Three species, three outcomes: Some species go extinct when protection comes too late. Some are critically endangered but survive with help. Some recover when strong action comes in time. Learn one real species of each kind.
Why species decline: what to look for
- Habitat loss or degradation: forest cleared, rivers polluted or dammed.
- Overhunting, poaching or illegal trade, often because it was seen as a pest or a resource.
- A narrow range (endemic to one island or region), so every individual faces the same threats.
- Invasive species and disease brought by people.
- Slow reproduction, a specialised niche or a small gene pool, so it cannot recover from losses.
- Being a top predator: few in number to begin with, and often killed by people.
Remember it as: Habitat, hunting, range, invaders, slow breeding, top of the chain.
Extinct (SL example): the thylacine. It survived only on Tasmania (narrow range). Farmers blamed it for killing sheep (seen as a pest), and the government paid bounties for more than 2000 killed. Farms replaced its forest (habitat loss), and dogs may have spread disease. It was protected in July 1936; the last one died that September. Impact: Tasmania lost its top predator, and people lost a unique animal now known only from film.
Early action works best: Protection that comes after a species is down to a handful, as with the thylacine's in 1936, is usually too late. Say so when you judge a strategy.
Free preview
This is the free notes preview
You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it with your first topic free to keep:
- FlashcardsLock in vocabulary and key terms with spaced repetition.
- Practice questionsAnswer exam-style questions and get instant AI marking.
- Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
- Personalised study planA daily plan built around your exam date and weak areas.
For a critically endangered species, ask what its loss would mean, for nature and for people.
The impacts of a species' decline or loss
- On ecosystems: biodiversity falls; the species it ate increase; species that ate it decline.
- If it is a keystone species, the effects cascade through the whole food web.
- Lost ecosystem services, such as pollination, seed spreading or cleaning up carcasses.
- On societies: lost tourism income, aesthetic beauty, and cultural or spiritual value.
- An ethical loss: a species with its own right to exist (biorights) is gone for ever.
Critically endangered (SL example): the kākāpō. Hunting, forest clearing and predators brought by people (cats, rats, stoats) cut it to 51 birds by 1995. It breeds only every two to four years (slow reproduction). Impacts: it spread seeds and grazed plants in the forest, and it is a taonga (treasure) of great cultural and spiritual value to the Māori.
Ecosystems AND societies: The guide asks for both. Give at least one impact on the ecosystem (food web, biodiversity, services) and one on people (tourism, culture, ethics).
Learn what examiners really want
See exactly what to write to score full marks. Our AI shows you model answers and the key phrases examiners look for.
Some species have been moved to a lower-risk rank because people stepped in.
Strategies that have improved a status
- Legal protection: hunting bans, national laws and international agreements such as a whaling ban or CITES.
- Protected areas and habitat restoration.
- Captive breeding and release, or raising young safely before release (head-starting).
- Removing predators or invasive species, often on islands.
- Partnerships of governments, NGOs, local and indigenous people, and volunteers.
- The earlier the action starts, the more likely it is to work.
Improved by intervention (SL example): the humpback whale. Whaling for oil and meat cut its numbers by around 90% (overhunting). Protection in 1966 and a worldwide ban on commercial whaling from 1986 (legal protection, international agreement) let it recover: endangered in 1986, least concern since 2008. Impacts of the recovery: whale watching now brings tourism income to many coasts.
Improved is not safe: A better status does not mean the threats have gone: humpbacks still drown in fishing gear, lynx are still killed on roads. Mention this when you judge the strategy.
Exam questions give a fact file on a programme and ask you to evaluate it.
How to judge a strategy
- For: numbers rose; the status improved; other native species benefit; many partners share the work.
- Against: the cause of decline (habitat loss) is not fixed; low genetic diversity; very costly.
- Against: it depends on people: stop the help and numbers may fall; predators or poachers may return.
- Conclusion: weigh both sides and judge, e.g. 'saved from extinction, but not yet self-sustaining'.
- At most two points on each side count in a [3]; the judgement can be the third mark.
- For: separate populations spread the risk of one disease or disaster.
- Against: killing predators or taking eggs may be unethical; captive-raised animals may struggle when released.
Strengths
- Numbers rose from 51 (1995) to 252 (2022).
- Removing predators from islands helps other native birds.
- Many partners: the government, Māori iwi and volunteers.
Limitations
- Very few predator-free islands left, so little room to grow.
- Low genetic diversity: many eggs do not hatch.
- Depends on feeding, monitoring and costly care.
A balanced conclusion: Although the kākāpō has increased five-fold since 1995, it still depends on intensive human care, so the programme has saved the species but not yet made it self-sustaining.
The same steps for a law: the ban on whaling worked, because humpback numbers recovered; but it does not stop whales drowning in fishing gear, so on its own it is not enough.
Legal protection: a trap: When judging a law, 'it worked because there are now enough to cull' is not accepted. Say which points show the law worked (numbers recovered) and which show it did not (legal shooting, poaching, culls).
Never wonder what to study next
Get a personalized daily plan based on your exam date, progress, and weak areas. We'll tell you exactly what to review each day.
How this comes up: Paper 2, Section B (b): explain the causes and consequences of the loss of a named species [7]; Paper 1: evaluate a conservation strategy from a fact file [3].
Many species have been lost because of human activity.
Explain the causes, and the possible consequences, of the extinction of a named species due to human activity.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.