OxfordAQA International GCSE Biology: Nervous system, reflexes and animal behaviour (9201) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions are aligned to the OxfordAQA International GCSE Biology (9201) specification, Version 5.2, for exams May/June 2018 onwards, sections 3.4.1 and 3.4.6. The qualification is untiered. Revise first with the study guide or revision notes. See also the OxfordAQA IGCSE Biology hub and the checklist.

Questions

1. The nervous system lets humans react to their surroundings.

(a) Name the two parts of the central nervous system (CNS). [1] (b) Which type of neurone takes impulses from a receptor into the CNS? [1] (c) State what is released at a synapse. [1] (d) State how a gland responds when it receives impulses. [1]

2. A girl treads on a sharp pin with her bare foot and pulls her foot away at once. Describe the pathway in the nervous system that produces this reflex action, from the receptor to the response. [5]

3. A cyclist hears a car horn behind her and swerves to the side. Copy and complete the table to analyse the behaviour. [5]

Stage	Answer
Stimulus
Receptor
Coordinator
Effector
Response

4. Impulses travel along a reflex pathway of total length 0.9 m at a speed of 45 m/s. Ignore the delay at synapses.

(a) Calculate the time taken for impulses to travel along the pathway. Give your answer in seconds. [2] (b) Explain why a reflex action is quicker than a decision to move that is made consciously. [2]

5. Male birds of many species sing and display to females before mating.

(a) Explain how courtship behaviour can help a female to choose a mate. [2] (b) State two of the four mating strategies named in the specification. [2]

6. In a species of fish, a parent guards the nest. Researchers compared 50 eggs with a guarding parent and 50 eggs where the parent had been removed. After hatching, 35 young survived in the guarded nest and 4 survived in the unguarded nest.

(a) Calculate the percentage of young that survived in each nest. [2] (b) Use the data to explain why parental care can be a successful evolutionary strategy. [2] (c) Describe two risks to a parent that guards a nest. [2]

7. Name the type of behaviour shown in each example. [5]

(a) A newly hatched spider spins a web without ever having seen one. (b) Ducklings follow the first large moving object they see after hatching. (c) Sheep in a field stop running away from a passing train after a few weeks. (d) A cat runs to the kitchen when it hears a can opener, which has always been used before it is fed. (e) A pigeon learns to peck a lever because a pellet of food follows.

8. A hermit crab withdraws into its shell when a shadow passes over it. A shadow was passed over the crab in five blocks of 10 passes. The number of withdrawals in each block is shown.

Block	1	2	3	4	5
Withdrawals	9	7	5	2	1

(a) Describe the trend in the results. [2] (b) Calculate the percentage decrease in withdrawals from block 1 to block 5. Give your answer to one decimal place. [2] (c) Name this type of learning and give one advantage of it to the crab. [2]

9. A trainer sounds a bell before giving food to 20 puppies. After a number of pairings, the bell is sounded alone and the trainer counts how many puppies salivate.

Number of pairings	5	10	15	20
Puppies salivating	3	9	16	18

(a) Name the neutral stimulus and the stimulus that naturally causes salivation. [2] (b) Calculate the percentage of puppies that salivated at the bell alone after 15 pairings. [1] (c) Explain the trend in the results. [2] (d) State one difference between this type of learning and operant conditioning. [2]

10. Humans use conditioning to train animals.

(a) Describe how a sniffer dog can be trained to detect a particular scent. [3] (b) Police horses must stay calm near crowds and flags. Describe how a horse can be trained to do this. [3] (c) Before training a dog found 14 of 20 hidden samples. After training it found 18 of 20. Calculate the increase in the percentage of samples found. [2]

11. Animals communicate using signals.

(a) Give one example each of a sound signal, a chemical signal and a visual signal. [3] (b) Suggest why an alarm call is more useful than a chemical signal for warning others of a predator that is attacking now. [2]

12. A pair of birds stays together for one breeding season. The male sings and displays at the start. Both parents feed their chicks. A parent that leaves the nest to feed can be caught by a predator. When the chicks hatch they follow the first moving object they see. When a loud noise was first played near the nest the birds hid, but after repeated noises with nothing harmful happening, they ignored it.

(a) Explain what the male’s singing and display advertise to the female. [2] (b) Name the mating strategy shown by the pair. [1] (c) Give two risks of parental care shown or suggested in the information. [2] (d) Name the behaviour shown by the chicks and explain how it helps them survive. [2] (e) Name the behaviour shown by the birds towards the repeated noise and explain why it is useful. [2]

Answers

1. (a) The brain and the spinal cord [1]. (b) A sensory neurone [1]. (c) A chemical [1]. (d) It releases (secretes) a chemical substance [1]. [4] Examiner insight: Name structures exactly: “the spine” is too vague for the CNS.

2. A pain receptor in the skin of the foot detects the pin [1]. Impulses pass along a sensory neurone to the CNS [1]. At a synapse a chemical is released that causes an impulse along a relay neurone [1]. A chemical is released at the next synapse, causing impulses along a motor neurone to the effector [1]. The effector, a muscle in the leg, contracts and pulls the foot away [1]. [5] Examiner insight: Give the neurones in order and mention each synapse and the chemical that crosses it.

3. Stimulus: the sound of the horn [1]. Receptor: sound receptors in the ear [1]. Coordinator: the CNS (brain) [1]. Effector: muscles in the arms (or body) [1]. Response: the muscles contract and the cyclist swerves [1]. [5] Examiner insight: Each row needs a specific answer: “the body” is not an effector, and the stimulus is the sound, not the ear.

4. (a) time = distance / speed = 0.9 / 45 [1] = 0.020 s [1]. (b) The reflex is automatic, so there is no delay while the brain makes a conscious decision [1]. The pathway is short, with few synapses [1]. [4] Examiner insight: Show the equation, the substitution and the unit.

5. (a) The display advertises the quality of the male, for example that he is healthy or strong [1]. The female can then choose a mate whose genes are likely to give offspring a better chance of survival [1]. (b) Any two from: a mate for life; several mates over a lifetime; a mate for a breeding season; several mates over one breeding season [1] [1]. [4] Examiner insight: “Attract a mate” alone only describes; link the display to quality.

6. (a) Guarded: 35 / 50 x 100 = 70 % [1]. Unguarded: 4 / 50 x 100 = 8 % [1]. (b) Many more young survive when a parent guards them (70 % compared with 8 %) [1]. More young reach adulthood and breed, so more of the parent’s genes are passed on [1]. (c) Any two from: the parent may be attacked or killed by a predator while defending the nest; it may not be able to feed, using up energy reserves; it may be more visible to predators [1] [1]. [6] Examiner insight: In a “use the data” question, quote both percentages, then link to genes.

7. (a) Innate [1]. (b) Imprinting [1]. (c) Habituation [1]. (d) Classical conditioning [1]. (e) Operant conditioning [1]. [5] Examiner insight: “Classic” and “classical” conditioning mean the same, but do not write just “conditioning” when two types are possible.

8. (a) The number of withdrawals decreases [1] from 9 in block 1 to 1 in block 5, with the largest fall between blocks 3 and 4 [1]. (b) (9 - 1) / 9 x 100 [1] = 88.9 % [1]. (c) Habituation [1]. The crab does not waste energy hiding from a harmless stimulus, so it can keep feeding [1]. [6] Examiner insight: Quote figures from the table and follow the decimal places asked for.

9. (a) Neutral stimulus: the bell [1]. Stimulus that naturally causes salivation: the food [1]. (b) 16 / 20 x 100 = 80 % [1]. (c) As the number of pairings increases, more puppies salivate to the bell alone [1] because they have learned to link the bell with food [1]. (d) In classical conditioning the animal links two stimuli [1]; in operant conditioning the animal learns that its own behaviour leads to a reward or punishment [1]. [7] Examiner insight: A comparison states both sides, not just one type of learning.

10. (a) The dog is given the target scent to sniff [1]. It is rewarded with food or a toy each time it finds or indicates the scent [1]. The dog repeats the behaviour that brings a reward (operant conditioning) [1]. (b) The horse is repeatedly exposed to crowds, flags and noise in a safe setting [1]. It learns that the stimuli are harmless and stops reacting (habituation) [1]. Calm behaviour can be rewarded [1]. (c) Before: 14 / 20 x 100 = 70 %; after: 18 / 20 x 100 = 90 % [1]. Increase = 20 percentage points [1]. [8] Examiner insight: Describe the stimulus and the reward; “the animal is taught” is too vague.

11. (a) Sound: for example bird song or an alarm call [1]. Chemical: for example an ant trail or scent marking [1]. Visual: for example a peacock tail display or a posture [1]. (b) An alarm call travels quickly to many animals and can be started and stopped at once [1]. A chemical signal is slow to spread and lasts after the danger has passed, so it cannot show where the predator is now [1]. [5] Examiner insight: A “suggest” answer must link to the situation given, here a predator attacking now.

12. (a) The display advertises the male’s quality, such as health or fitness [1]. The female can use it to choose a suitable mate [1]. (b) A mate for a breeding season [1]. (c) Any two from: a parent may be caught by a predator when it leaves the nest to feed; energy is used feeding the chicks; the parent may be weakened for later breeding [1] [1]. (d) Imprinting [1]. The chicks stay close to the parent, so they are fed and protected [1]. (e) Habituation [1]. The birds stop wasting energy and time hiding from a harmless stimulus [1]. [9] Examiner insight: Answer each lettered part separately: name the behaviour first, then explain.

Where marks are usually lost

• Writing “message” or “nerve” instead of “impulse” and “neurone”.
• Leaving the synapse chemical out of a reflex arc description.
• Saying a gland contracts, or a muscle secretes.
• Giving only a benefit of parental care when a risk is asked for.
• Confusing habituation with classical conditioning, or classical with operant.
• Describing imprinting without the early, short period.
• Skipping working lines, units or the decimal places asked for.

Next steps

• Revise with the revision notes or study guide.
• Use the OxfordAQA IGCSE Biology hub and checklist.
• Take one of the free 10-minute diagnostics to find your next weak spot.
• Book a free trial class.

Official syllabus

OxfordAQA International GCSE Biology (9201), Version 5.2, for exams May/June 2018 onwards, published by OxfordAQA: sections 3.4.1 and 3.4.6.