Eduqas A-Level Geography A110QS
Coastal LandscapesLandscape
Glaciated LandscapesLandscape
Changing Places
Water and Carbon Cycles
Global Migration
Global Governance of the Oceans
Tectonic Hazards
EcosystemsContemporary theme
Economic Growth and Challenge: IndiaContemporary theme
Economic Growth and Challenge: ChinaContemporary theme
Development in an African ContextContemporary theme
Energy Challenges and DilemmasContemporary theme
Weather and ClimateContemporary theme
Geographical Skills
Ecosystems
Threats to biodiversity from local to global scale
- 3 things to know
- Component 3 Section B
Overview
Five direct threats to biodiversity, habitat fragmentation and edge effect.
What you need to know
Answer each one before you reveal it.
Name five direct threats to biodiversity.
Why is habitat loss the greatest single threat?
Questions from this subtopic
Each one with the model answer underneath.
- 1
Distinguish direct and indirect threats to biodiversity.
Model answer
A direct threat physically removes or damages organisms and habitat, such as logging or hunting. An indirect threat alters the conditions on which species depend, such as climate change.
- 2
Name five direct threats to biodiversity.
Model answer
Habitat clearance, overexploitation, pollution, invasive species and direct persecution are five direct threats. Habitat loss is the largest of them.
- 3
Why is habitat loss the greatest single threat?
Model answer
Clearance for farming, settlement and infrastructure removes the space species need to live. Around three-quarters of the ice-free land surface has been significantly altered by people.
- 4
What is habitat fragmentation, and why does it matter?
Model answer
Fragmentation breaks a continuous habitat into small, isolated patches. Small populations lose genetic diversity, and species cannot migrate between the fragments.
- 5
What is the edge effect?
Model answer
The edge effect is the change in conditions at the boundary of a habitat fragment. Higher light, wind and temperature at the edge favour different species from the interior.
- 6
Give an example of overexploitation.
Model answer
Atlantic cod stocks off Newfoundland collapsed in 1992 after decades of industrial trawling. A moratorium was imposed and the stock has still not fully recovered.
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