Habituation (14+15)

Question 1

What is habituation?

Answer 1

The reduced response to an unimportant stimulus after repeated exposure over time

Question 2

Why does habituation occur?

Answer 2

• means animals don’t waste energy

- can spend more time doing activities for their survival such as feeding

Question 3

When investigating habituation what would the method be?

Answer 3

• get a snail
• allow it to adjust to the environment before starting the investigation
• tap the snail between it’s tentacles
• record how long it takes for it’s tentacles to fully extend after being stimulated
• ensure the strength of the stimulus is maintained
• repeat the stimulus
• repeat full experiment after time delay or with a different snail

Question 4

When investigating habituation what are the variables to be controlled?

Answer 4

• temperature
• background noise
• humidity
• species, age gender of snail
• previous handling of the snail

Question 5

When investigating habituation what is the dependent variable?

Answer 5

The number of repetitions of the stimulus, how many times the sail has been poked.

Question 6

When investigating habituation what is the dependent variable?

Answer 6

The amount of time it takes for a snail to fully extend it’s tentacles after stimulation, being poked on the head.

Question 7

Describe the biological process of habituation.

Answer 7

• repeated exposure to a stimulus decreases the amount of calcium ions that enter the presynaptic neurone
• this decreases the infulx of calcium ions means less neurotransmitters are released from the vesicle into the synaptic cleft
• fewer neurotransmitters bind to receptors in the postsynaptic membrane
• fewer sodium ion channels in the postsynaptic membrane open so there is a reduced chance of the threshold for an action potential to be reached
• depolarisation is unlikely to occur