Question 3: Explain Merit

Practises Social behaviour & spatial behaviour

Grey wolves (Canis lupus) live in packs of about 2 to 20 closely related animals that form a hierarchy, in which agonistic behaviour (dominance displays, submissive displays and threats) matters. The paper’s figure ranks the pack. The alpha male and female lead decisions, including cooperative hunts and defence of the territory; they are monogamous and the only pair to breed. Betas, of either sex, are second in command and help keep order on hunts and in other pack activities. Deltas follow the alphas and betas, help hunt, look after pups and help defend the territory. Omegas rank lowest: they receive the most aggression, eat last and eat least.

Explain how the hierarchy is maintained, why pack members show kin selection, and an advantage and a disadvantage, for a wolf below the alpha pair, of living in the hierarchy rather than alone.

The 2025 paper, page 10 ↗ Marking schedule, page 6 ↗

Work it out

Try it on paper first. Stuck? Take one hint at a time.

1 Name at least two ways the hierarchy is kept, and say why they work.
Dominance displays: higher-ranked wolves stand tall, hold the tail and ears up and stare. Submission: a lower-ranked wolf crouches, tucks its tail, avoids eye contact, rolls over or licks a dominant wolf’s muzzle. Ritualised threats, growling and snarling, put a wolf back in its place. Each settles rank without a real fight, so no one is badly hurt.
2 Why would a wolf that never breeds help raise pups?
The pack is closely related: the pups are usually the helper’s brothers and sisters, sharing about half its alleles. Each pup it helps survive carries copies of the helper’s own alleles, so helping passes them on indirectly. That is why the pack shows kin selection.
3 Give one example and link it to relatedness.
A delta wolf caring for the alphas’ pups spends time and energy, and gets no pups of its own, but the pups share its family alleles, so their survival carries those alleles on.
4 How does pack life raise a lower-ranked wolf’s chance of surviving?
Hunting together, the pack kills large prey that one wolf could not, and the defended territory secures food, water and shelter. Higher ranks lead in defence, so lower ranks face less risk. A wolf in the pack is more likely to survive than one alone.
5 What does it cost, and why might it still pay?
It eats after the others and gets less, so it may be underfed, and the lowest ranks take the most aggression, which brings stress and injury. Those costs are paid for the benefits of protection and a share of food that it could not get alone.

Answer The hierarchy is kept by agonistic behaviour: dominant wolves stand tall with tail and ears raised and stare, while subordinates crouch, tuck their tails, avoid eye contact, roll over or lick a dominant wolf’s muzzle, and ritualised growls and snarls keep lower wolves in line. These settle rank without serious fights. Pack members show kin selection because they are closely related: the pups are usually their siblings and share about half their alleles, so a non-breeding wolf that hunts for them, guards them or cares for them, as delta wolves do, passes on copies of its own alleles indirectly. Living in the pack raises a lower wolf’s chance of survival, because the pack can kill large prey and defend a territory with food, water and shelter, with the higher ranks taking the lead in defence. The cost is less food, which may leave it underfed, and more aggression from above; it pays these costs for protection and a share of food it could not get alone.

What the marker wanted

Achieved The describe points: hierarchy, territory, kin selection with relatedness, an example, and an advantage and a disadvantage of pack life.
Merit Explains: at least TWO ways the hierarchy is kept; why pack members show kin selection; a case of it, linked to how related the wolves are; an advantage of pack life, linked to a better chance of survival; and a disadvantage, weighed as a cost against a benefit. Three make M6.

One answer, N0 to E8. Merit points sit above the Achieved ones: two give M5, three M6.

In our words, from NZQA’s 2025 marking schedule.

Common mistake

Explaining how the hierarchy is kept and what pack life costs and gives, but not why helping relatives is kin selection. NZQA’s 2025 report says this was common in Merit answers.

How did it go?

Got it moves it further out. Review brings it back tomorrow.