Required Practical 10

Investigation into the effect of an environmental variable on the movement of an animal using either a choice chamber or a maze.

Describe how the effect of an environmental variable on the movement of an animal e.g, woodlice, can be investigated using a choice chamber

1. Set up choice chamber with different compartments to create different environmental conditions:

• e.g, humidity: add a drying agent to one side and damp filter paper to other.

• e.g, light: shine a light on one half and cover the other with black card.

2. Control other environmental conditions:

• e.g, if investigating humidity control light intensity with a lamp.

3. Use a teaspoon/forceps to place a set number of organisms on the centre of the mesh platform and cover with a lid.

4. After a specific amount of time, record the number of animals in each section.

5. Repeat after gently moving woodlice back to centre.

State why the woodlice are left alone for a set amount of time before their movement is recorded

They are left so:

1. They have time to establish the environmental conditions.

2. They are no longer affected by human handling/inteference.

Describe how you would ensure safe and ethical methods of handling

Safe - wear gloves, cover open wounds, and wash hands after handling to prevent the risk of infections.

Ethical - handle the organisms carefully and ensure they are returned to their habitat when necessary.

State how the effect of an environmental variable on the movement of an animal can be investigated using a maze

1. Change the environment at one end of the T shape e.g, add a food source.

2. Place the organism in the stem of the T.

3. Record whether the organism turns towards or away from the food source.

4. Repeat with a large number of the organism.

5. Clean maze between trials.

6. Repeat with food on the other side of the T.

Explain why the same organism is not used more than once

The same organism isn’t used more than once because it reduces stress on the organism and prevents the repetition of learned behaviours from the previous investigation.

Explain why a clean maze is used each time

A clean maze is used each time as previous atempts could leave the scent/trail of other organisms which could influence the behaviour of the current organism.

Explain which statistical test could be used to analyse the results

Chi-squared as:

• Data is categorical and can compare frequencies.

• To see if there is a significant difference between observed and expected results. Expected results would be an equal number of organism on each side.