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
A food web demonstrates the importance of biodiversity within an ecosystem
