Biodiversity and Human Impact

Biodiversity is the variety of all the different species of organisms on Earth, or within a particular ecosystem. High biodiversity is essential for the stability of ecosystems and for human well-being. However, human activities are reducing biodiversity at an alarming rate. This lesson covers what biodiversity is, why it matters, and the ways in which humans are threatening it, as required by AQA GCSE Biology.

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What Is Biodiversity?

Biodiversity refers to the variety of living organisms in an area. It can be measured at different scales:

Scale	What It Measures	Example
Species diversity	The number of different species and the abundance of each species in an area	A meadow with 40 species of wildflower is more biodiverse than one with 5
Genetic diversity	The variation in alleles (versions of genes) within a species	Cheetahs have low genetic diversity; dogs have high genetic diversity
Ecosystem diversity	The range of different ecosystems in an area	A region with forests, wetlands, grasslands and rivers has high ecosystem diversity