10. Investigating Simple Animal Responses

Question 1

How can a choice chamber be used to measure the favourable environment of a small organism?

Answer 1

By setting up chambers in different quadrants with different environmental conditions: dark + dry, dark + damp, light + dry, light + damp

Organisms will move to the quadrant they find favourable

Question 2

What factors must be controlled when repeating the experiment?

Answer 2

Number of animals
Environmental conditions
Time allowed for animals to choose

Question 3

Which statistical test is used to analyse the results of this practical and why?

Answer 3

Chi squared test.

It compares the expected and observed values, and tests if there is a significant difference.

Question 4

What is the conclusion drawn if the calculated value is greater than the critical value?

Answer 4

Null hypothesis is rejected.
Less than 5% probability that the difference is due to chance alone.
There is a statistically significant difference between the expected and observed values.

Question 5

What do animals do when they are in unfavourable environments?

Answer 5

They move faster and change direction more frequently to increase their chances of survival.

Question 6

State the hazard and precaution involved in this practical.

Answer 6

The live organisms used are a biohazard.

Wash hands after handling.