Biodiversity (AQA GCSE Combined Science: Synergy: Life & Environmental Sciences): Revision Note

Importance of Biodiversity

• Biodiversity is the variety of different species of organisms on Earth, or within an ecosystem

• Biodiversity is greater in ecosystems that contain a wide range of different habitats

  • Each habitat provides different conditions and resources, allowing a larger variety of species to survive and maintain larger populations

  • Small populations are at greater risk of dying out if an ecosystem is disrupted, as there are fewer individuals to reproduce and less genetic variation

  • Ecosystems with high biodiversity provide the resources needed to sustain life, including food, oxygen, clean water and raw materials, which are essential for human survival

  • High biodiversity also provides economic benefits, as it supports resources used in agriculture, fishing and forestry

• A high biodiversity ensures the stability of ecosystems by reducing the dependence of one species on another

• For example, for the food web below:

  • If the mouse population was suddenly wiped out, the fox and the hawk populations might decrease but would not be wiped out too, as mice are not their only food source

  • This example ecosystem has sufficient biodiversity to support the fox and hawk populations

  • The fox population can still depend on the rabbit and frog populations for food

  • The hawk population can still depend on the frog and sparrow populations for food

A food web demonstrates the importance of biodiversity within an ecosystem