Endangered Species and Conservation
AdvancedHabitat destruction, overhunting, pollution and invasive species push species to the brink. Conservation needs reserves, laws and restoration; personally, refuse wildlife products and cut plastic.
- Main causes of endangerment: habitat destruction, overhunting, pollution, invasive species.
- Extinction is forever — once a species is gone it never returns.
- Conservation tools: reserves, laws (such as CITES), captive breeding and habitat restoration.
文體小知識：科普知識文章用生活實例解釋科學概念，先看現象再講原理，讀完就能解釋日常見到的東西。
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1The dinosaurs died out over sixty million years ago, yet species today are vanishing far faster than the natural background rate — scientists call it the sixth mass extinction. The cause is not an asteroid but human activity.
2Four main forces drive species towards extinction: habitat destruction (reclamation, clearing, pollution), overhunting and illegal trade (pangolins, rhinos), pollution (plastics, oil), and invasive species crowding out natives. Hong Kong's Chinese white dolphin and black-faced spoonbill face exactly these threats.
3Conservation answers in layers: reserves to hold the habitat, laws to control hunting and trade, captive breeding and release, and restoration of damaged wetlands and woods. Mai Po Nature Reserve is a success story — protecting the wetland protects tens of thousands of migratory birds with it.
4Conservation is not only for governments and scientists: refuse wildlife products, choose sustainable seafood, cut single-use plastic, take your rubbish home — every small choice shapes other species' futures. This is the final lesson of S2 Integrated Science; put it to good use.
1Summary 重點摘要
Habitat destruction, overhunting, pollution and invasive species push species to the brink. Conservation needs reserves, laws and restoration; personally, refuse wildlife products and cut plastic.
2Vocabulary cards Vocabulary
A species so reduced in numbers that it faces the risk of extinction.
The permanent disappearance of a species when every individual has died.
The loss of homes through clearing, reclamation and pollution — the leading cause of endangerment.
Killing faster than the species can breed, collapsing its population.
A species introduced to a new area that spreads fast and crowds out native life.
The measures and actions protecting species and their habitats, such as reserves and legal controls.
A protected, managed area set aside for habitats, e.g. the Mai Po Nature Reserve.
The international agreement controlling trade in endangered wild species and their products.
Seafood caught or farmed in ways that do not harm fish stocks or ocean ecosystems.
3Step by step Steps
- Cause 1: habitat destructionHabitat destruction is the top cause of endangerment: mangroves are reclaimed and woodland cleared, so creatures lose their shelter and feeding grounds and numbers crash; even without hunting, a species that loses its home gradually fades. Reclamation and land development in Hong Kong keep shrinking habitats. Once a habitat is destroyed, recovery takes years — and sometimes the species never returns.
- Cause 2: overhunting and illegal tradeOverhunting and illegal trade collapse populations: pangolins are slaughtered because their scales are wrongly believed to be medicine, and rhinos are poached for their horns. When killing outpaces breeding, a population cannot recover; slow-breeding large animals suffer most, and once numbers fall, a comeback is very hard. International conventions have banned this trade, yet black-market demand still drives the poaching.
- Cause 3: pollution and invasivesPollution and invasive species are invisible killers: plastic waste drifts into the sea and turtles swallow it, mistaking it for jellyfish, and die; pesticides and sewage empty the streams. Invasive mile-a-minute weed climbs over woodland, shading native plants to death. Introduced species meet no natural enemies in their new home, breeding beyond control, crowding out natives and throwing the local ecology off balance for years.
- Hong Kong casesHong Kong has its own endangered cases: the Chinese white dolphin is threatened by marine works, boat traffic and polluted water, with numbers falling in recent years; only a few thousand black-faced spoonbills remain worldwide, and losing their wintering wetland at Deep Bay would be unthinkable. To guard these species is to guard the whole marine and wetland ecosystem they depend on — the greatest value of flagship species in conservation.
- Conservation measuresConservation works on many fronts: Mai Po Nature Reserve and marine parks put key habitats under protection; laws control hunting and wildlife trade, with the CITES convention regulating endangered-species commerce internationally; captive breeding and release help populations recover; and restoring degraded habitats lets wildlife come home. Government legislation, scientific research and the action of conservation groups — all are indispensable.
- What individuals can doConservation begins in personal habits: refuse wildlife products so poaching loses its market; choose sustainable seafood to avoid overfishing; cut single-use plastic to protect marine life; take your rubbish home after hikes; and keep your distance from wild animals, neither feeding nor disturbing them. Day after day, small choices added together become the great decisive factor in whether species survive.
4Diagrams Diagrams
5Worked example Example
Example: reclamation is planned beside a wetland, and migratory bird numbers have been falling for years. Analyse the cause and suggest two conservation actions.
- Reclamation shrinks the mudflat, cutting the birds' feeding grounds — habitat destruction.
- The works add noise, sediment and water pollution, driving more wildlife away.
- Action 1: designate the wetland a nature reserve and strictly limit the works.
- Action 2: restore the degraded mudflats and mangroves, and monitor bird numbers long term.
- Answer: The falling numbers are mainly caused by habitat destruction: reclamation shrinks the mudflat and its feeding grounds, while noise and pollution from the works drive wildlife away. Suggestions: first, designate the wetland a nature reserve and strictly limit the works; second, restore the degraded mudflats and mangroves and monitor bird numbers long term to make sure the measures work.
6Common mistakes Mistakes
7Quick check Quick check
Q1Give two causes that drive species towards extinction.
Q2What is CITES?
Q3Which endemic amphibian of Hong Kong needs protection?
Q4Give two conservation actions an individual can take.
Q5Why is protecting habitats more fundamental than captive breeding alone?
8Recap Recap
- Main causes of endangerment: habitat destruction, overhunting, pollution, invasive species.
- Extinction is forever — once a species is gone it never returns.
- Conservation tools: reserves, laws (such as CITES), captive breeding and habitat restoration.
- Hong Kong's flagships: Chinese white dolphin, black-faced spoonbill, Romer's tree frog.
- Personal conservation: refuse wildlife products, cut plastic, choose sustainable seafood, never disturb wildlife.