Required Practical 10: Investigating Animal Responses Using a Choice Chamber or Maze
Laura Armstrong & Joe Wolfensohn
Teachers
Contents
Recall Questions
This topic requires prior knowledge of taxes and kineses. You can test your knowledge on these below.
What is a taxis?
A directional movement response of a motile organism toward or away from a stimulus.
What is a kinesis?
A non-directional / random movement response where the rate of movement depends on the intensity of the stimulus.
A small beetle moves away from a light source, what type of response is this?
Negative Phototaxis
Topic Explainer Video
Check out this @JoeDoesBiology video that explains required practical 10 or read the full notes below. Once you've gone through the whole note, try out the practice questions!
Background & The Choice Chamber
Taxis and Kinesis
Animals respond to external stimuli to maintain favourable environmental conditions:
- Taxis: Directional response (e.g., woodlice move away from light = negative phototaxis).
- Kinesis: Change in speed or turning rate, not direction (e.g., woodlice move more in dry areas, then slow down in humid areas).
These behaviours help increase survival in changing environments.
The Choice Chamber: Design and Function
What is a Choice Chamber?
A device used to expose animals (e.g., woodlice, maggots) to multiple environmental conditions to observe behavioural preferences.
Core Investigation
Aim:
To investigate how animals respond to different environmental stimuli (e.g., light, humidity, temperature) using a choice chamber.
Example Experimental Setup
Organism:
Woodlice (commonly used as they show clear kinesis in response to humidity and light).
Stimuli:
- Light vs. Dark (phototaxis).
- Dry vs. Moist (hydrokinesis).
Equipment:
- Choice chamber with 2 or 4 quadrants.
- Damp paper towel (moist quadrant).
- Dry paper towel with desiccant (dry quadrant).
- Lid with mesh to prevent escape.
- Stopwatch.
- Light source (optional, for phototaxis).
Methods of Taxis and Kinesis
Kinesis: Humidity
- Line half of the chamber with moist paper and half with dry paper + desiccant (to remove moisture).
- Place 10 woodlice in the centre.
- Cover chamber to avoid external light (unless testing light).
- Observe and record number of woodlice in each quadrant every 30 seconds for 10 minutes.
- Repeat multiple times to increase reliability.
Taxis: Light
- Use half of the chamber under direct light, and cover the other half with foil for darkness.
- Follow the same steps as above, but vary only the light exposure.
Data Collection & Analysis
- Use a tally chart to record the number of animals in each quadrant.
- Plot a bar chart of mean number of woodlice per condition after 10 minutes.
- Use a chi-squared test to determine if the distribution differs significantly from random distribution (we would expect an even distribution of woodlice in each quadrant but may observe something different).
Additional Extension: Maze Investigation
Alternative Design:
- A simple maze with different environments (e.g., light at one end, darkness at the other).
- Track speed and choice of path to determine behavioural preferences.
Use Case:
- Best for testing directional movement (taxis).
- Can be used with maggots, mealworms, or woodlice.
Key Variables
Key Terms
- Taxis: Directional movement response (towards or away).
- Kinesis: Non-directional movement response based on stimulus intensity.
- Choice chamber: Apparatus used to test organism behavior in different environments.
No answer provided.
Exam Tips
Clearly distinguish between taxis (directional) and kinesis (non-directional) in your analysis and conclusion.
There will be lots of variance and uncertainty so a statistical test should be used to determine the significance of the difference between observed and expected results.
No answer provided.
Describe how you would investigate the effect of humidity on the behaviour of woodlice. (4 marks)
- Set up a choice chamber with one side containing damp paper (humid) and one with desiccant (dry).
- Place an equal number of woodlice in the centre and allow them to move freely.
- Record the number in each quadrant every 30 seconds for 10 minutes.
- Repeat and calculate means to identify a pattern, e.g., preference for humid conditions.
- Use a chi-squared test to determine if the distribution differs significantly from random distribution.
Practice Question
Try to answer the practice question from the TikTok on your own, then watch the video to see how well you did!