Human Impact on Biodiversity

Human activities are the primary driver of biodiversity loss in the modern era. Scientists have described the current rate of extinction as a "sixth mass extinction" — the first caused by a single species. Understanding how human activities threaten biodiversity, and what can be done to mitigate these threats, is essential for Edexcel A-Level Biology.

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The Scale of Biodiversity Loss

Current extinction rates are estimated to be 100 to 1,000 times higher than the natural background extinction rate. Key statistics:

• Approximately 1 million species are currently threatened with extinction (IPBES, 2019)
• Vertebrate populations have declined by an average of 69% since 1970 (WWF Living Planet Report, 2022)
• 75% of the Earth's land surface has been significantly altered by human activities
• 85% of wetland area has been lost since 1700
• Global forest cover has declined by approximately 32% since pre-industrial times

Exam Tip: When discussing human impacts on biodiversity, use specific data and statistics where possible. Examiners reward answers that demonstrate awareness of the scale and severity of the problem.

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Major Threats to Biodiversity

1. Habitat Destruction and Fragmentation