Human Impact on Biodiversity Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Investigate how human activities are reducing biodiversity and why maintaining biodiversity is crucial for the future of our species.

• Explain how human activities reduce biodiversity and threaten ecosystems
• Evaluate the impact of deforestation, pollution, and climate change on species survival
• Analyse conservation strategies and their effectiveness in protecting biodiversity
• Apply knowledge of ecosystem interactions to predict consequences of habitat destruction

Key ideas to keep in view

Use this lesson to stay inside B6.1 Monitoring and maintaining the environment while connecting the detail back to the wider B6: Global challenges topic.

• B6: Global challenges
• B6.1 Monitoring and maintaining the environment
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from Human Impact on Biodiversity before testing yourself from memory.

• Imagine waking up tomorrow to find no bees, no forests, and no fish in the oceans. This isn't science fiction — it's the direction we're heading if biodiversity continues to collapse at current rates.
• Biodiversity isn't just about saving cute animals. It's about human survival. We depend on other species for food, medicine, clean air, and stable climate. When species disappear, entire ecosystems can collapse, taking their life-supporting services with them.
• The variety of all the different species of organisms on Earth, or within an ecosystem.
• Think of biodiversity like a giant web. Remove too many threads and the whole structure falls apart. Each species plays a role — predators control prey populations, decomposers recycle nutrients, and plants produce oxygen. Lose key species and the system breaks down.
• Humans are causing the sixth mass extinction in Earth's history. But unlike asteroid impacts or volcanic eruptions, this one is entirely our doing. Let's examine the main culprits.
• The process by which natural habitats are damaged or destroyed, making them unable to support the species that live there.
• Deforestation is the biggest threat. We're clearing forests for agriculture, urban development, and logging. Tropical rainforests are particularly vulnerable — they contain 50% of Earth's species but cover only 6% of land surface.
• Pollution poisons ecosystems. Pesticides kill beneficial insects alongside pests. Plastic waste chokes marine animals. Chemical runoff creates dead zones in rivers and oceans where nothing can survive.
• Climate change is shifting habitats faster than species can adapt. Coral reefs bleach in warming oceans. Arctic species lose their ice habitat. Weather patterns change, disrupting migration and breeding cycles.
• Overfishing and hunting remove species faster than they can reproduce. Large predators like sharks and tigers are particularly vulnerable because they reproduce slowly and need large territories.

Continue through the topic

Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.