Biodiversity (Edexcel GCSE Biology: Combined Science)

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Biodiversity

  • Biodiversity is the range and variety of different species of organisms within a given area (e.g. on Earth or within an ecosystem)
  • It considers not only the species richness, but also the variation within each species including the relative abundance (i.e. the population size) of each species present
    • For example, a high biodiversity would be found in an environment with lots of different species which show a lot of variation and are all evenly distributed across the study area

The importance of biodiversity

  • Different species depend on each other for many things, including:
    • Food
    • Shelter (e.g. birds nesting in trees)
    • Maintenance of the physical environment (e.g. tree roots provide stability for soils, ensuring they do not get washed away. This, in turn, provides a stable habitat for other plant species)

  • High biodiversity ensures the stability of ecosystems by reducing the dependence of one species on another for these three things
  • Populations with high levels of diversity are also more likely to be resilient to sudden environmental impacts or diseases
  • Consider 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 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

Food web, IGCSE & GCSE Biology revision notes

A food web demonstrates the importance of biodiversity within an ecosystem

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Lára

Author: Lára

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.